TICKET #8

1. The presence of a toxin in the pathological material is determined by:

1. By chemical method

2. Biological assay in mice

3. The presence of bombing

4. Presence of clostridial botulism

5. Infection of two-month-old kittens

2. Non-specific microflora of food products:

1. Enterococci

2. Lactic acid bacteria

3 Creamy Streptococcus

4. Salmonella

5. All of the above

3. Methods of sanitary and bacteriological research include all of the following, except:

1. Tampon method

2. Method of agar fillings

3. Method Grace

4. Sterile gauze pads

5. Adelson method

4. The unfavorable sanitary condition of medical institutions is associated with:

1. The presence of E. coli

2. An increase in the number of multidrug-resistant pathogenic staphylococci

4. High humidity

5. None of the above factors

5. Enteroviruses cause:

1. Dysentery

2. Hepatitis B, D

3. Polio

4. Parainfluenza

5. Gastritis

TICKET #9

1. When diagnosing which food toxic infections, a biological test is performed:

1. Staphylococcal

2. Botulinum

3. Clostridial-induced perfringens

4. Caused by Proteus

5. For intestinal infections

2. 12 GPTU students were admitted to the hospital with a diagnosis of food

toxic infection". What material is not taken for research:

1. Vomit

3. Bowel movements

5. Leftover food

3. When looking for ways to transmit infection, the following are critical:

1. Identification of conditionally pathogenic flora

2. Detection of pathogenic microorganisms, pathogens of infectious diseases

3. Detection of single pathogenic staphylococci

4. Identification of E. coli

5. Unfavorable sanitary condition

4. The titration method is used:

1. To determine the TMF

2. To determine MAFAM

3. To determine the PSD

4. For direct counting in the Goryaev chamber

5. Not used in sanitary microbiology

5. Total Microbial Count (TMC) is:

1. Method of direct detection of the pathogen

2. Method for determining sanitary-indicative microorganisms

3. An indicator of the intensity of environmental pollution by organic substances

4. The value of the reciprocal titer

5. Indicator of fresh fecal contamination

Topic: SANITARY MICROBIOLOGY. MICROFLORA OF FOOD PRODUCTS AND HOUSEHOLD ITEMS.

TICKET #10

1. A meat sample was delivered to the laboratory 6 hours after selection. Actions of the bacteriologist:

1. Immediately start research

2. Place in the refrigerator

3. Take the middle portion for research

4. Refuse to study

5. Heat treat

2. Diseases that can be transmitted through milk:

1. Tuberculosis

2. Q fever

3. Diphtheria

4. Typhus

5. Tularemia

3. In the laboratory diagnosis of food bacterial poisoning, the following media can be used for inoculation, except:

1. Selenite broth

2. Endo environments

3. Bismuth sulfite agar

4. Ru environments

5. Yolk-salt agar

4. For the study of washouts, you can use:

1. Determination of the total number of microbes

2. Definition of BGKP

3. Identification of pathogenic flora of the intestinal group

4. Identification of pathogenic staphylococcus aureus

5. All of the above

5. Coliform bacteria are considered:

1. Microorganisms that break down lactose and glucose to acid and gas at a temperature of 37 ° C

2. Microorganisms that break down only lactose to acid and gas at 37 ° C

3. Microorganisms that break down only lactose to acid and gas at a temperature of 43-44.5 ° C

4. Microorganisms that are an indicator of self-purification

5. Microorganisms as an indicator of contamination

ANSWERS

Subject: SANITARY MICROBIOLOGY. MICROFLORA OF FOOD PRODUCTS AND HOUSEHOLD ITEMS.

	4,5
	1,2
		1,2

Theme: MUSHROOMS

TICKET #1

1. Mushrooms belong to the kingdom:

2. Fungi (Mucota)

4. Basidiomycetes

2. Methods for laboratory diagnosis of coccidiosis do not include:

1. Microscopic

2. Bioassay

3. Serological

4. Allergic

5. Histological

3. Chromomycosis:

1. Localized tumor formations

2. Subcutaneous mycosis

3. Ringworm

4. Deep (systemic mycosis)

4. Antifungal drugs are:

1. Nystatin

2. Levorin

3. Orungal

4. None of the above

5. All of the above

5. Biological properties of actinomycetes:

1. Facultative anaerobes

2. Do not grow on nutrient media

3. Chemoorganotrophs

4. Sugar is broken down into acid and gas

5. Microaerophiles

Theme: MUSHROOMS

TICKET #2

1. GIF cell does not contain:

1. Contoured core

2. Mitochondria

3. Golgi apparatus

4. Segresomes

5. Volutin grains

2. The causative agents of dermatomycosis are not:

3. Epidermophyton

3. For laboratory diagnosis of epidermomycosis use:

1. Infection of animals

2. Agglutination reaction

3. Infection of chicken embryos

4. Microscopy of hair, nails, skin scales

5. Allergic method

4. The pathogenesis of candidiasis does not include:

2. It develops against the background of hypovitaminosis, long-term use of antibiotics

3. AIDS is a manifest infection

4. Contribute to exogenous factors

5. A pustule, an ulcer is formed at the injection site

5. Reproduction of mushrooms occurs:

1. Sexually

2. Non-sexually

3. Reproduction

4. Transduction

5. Through photosynthesis

Theme: MUSHROOMS

TICKET #3

1. Spore, germinating forms:

1. growth tube

2. Sperm shape

3. Wings of a seagull

4. "Scrambled eggs"

2. Epidermomycosis is characterized by:

1. Damage to the skin and nails

2. Hair damage

4. Infection occurs through water

5. Form granulomatous foci in the lungs

3. Subcutaneous mycoses include:

1. Sporotrichosis

2. Microsporia

3. Chromomycosis

4. Histoplasmosis

5. Blastomycosis

4. Prevention of candidiasis:

1. Live vaccine

2. Immune serum

3. Killed vaccine

4. Identification and destruction of sick animals

5. Bacteriophage

5. What does not apply to the stages of development of actinomycosis:

1. Formation of small subcutaneous nodules

2. Merging of nodules into a dense infiltrate

3. Formation of hemorrhages

4. Fistula formation

5. Discharge of yellow pus with dense whitish granules

Theme: MUSHROOMS

TICKET #4

1. Risk factors for deep mycoses are not:

1. Hormonal and hematological diseases

2. Corticosteroid, immunosuppressive therapy

3. Major surgical interventions

4. Age of patients (newborns, elderly)

5. Staphylococcal diseases

2. Ringworms include:

1. Trichophytosis

2. Microsporia

4. Epidermophytosis

5. All of the above

3. Methods for laboratory diagnosis of subcutaneous mycoses:

1. Mycological

2. Microscopic

3. Biological

4. Histological

5. Cytochemical

4. For the identification of Candida fungi do not use the study:

1. Filamentation

2. Chlamydospore

3. Basidiospore

4. Growth tubes

5. Quantitative seeding

5. Immunity with actinomycosis:

1. Non-sterile

2. Immunity is fragile

3. Antitoxic

4. Phagocytic

5. Non-specific

Theme: MUSHROOMS

TICKET #5

1. Perfect Mushrooms:

1. Deuteromycetes

2. Reproduce sexually and asexually

3. Have endogenous spores

4. Ascomycetes

2. Trichophytia, microsporia and favus are characterized by:

1. Damage to the skin and nails

2. Hair damage

3. Damage to internal organs

4. Inhibition of hematopoiesis

5. CNS damage

3. Candida pathogenicity factors include all of the following, except:

1. Hemolysins

2. Endoplasmic coagulase

3. Endotoxin

4. Neuraminidase

5. Hyaluronidase

4. Fungi are different from bacteria:

1. The presence of DNA

2. Presence of RNA

3. They do not have a cellular structure

5. The presence of a differentiated nucleus

5. Aspergillus:

1. Anaerobes

2. Strict aerobes

3. Stable in the external environment

4. Not pathogenic for humans

5. Do not grow on nutrient media

Theme: MUSHROOMS

TICKET #6

1. Indicate what is wrong in the described process of reproduction of mushrooms:

2. Getting into the substrate

3. Capsule formation

4. Growth into hyphae

5. Mycelium formation

2. Microsporia is infected:

1. From cats

2. From dogs

3. Through the water

4. From sick people

5. Airborne

3. Candida is characterized by:

1. Quantitative accounting of grown colonies

2. Reproduce by budding, division

3. Do not grow on artificial nutrient media

4. Gram-negative

5. Optimum temperature growth 42°С

4. Fungal dimorphism is:

1. The ability to stain under the action of dyes

2. Resistant to dyes

3. Ability to grow in yeast and mycelial forms

4. Tinctorial property

5. Arrangement of cells in pairs

5. Aspergillus Mushrooms:

1. Prokaryotes

2. "Lech mold"

3. On the bottle-shaped thickening, a chain of spores resembling water splashes

4. Contains the Protein Flagelin

5. Cultured in chicken embryos

Theme: MUSHROOMS

TICKET #7

1. The body of the fungus:

1. Mycelium

3. Zygospores

5. Conidia

2. For trichophytosis is not typical:

1. Among the cells of the epidermis - septate filaments of mycelium

2. In the nails - branching mycelium

3. Spores inside the hair

4. Hair - "a bag of nuts"

5. Cheilitis of the corners of the mouth

3. Does not apply to forms of candidiasis:

1. Thrush

2. Acute atrophic stomatitis

3. Gingival stomatitis

4. Leukoplakia

5. Mycetoma

4. Penicillium Mushrooms:

1. Have racemose branches at the ends

2. "Lech mold"

3. Mushroom-"brush"

4. On the bottle-shaped thickening, a chain of spores resembling water splashes

5. Are arranged in the form of packages or bales, consisting of 8 cells

5. Prevention of actinomycosis is carried out using:

1. Bacteriophage

2. Antitoxic serum

3. Toxoid

4. Gamma globulin

5. Not designed

Theme: MUSHROOMS

TICKET #8

1. The causative agents of deep mycoses are all of the following

microorganisms, except:

1. Cryptococas neoformans

2. Histoplasma capsulatum

3. Coccidioides immitis

4. Sporotrichum schenerii

5. Blastomyces dermatidis

2. For the cultivation of dermatomycetes use:

1. Alkaline agar

2. Wednesday Endo

3. Wort agar

4. Agar Difko

5. Wednesday Rapopport

2. Not typical for Candida:

1. Gram positive

2. Form oval budding cells

3. Grow on Sabouraud's medium

4. Reproduce by budding, division

5. Cause deep mycoses

4. What forms of the disease corresponds to the microscopic picture:

1. Candidiasis A. Polymorphic fungal infections are found in the hair.

2. Epidermophytosis elements

3. Favus B. Spores of the fungus are located inside the affected

4. Trichophytosis of the hair, completely filling it

B. Unicellular microorganisms round or

oval shape

G. Mushrooms surround the hair in several layers

D. Elements of the fungus are contained in the scales of the skin

5. Actinomycetes are characterized by:

1. Formation of specific granulomas

2. Lymphogenic pathway

3. CNS damage

4. Fecal-oral route of infection

5. Biological mode of infection

Theme: MUSHROOMS

TICKET #9

1. Deep mycoses are characterized by:

1. Formation of suppurative granulomatous lesions

2. Lighter flow

3. Hematogenous mode of spread

4. Transmitted from person to person

5. Localized in nails, hair

2. Among the students living in the same dormitory room, there were several cases of epidermophytosis of the feet. What investigations should be done to make a diagnosis:

1. Microscopy of skin scales

2. Isolation of pure culture

3. Precipitation reaction

4. Skin-allergic test

5. Infection of cell culture

3. Name the methods of laboratory diagnostics for candidiasis:

1. Microscopic

2. Cultural

3. Biochemical

4. Serological

5. All named methods

4. Actinomycetes belong to:

1. Eukaryotes

2. Prokaryotes

3. Lower mushrooms

4. Zygomycetes

5. Deuteromycetes

5. The causative agents of opportunistic mycoses can be:

Theme: MUSHROOMS

TICKET #10

1. True mycelium:

1. Separate cells that do not have a common shell

2. System of curved tubes with baffles

3. Bears spores

4. Serves to fix and nourish the fungus

5. Fabric form

2. Deep mycoses include:

1. Candidiasis

2. Milleseidosis

3. Cryptococcosis

4. Histoplasmosis

5. Aspergillosis

3. In a person who has been treated for a long time with tetracycline, on the mucous membrane

oral cavity appeared white raids. How to make a diagnosis:

1. Serological

2. Microscopic

3. Isolation of pure culture

4. All named methods

5. None of the listed methods

4. Actinomycetes:

1. Sensitive to antibacterial drugs

2. Thin branching mycelium is formed in tissues

3. Have a differentiated core

5. Molds

5. Mycelium is distinguished:

1. Air

2. Vegetative

3. Substrate

4. Reproductive

5. All options are correct

ANSWERS

On the subject: MUSH AND B S

					1,3
					1,2
		1,2
		1,2	1,2		2,3
		1,2	1,2		2,3
				2,3
	1,3	1,2		1B,2D,3A,4B,G	3,4
		3,4		1,2

Topic: ANAEROBS.

TICKET #1

1. For cultivation of causative agents of gaseous anaerobic infection

use:

1. Levenshtein-Jensen environment

2. Wilson-Blair medium

3. Physical methods

4. Leffler medium

5. Wednesday Ulengut

2. Tetanus bacillus is characterized by the formation of:

1. Tetanospasmin

2. Endotoxin

3. Hyaluronidase

4. Plasmacoagulase

5. Fibrinolysin

3. For microbiological diagnosis of tetanus, use:

1. Bioassay on white mice

2. Allergy test

4. Neutralization reaction on animals

5. Seeding on Kessler's medium

4. The test material for botulism is not:

3. Vomit

4. Gastric lavage

5. Bowel movements

5. Find a match:

1. Cl.perfringens A. Does not ferment carbohydrates

2. Cl.tetani B. Causes the development of gelatinous edema,

4. Cl.botulinum B. Motionless

5. Cl.histolyticum D. Toxins cause complete melting

D. Cause a violation of swallowing, breathing,

Topic: ANAEROBS.

TICKET #2

1. Name the wrong answer in microbiological diagnostics

wound anaerobic infection:

1. Hemolysis reaction

2. Bacteriological examination

3. Isolation of pure culture and identification

4. Infection of white mice

5. Neutralization reaction

2. Cultivation of Clostridium tetanus:

1. Grow well in alkaline media

2. Strict aerobes

3. Form a film on alkaline broth

4. In a high column of agar, they form colonies in the form of fluffs

5. Do not grow on Kitt-Tarozzi medium

3. Morphological identification of the causative agent of tetanus is carried out according to:

1. Arrangement dispute

2. Formation of a lethal toxin

3. Breakdown of sugars to acid

4. Hemolysis on blood agar

5. Tinctorial properties

4. For laboratory diagnosis of botulism use:

1. Neutralization reaction on white mice

2. Agglutination reaction

4. Allergic test

5. Ascoli reaction

5. Which of the indicated microorganisms, indicated by numbers

correspond to the signs indicated by the letters:

1. Cl.tetani A. Oval-shaped spores

2.Cl. botulinum B. Round-shaped spores

B. A microbe resembles a tennis racket

D. Type of drumstick

D. Gram-positive

Topic: ANAEROBS.

TICKET #3

1. Uncharacteristic for Cl.perfringens:

1. Obligate anaerobes

2. Form spores

3. Sanitary-indicative microorganisms

4. Gram negative

5. Causative agents of gas gangrene

2. Features of the causative agent of tetanus:

2. Have O- and H-antigen

3. Have a centrally located spore

4. Possess saccharolytic enzymes

5. Monotrichus

3. For the treatment of tetanus use:

1. Anatoxin

2. Antitoxic serum

3. Bacteriophage

4. Antimicrobial serum

5. Specific gamma globulin

4. For the prevention of botulism use:

1. Anatoxin

2. Polyvalent antitoxic serum

3. No specific prophylaxis

4. Food preparation control

5. Gamma globulin

5. The pathogenicity of the causative agent of tetanus is associated with the action of:

1. Neuraminidase

2. Exotoxins

3. Plasmacoagulase

4. Adhesins

5. Endotoxin

Topic: ANAEROBS.

TICKET #4

1. Cl.perfringens is characterized by:

1. Proteolysis of gelatin

2. Intensive coagulation of milk

3. Absence in the intestines of a healthy person

4. Type of drumstick

5. Formation of alpha-toxin with a lethal effect

2. Clostridia tetanus (name the wrong answer):

1. Have terminal spores

2. Gram positive

3. Form a capsule

4. Perithriches

5. On blood agar - hemolysis

3. For the prevention of tetanus, apply:

1. Anatoxin

2. Antitoxic serum

3. Bacteriophage

5. Antimicrobial serum

4. For the treatment of botulism use:

1. Bacteriophage

2. Antimicrobial serum

3. Polyvalent antitoxic serum

4. Antibiotics

5. Autovaccine

5. The pathogenesis of tetanus is characterized by all of the following, except:

1. Develops when receiving stab wounds

2. Cl.tetani spores germinate, microorganisms multiply

3. Toxins enter the blood

4. Affect the nervous tissue

5. Blockade of the motor neuron occurs

Topic: ANAEROBS.

TICKET #5

1. The causative agents of gas anaerobic infection include all

the following, except:

2. Cl. perfringens

3. Cl.histolyticum

2. The characteristics of antitoxic immune sera are not

applies to:

1. Obtained by immunization with toxoid

2. Used for medicinal purposes

3. Obtained by immunization with live microbes

4. Used for prophylactic purposes

5. Dosed in antitoxic units

3. For Clostridium botulism is uncharacteristic:

1. Gram-positive stain

2. Antigenic heterogeneity

3. Shape of drumsticks

4. Formation of exotoxin

5. High lethality

4. Among the pathogens listed in the left column, there are

one in connection with four of the five given in

right column. The answer must be written, indicating under what

the number indicates the pathogen corresponding to these four

signs and under what letter is indicated the answer that does not have

relation to this pathogen:

1. Cl.perfringens A. Large sticks

2. Cl.tetani B. Has a terminal spore

4. Cl.histolyticum D. Gram-positive

5. For the pathogenesis of botulism is uncharacteristic:

1. Toxin enters the gastrointestinal tract and persists up to 15 hours

2. Circulates in the blood, damaging the capillaries

3. Double vision

4. Spasms of masticatory muscles

5. Damage to the nuclei of the brain

Topic: ANAEROBS.

TICKET #6

1. The mechanism of aerobinosis is associated with the absence of:

1. Cytochrome oxidase

2. DNases

3. Catalase

4. Peroxide desmutase

5. Desmolases

2. Prevention of wound anaerobic infection consists in

usage:

1. Timely and complete surgical care

3. Antitoxic serum

4. Antimicrobial serum

3. Botulism sticks are characterized by the formation of:

1. Hyaluronidase

2. Plasmocoagulase

3. Neurotoxin

4. Tetanospasmin

5. Endotoxin

4. An injured person with a soil-contaminated wound needs to urgently

inject anti-tetanus antitoxic serum. Specify

under what conditions can you enter it:

1. Preliminary serum test is positive

2. With the introduction of serum, manifestations of anaphylactic shock begin

3. Preliminary serum test is negative

5. In a deep column of agar, Cl.perfringens forms colonies in the form:

1. Lentils

2. Lumps of cotton wool

3. Snow flakes

4. Black column

5. Mucous column

Topic: ANAEROBS.

TICKET #7

1. For the cultivation of pathogenic anaerobes, the following media are used:

1. Yolk-salt agar

2. Wilson-Blair medium

3. Medium Bordet-Gangu

4. Leffler medium

2. For the treatment of wound anaerobic infection, use:

1. Antibacterial serum

2. Antibiotics

3. Bacteriophages

4. Antitoxic serum

5. Autovaccine

3. The pathogenesis of botulism is associated with:

1. Absorption of the toxin into the intestinal mucosa

2. Action of endotoxin

3. Damage to the organ of vision - accommodation disorder, double vision

4. Damage to the medulla oblongata

5. Absence of toxin in the blood

4. A worker who was injured during earthworks with damage

outer covers. 3 days later, during the bandaging, he

found symptoms suggestive of gas gangrene.

Name the diagnostic methods of gas anaerobic infection:

1. Neutralization reaction

2. Ermolyeva's method

3. Color test

4. Biological method

5. A patient was admitted to the surgical department with a torn, crushed

wound. To prevent the development of tetanus, you must enter:

2. Anti-tetanus serum

3. Tetanus toxoid

4. Penicillin

5. Cephalosporin

Topic: ANAEROBS.

TICKET #8

1. Spore gram-positive anaerobic rods

are:

5 Campylobacter

2. The pathogenesis of gaseous anaerobic infection depends on:

1. The nature of the injury

2. Presence of endotoxin

3. The nature of the wound

4. Age of the patient

5. Actions of toxins and enzymes

3. The mechanism of action of botulinum toxin is related to:

1. With the ability of the toxin to spread through the peripheral nerves

2. With toxin damage to motor nerves

3. With inhibition of Ca-dependent release of acetylcholine

4. With the blockade of the functional activity of the neuron

5. With the development of a long incubation period

4. Botulinum toxin most often accumulates in:

1. Canned mushrooms

2. Homemade canned fish

3. Homemade ham

4. Dairy products

5. The pathogenicity of the causative agent of botulism does not depend on:

1. Lethal toxin

2. Tetanospasmin

3. Neurotoxin

4. Hemagglutinin

5. Toxic protein - carrier of hemagglutinin

Topic: ANAEROBS.

TICKET #9

1. Food poisoning

2. Coagulative necrosis of healthy tissue

3. Swelling of tissues with bloody foamy fluid

4. Thrombosis and vascular destruction

5. Damage to the motor centers of the spinal cord

2. Natural habitat of Clostridium anaerobic wound

infections are:

1. Human upper respiratory tract

2. Rodents

4. Animal intestines

3. Features of tetanus disease:

1. Characterized by a relapsing course

2. Tonic contractions of masticatory and facial muscles appear

3. Leave behind a short antitoxic immunity

4. Mortality in the disease is low

5. Runs without cramps

4. A man and a woman with a severe headache were taken to the hospital.

pain, bloating, nausea, vomiting. The patients also had

complaints of double vision, impaired swallowing. the day before

in the evening, both ate canned homemade eggplants

cooking. What microorganism could cause this

disease:

3. Bac.anthracis

5. Cl. perfringens

5. Anti-tetanus serum:

1. Derived from exotoxin

2. Derived from the blood of a horse hyperimmunized with tetanus toxoid

3. Neutralized with formalin

4. Not used for treatment

5.Used for culture identification

Topic: ANAEROBS.

TICKET #10

1. Main properties of Cl.histolyticum:

1. Spread by contact

2. Grow only in aerobic conditions

3. Form beta-toxin-histolisin

4. Form endotoxin

5. Form alpha-toxin with lethal and necrotic action

2. Accelerated diagnosis of gas anaerobic infection:

1. Ermolyeva's method

2. Gas-liquid chromatography

3. Detects Clostridia

4. Neutralization reaction

5. Biological method

3. The pathogenesis of tetanus is associated with:

1. Action of toxins

2. Spread of the disease through the bites of wild animals

3. Damage to muscle tissue

4. Damage to the respiratory centers

5. The introduction of the pathogen through intact skin

4. To confirm the diagnosis of botulism, you must:

1. Set up the precipitation reaction

2. Conduct a microscopic examination

3. Take water for research

4. Examine the mucus from the pharynx

5. Detect toxin in RPHA

5. Neurotoxin has the ability to:

1. Affect the nervous system

2. Agglutinate red blood cells

3. Cause hemolysis of erythrocytes

4. Has all the listed properties

5. Does not have any of the listed properties

Table of contents of the subject "Sanitary-bacteriological research.":

Nonspecific microflora of food products. Sanitary and microbiological analysis of food quality.

Nonspecific microflora of food products, accidentally falling on food products from the environment. It consists of saprophytes, pathogenic and opportunistic microorganisms, as well as species that cause food spoilage. Many food products contain abundant saprophytic microflora, which causes the formation of various biocenotic relationships.

Presence of some saprophytes contributes to the development of biochemical processes that are natural for the length of the food product, on which its quality and often safety depend as a result of antagonistic resistance to pathogenic bacteria that enter the products. The degree of contamination by extraneous microflora depends on many factors: the correct preparation of the food product itself, its transportation, storage, post-processing technology and, at all stages, compliance with the sanitary regime.

Most often studied two main indicators- the presence, as well as the degree of contamination of products with microorganisms and the presence of pathogenic microorganisms. The detection of pathogens is certainly more accurate, but also more time-consuming, therefore it is used only in the primary processing of meat, as well as in some analyzes of milk, meat products and canning production control. The study has three goals.
1. Raw material quality control used in the production of food products and assessment of the sanitary and hygienic conditions of their manufacture.
2. Control of food storage regimes and assessment of sanitary and hygienic conditions for their transportation and sale.
3. Control on ensuring epidemic food safety.

When conducting research, use qualitative and quantitative methods. Qualitative methods determine the nature of technological microflora and causative agents of food spoilage. Quantitative methods in combination with other indicators determine the shelf life and sale of products. The total number of microorganisms is examined in 1 g or 1 cm3 of the product by the method of multiple dilutions. Specific species are determined using specific tests.

Microbiological indicators for milk and dairy products

It should be remembered that on the nature of microbial contamination affect the physicochemical properties of products. Most microorganisms do not survive well in foods with very low and high pH values. They multiply especially abundantly in products with a liquid and semi-liquid consistency. In dense, especially dry or powdery products, the conditions for the reproduction of microbes are difficult and in them they are located in “nests *. Some features of the technology of their production and storage affect the contamination of food products.
mechanical processing(production of minced meat, mashed potatoes, etc.) increases the likelihood of contamination and promotes a homogeneous spread of microorganisms throughout the product.
Chemical processing(salting, pickling) contributes to a sharp decrease in the number of microorganisms. Often, salty foods are additionally smoked, which further reduces the contamination.
The growth of microorganisms is significantly affected temperature regime of their production and storage. An increase in temperature has a more adverse effect on microbes than a decrease, so the effect of high temperatures is widely used for food processing.

Hygienic standards for microbiological indicators include control over 4 groups of microorganisms.
SPM, which include mesophilic aerobic and facultative anaerobic microorganisms - MAFAM (giving growth after incubation at 30 "C for 72 hours with a deep seeding method) and BGKP.
Opportunistic pathogens, which include E. coll, Staphylococcus aureus, Bacillus cereus, Proteus and sulfite-reducing clostridia.
pathogenic microorganisms primarily salmonella.
Microorganisms that cause food spoilage, primarily yeasts and molds.

Microbiological indicators for meat

For different groups food raw materials and foodstuffs there are specific GOSTs for these products. In the absence of GOSTs, hygienic requirements for the quality and safety of food raw materials and food products are used. Regulation in terms of microbiological quality and safety of food raw materials and food products for most groups of microorganisms is carried out according to an alternative principle, that is, the mass of the product is normalized, in which the content of CGB, most opportunistic microorganisms, as well as pathogenic microorganisms, including salmonella, is not allowed. In other cases, the standard reflects the allowable amount of CFU in 1 g (ml) of the product.

Of particular importance is sanitary and bacteriological control over the production of canned food. Canned food - food products packaged in hermetically sealed containers and preserved by heat treatment or combined methods. Canning production aims to create food products that retain high nutritional properties for a long time and at the same time are safe for the health of the consumer. Food products prepared for the manufacture of canned food contain a wide variety of species and quantity of microorganisms originating from the microflora of raw materials and various sources. Regime thermal sterilization kills microorganisms in the canned product, and hermetic sealing of cans excludes the penetration of microorganisms inside. In most cases, canned food is made from products of different quality, and in almost every batch of canned food, some of the cans turn out to be non-sterile. This is due to the fact that among the many microorganisms, taking into account the heat resistance of which the sterilization regime is established, there are also more heat-resistant species. They make up the residual microflora of canned food. If spore-forming microorganisms are unstable to heat, then spores of meso- and thermophilic bacilli and clostridia are particularly resistant to high temperatures (from 115 to 130 ° C). Compliance with the specified storage conditions for canned food prevents the development of residual microflora weakened after sterilization, and canned food remains benign (in this case they are called industrially sterile).

Among the residual microflora of canned food the following are most often found.
mesophilic bacilli: Bacillus subtilis group (I subtilis, B. pumilus, B. licheniformis), Bacillus cereus group (B. cereus, B. anthracis, B. megaterium, B. thuringiensis); Bacilluspolymixa group (B. polymixa, B. macerans, B. circulans).
Bacteria of the genus Lactobacillus.
Clostridia.
Yeast.
mold mushrooms.

Microbiological indicators for sausages

depending from the heat treatment mode and pH values, canned products are divided into groups: A, B, C, D, E. This division allows microbiological research to be carried out in a certain direction. Depending on the purpose, canned food groups are examined for:
industrial sterility,
causative agents of spoilage of canned food,
pathogenic microflora according to epidemiological indications.

Food products are most susceptible to microbial spoilage due to their favorable chemical composition and high water content.

The composition of the microflora depends on the sanitary condition of the enterprise, the conditions of its production, transportation, storage, and sale.

Types of food spoilage:

• mucus;

  acid fermentation;

  pigmentation;

• rancidity;

  self-maturation;

  microbiological diseases;

  swelling.

Microflora of meat and meat products.

Meat is a good nutrient substrate and spoils quickly. In ext. there are no microbes in the layers of meat of a healthy animal after slaughter.

The microflora of the meat surface depends on:

animal skins;

slaughter conditions;

primary processing of the carcass;

touching with contaminated tools;

air purity.

For 1 cm 2 there can be 10 2 - 10 3 m / o.

Meat can be infected with Gram. (gr -) and gr + BGKP, lactic acid, yeast, mold.

Meat can be contaminated with toxic bacteria.

Microbes penetrate into the meat through the blood and mimfat. vessels.

Glaciation is expressed in the formation of a continuous layer of mucus on the surface of the meat bone. It occurs in conditions of high humidity.

Acid fermentation.

Often occurs due to poor bleeding of the animal.

Dark spots.

Sausage mince is stronger than all meat products.

Microbiology of eggs.

Eggs are good nutrient substrates for m/o.

Fresh eggs come from healthy birds.

Eggs: table and diet.

The main pathogens for the microflora of eggs are: Escherichia coli, staphylococcus aureus, moldy fungi.

With prolonged or improper storage, the integrity of the egg shells is violated and it may undergo microbiological deterioration.

Ammonia and hydrogen sulfide accumulate inside the egg. Often, the protein may not be realized with the yolk.

Salmonemia can be found in waterfowl eggs.

Milania contains a significant amount of microbes, so milania breeding is best decommissioned. within a few hours.

Microflora of milk and dairy products.

The quantitative and qualitative composition of the microflora of milk is diverse and depends on the frequency of the skin of the animal, milk, milking machines, air and the frequency of the premises. In milk obtained even in unsanitary conditions, there can be up to a thousand cells per 1 ml 2. These are mainly staphylococci, lactic streptococci, there may be bacteria of the Escherichia coli group (BCG), pathogens of infectious diseases.

Most bacteria in summer and autumn. Fresh milk contains substances - laptins, which in the first hours of their life, delaying the development of infectious diseases in milk.

The period of time during which the bactericidal properties of milk are preserved is called the bactericidal phase.

The bactericidal activity of milk decreases over time, the higher the temperature in milk, the more bacteria. When spoiled, curd products will swallow, become mucilaginous, acquire a sour smell.

Kefir and curdled milk are stratified, and an unpleasant smell prevails.

Microbiology of fruits and vegetables.

Fruits and vegetables are usually inseminated with microbes. They are living organisms and even in suspended animation they breathe and evaporate water.

As the structure of the fruit deteriorates appearance, loss of taste and nutritional value. The resistance of microbes is explained by the fact that:

1) high acidity;

2) the presence of glycosides;

3) essential oils;

4) tannins;

5) phytoncides;

An important role is played by harmful pathogens formed on the surface of fruits and vegetables. The microflora of sauerkraut is represented by lactic acid bacteria. In the deep layers, butyric acid bacteria can develop.

Microflora of grain and flour.

The microflora is represented by bacteria and moldy fungi, much less yeast, fungal spores are constantly found, which retain their viability for years.

Microflora of oysters

is formed due to the ingress of microbes from sea water or from the hands of equipment personnel.

Mollusks, due to their high content of water and complex proteins, are even more vulnerable to decay.

Possible cases of typhoid fever and digestive poisoning as a result of eating them raw.

SUBJECT: MORPHOLOGY OF THE BODY OF A HEALTHY PERSON

In a broad sense - the doctrine of the structure of the human body in connection with its development and vital activity; includes human anatomy, embryology and histology. 2) In a narrow sense, a branch of anthropology that studies variations in gender, age, ethno-territorial, constitutional, professional and other features of the human body, as well as its individual parts and organs. Methods of morphological research are used in ethnic anthropology and in the study of Anthropogenesis. Without morphological data, it is impossible, for example, to correctly determine the degree of similarity and difference between human races, to understand the history of their formation, it is impossible to assess the relationship between modern man and his fossil ancestors. M. hours are usually divided into two subsections: merology, or anatomical anthropology, which studies the variations and connections of individual organs and tissues, and somatology, which studies the variability and dependencies of the signs of the structure of the entire body of a living person. In merology, the integuments of the human body, the outer parts of the sense organs, the entrails, teeth, blood vessels, muscles, the skeleton and skull, and the brain are usually considered. The subject of somatology is the analysis of total body dimensions (body length and weight, chest circumference, body surface and volume) and their ratios, body proportions, external forms of its individual parts, sexual characteristics, some blood characteristics, constitution features, etc. In the 1960s–1970s great development was received by age M. h., especially in connection with a problem of acceleration (See. Acceleration). The introduction of methods of physical and chemical analysis into the practice of morphological research makes it possible to obtain data on the composition of the body, i.e. about the tissue components that make up the body of a living person. We also study the relationship of morphological features with biochemical, physiological, endocrinological characteristics, the genetics of morphological features, the influence of environmental factors on the human morphotype. Morphological data are widely used in anthropological standardization and ergonomics, for example, in the construction of size and height standards to maximize the satisfaction of the population with consumer goods, as well as for the rational arrangement of the workplace, etc.

SUBJECT: DISTRIBUTION OF M/O IN NATURE

The relationship of microorganisms with each other and with the environment ecology. The basic unit in ecology is ecosystem. It includes both biological and abiotic components. Biotic Components constitute a community of organisms, or biocenosis. The sizes of microbial ecosystems are very diverse. It can be, for example, a pond, a lake or a human body.

The natural habitats of most organisms are water, soil and air. In habitats, microorganisms form microcenoses communities with specific and often unusual relationships. Each microbial community in a particular cenosis forms specific autochthonous microorganisms usually found in them. In natural biocenoses (soil, water, air), only those microorganisms that are favored by the environment survive and multiply; their growth stops as soon as environmental conditions change.

Dysbiosis

Dysbiosis is a qualitative and quantitative violation of the ecological balance between microbial populations in the composition of the microflora of the human body. Dysbiosis occurs when exposed to destabilizing factors, such as the irrational use of broad-spectrum antibiotics, antiseptics, a sharp decrease in the body's resistance due to chronic infections, radiation, etc.
With dysbiosis, antagonist microbes are suppressed, which regulate the composition of microbial biocenosis and the reproduction of opportunistic microorganisms. In this way, there is an increase and spread of microorganisms from the genera Pseudomonas, Klebsiella, Proteus, which are the cause of nosocomial infections, yeast-like fungi Candida albicans, causing candidiasis, E. coli, which is the causative agent of colienteritis, etc.
For the treatment of dysbiosis, eubiotics are used, preparations obtained from living microorganisms - representatives of the normal microflora of the human body. These drugs include colibacterin (live bacteria of Escherichia coli, strain M-17), bifidumbacterin (suspension of live B. bifidum, strain n 1), lactobacterin (suspension of live strains of Lactobacterium), bifikol (a complex preparation consisting of a suspension of live bifidumbacteria, strain n 1 and Escherichia coli, strain M-17).

Food microflora

Many food products are a favorable environment not only for preservation, but also for the reproduction of microorganisms.
The entire microflora of food products is conditionally divided into specific and nonspecific.
TO specific microflora include strains of microorganisms used in the process of technological production of food (lactic acid products, bread products, beer, wine, etc.).
TO nonspecific microflora refers to random microflora that enters food products during their preparation, delivery, processing and storage. The source of these microbes can be raw materials, air, water, equipment, animals, people.
Infection of food products with microorganisms can lead to food poisoning and other diseases in humans. Microbiological criteria for food safety are divided into four groups:

Sanitary indicative microorganisms: BGKP, bacteria of the genus Escherichia, Klebsiella, Citrobacter, Enterobacter, Serratia are taken into account.

Potentially pathogenic microorganisms: coagulase-positive staphylococci, bacteria of the genus Proteus, sulfite-reducing clostridia, B. cereus.

Pathogenic microorganisms, including salmonella.

Microorganisms - indicators of the microbiological stability of the product (yeast, mold fungi).

Sanitary and bacteriological examination of food products

Sampling.

Sampling is carried out sterile, with sterile devices, in sterile dishes. Samples are placed in the appropriate container, sealed. Transportation is carried out in cooler bags as soon as possible.
Sanitary and microbiological assessment of food products includes the determination of the total microbial number and titer of sanitary indicative microorganisms.

Determination of the total microbial number (TMC)

TMC - the total number of microorganisms contained in 1 g (cm 3) of the product. To determine it, use the method of multiple dilutions.
Multiple dilution method. In the study of dense substrates, the sample is crushed in a homogenizer or ground in a mortar with quartz sand and the initial suspension is prepared at a dilution of 1:10. A series of subsequent dilutions is prepared from the obtained suspension or initial liquid material so that from 50 to 300 colonies grow in agar when the last two dilutions are sown on a Petri dish. From the last two dilutions, 1 cm 3 is added to the cup and poured into 10-15 ml of molten and cooled to 45 ° C MPA. The plates are incubated at 37°C for 48 h, and the number of grown colonies is counted. TMC is determined taking into account the dilution of the test material.
The method of limiting dilutions (titer). From the initial liquid material, a series of tenfold dilutions is prepared until the presence of one bacterial cell can be assumed in the last test tube. Sowing is done in a liquid selective medium, followed by the isolation of microorganisms on a solid nutrient medium and the study of their characteristics.
The titer is taken as the smallest amount of substrate in which one individual of the desired microorganism is found.

Determination of sanitary-indicative microorganisms

Sanitary-indicative microorganisms characterize the product in terms of epidemic danger.
The main sanitary-indicative microorganisms are BGKP and for quantitative accounting they use methods for determining the amount and titer. At the same time, the quantity is understood as the determination of the most probable number (MPN) of BGKP in a unit of mass or volume of the product.

Definition of HF BGKP.

To determine the NPs from a liquid product or an initial dense suspension, dilutions are sequentially made
10 -1 , 10 -2 , 10 -3 , of which 1 cm 3 is inoculated into three test tubes with Kessler's medium for each dilution. After 24 hours of incubation at 37°C, changes in the color of the medium and gas formation are recorded in the test tubes. Depending on the number of germinated test tubes, NPs of coliform bacteria are determined.

Determination of the titer of BGKP

Tenfold dilutions of the analyzed material are prepared and sown on Kessler's medium to identify the smallest amount of the product in which E. coli is present. The inoculations are thermostated at 43°C for 18-24 hours. Each tube is inoculated onto Petri dishes with Endo's medium in such a way as to obtain the growth of individual colonies. The inoculations are incubated at 37°C for 18-24 hours, after which smears are made from the grown colonies and stained according to Gram. When gram-negative rods are detected in smears, the colonies are subcultured on Hiss media with glucose. The presence of gas formation in test tubes with crops indicates the presence of BGKP.
The titer is set according to the smallest amount of the product in which BGCPs are found or according to standard tables.
In assessing food products by microbiological indicators, it is necessary to take into account the possibility of detecting pathogenic and opportunistic microorganisms. Food products are analyzed for the presence of salmonella, sulfite-reducing clostridia, staphylococci, and proteus. In a broader study, products are examined for fungal flora.
To study for Salmonella, a suspension is prepared from the analyzed products and inoculated on accumulation media (selenite, magnesium chloride broths). After a daily incubation at 37 ° C, re-seeding is carried out on Endo, Levin, Ploskirev media or bismuth-sulfite agar. Further, the colonies are identified by taking into account the growth characteristics on the media of Giss, Ressel, Olkenitsky and in the agglutination reaction with monoreceptor sera.
To identify sulfite-reducing clostridia, the test material is inoculated into 2 test tubes with Kitt-Tarozzi, Wilson-Blair or casein-mushroom medium. One test tube is heated at 80 °C to destroy the accompanying microflora. The inoculations are incubated at 37°C for 5 days. In the presence of characteristic growth, it is sufficient to ascertain the specific microflora in smears and, if necessary, to check toxin formation in a bioassay on white mice.
To detect staphylococci, the test material is inoculated on yolk-salt agar. The inoculations are incubated in a thermostat for 24 hours. Suspicious staphylococcal colonies are stained by Gram, they are reseeded onto milk agar, and the isolated culture is further identified.
To identify the proteus, the test material is sown on a slant agar by the Shukevich method. After daily incubation, smears are made from the upper edge of growth and, if they contain gram-negative polymorphic bacteria, a conclusion is made about the isolation of Proteus, if necessary, biochemical and antigenic typing is used.

Microflora of medicinal plants.

Microorganisms are constant companions not only of humans and animals, but equally of higher plants, including those used as medicinal raw materials. Microorganisms settle and lead an active lifestyle, both on the surface and inside the green parts of plants, their roots, seeds, fruits. A wide variety of plants are used to prepare medicines, and workers in pharmacies, pharmaceutical factories and plants must ensure the safety of medicinal raw materials from microbial spoilage.
All microorganisms inhabiting medicinal plants can be divided into two groups:

representatives of the normal microflora of plants;

phytopathogenic microorganisms - pathogens of plant diseases.

The normal microflora of plants is represented by rhizospheric and epiphytic microbes. The zone of soil in contact with the root system of plants is called the rhizosphere, and the microorganisms that develop in this zone are called rhizosphere. Two types of rhizosphere are conditionally distinguished: near and distant.
The nearest one is located directly on the surface of the roots and is extracted along with them, the distant one begins at a distance of several millimeters from the roots and spreads within a radius of 50 cm from them. The number of microorganisms in the near and distant rhizosphere is different: on the surface of the roots there are from 50 million to 10 billion, at a distance of 15 cm from the roots up to 5 million in 1 g of soil. The number of microorganisms in the rhizosphere is 100 times greater than in the soil where plants do not grow, which is associated with the release of various nutrients by plant roots. In turn, soil microbes can have a beneficial effect on plant life, which is due to:

mineralization of organic substances and plant residues;

the formation of vitamins, amino acids, enzymes and other growth factors that enhance enzymatic processes in plants and enhance root nutrition and more vigorous plant metabolism;

antagonistic role against phytopathogenic microorganisms.

The qualitative and quantitative composition of the rhizosphere microflora is specific for each plant species. The bulk of the basal microflora is represented by non-spore-bearing gram-negative bacteria of the genus Pseudomonas, mycobacteria and fungi, mainly basidiomycetes, less often phycomycetes, ascomycetes. These fungi form a symbiosis with the roots of plants, including medicinal ones, called mycorrhiza. Depending on the morphological features of the cohabitation of fungi with plants, ectotrophic and endotrophic mycorrhiza are distinguished. Ectotrophic - associations in which the fungus does not penetrate the roots, but settles on their surface, forming a kind of cover from the mycelium. In endotrophic mycorrhiza, the mycelium of the fungus is located in the cells of the bark of plant roots, where it forms clusters in the form of balls.
Mycorrhiza is considered as a symbiotic cohabitation of distant organisms. This cohabitation is especially favorable for the development of plants:

increases the absorbing surface of the roots due to the branching of the hyphae of the fungus;

fungi decompose nitrogen-rich organic compounds with their enzymes, providing plants with amino acids, minerals and water;

mycorrhizal fungi supply plants with growth substances.

Plants, in turn, secrete a number of growth substances that stimulate the development of the fungus. In addition, fungi receive carbohydrates from plants, which serve as a source of energy.
epiphytic microflora. Epiphytic is the microflora located on the surface of the aerial parts of plants. In terms of its qualitative composition, it is rather monotonous and its typical representatives are Pseudomonas furbicola aurum - gram-negative short mobile rods that form golden colonies on MPA; Pseudomonas fluorescens are polymorphic gram-negative rods with polar flagella that fluoresce on MPA and MPB. Less common are spore bacteria Bacillus mesentericus, Bacillus vulgatus, non-spore lactic acid bacteria E. coli, molds and yeasts.
Epiphytic microorganisms are antagonists of phytopathogenic bacteria, thereby protecting plants from diseases.

Phytopathogenic microorganisms

Infectious plant diseases are caused by phytopathogenic bacteria. Infection of plants occurs through infected seeds, soil, ground and rain water, insects. The main source of infection is the soil, as it may contain the remains of undecayed, completely diseased plants.
Phytopathogenic microorganisms can relatively easily penetrate plants through natural formations (lenticels, nectaries, glands, root hairs) and artificial damage, even insignificant scratches. Some microorganisms are able to produce enzymes that hydrolyze the plant cuticle and facilitate the introduction of the pathogen.
Once in the plant and reaching a critical concentration in quantitative terms, microorganisms cause diseases called bacterioses. There are general bacterioses - the defeat of the entire plant due to the spread of the pathogen in the vascular system; and local or focal - lesions on leaves, trunks, branches, roots and rhizomes arising from the intracellular spread of the microbe.
From the beginning of infection to the moment the symptoms of the disease appear in the plant, an incubation period passes, the duration of which is different and depends on many factors: temperature, humidity, light, nutrition, etc.
Based on the combination of anatomical and physiological changes, the type of plant disease is determined:

Gum flow, gum flow, mucus flow. Most often caused by bacteria of the genus Erwinia and fungi (class Ascomycetes), most are observed in deciduous and coniferous trees.

Dry and wet rot. At the same time, individual parts of the tissues and organs of the plant are softened and destroyed due to the vital activity of bacteria (genus Pectobacterium) and fungi (class Ascomycetes and Fungi imperfecti).

Powdery mildew. A white coating appears on the leaves and shoots, which is a consequence of the reproduction of fungi (class Ascomycetes).

Yellowing, wilting, drying. This disease is most often caused by fungi (Fungi imperfecti), less often by bacteria (genus Corynebacterium), in some cases the disease is non-infectious.

Black. A black film appears on the leaves and shoots due to the development of marsupial and imperfect fungi or bacteria of the genus Erwinia.

Burn. Leaves, young shoots, flowers, fruits turn brown, blacken. Burns are caused by bacteria of the genus Erwinia.

Spotting. Some bacteria (genus Pseudomonas), fungi (class Ascomycetes and Fungi imperfecti) cause the formation of spots of different colors, shapes, sizes on leaves, seeds and fruits.

Tumors. Local increase in the volume of trunks, branches, roots, rhizomes in the form of outgrowths, swellings, thickenings due to cell hyperplasia. These diseases are caused by bacteria (genus Agrobacterium), fungi and mechanical damage.

Ulcers. They appear as depressions, often surrounded by an influx. Caused by bacteria (genus Erwinia), fungi, mechanical damage, low temperature.

Mosaic of leaves. Pale colored spots appear on the leaves, alternating with normally colored areas. Called by viruses.

Witch brooms. The formation of shoots from dormant buds as a result of the development of bacteria (genus Rhisobium), fungi (class Ascomycetes) and viruses.

Deformation. It manifests itself in a change in the shape of plant organs (curvature of shoots, leaf curl, dwarfism) due to damage by fungi (class Ascomycetes and Fungi imperfecti), viruses (family Reoviridae).

It is essential that in diseased plants metabolic processes noticeably deviate from the norm, up to qualitative changes in cellular structures, which leads to a violation of the chemical composition of tissues and a decrease in the content of active principles in medicinal plants, and their use as raw materials in pharmaceutical and factory conditions becomes impossible.
The plant organism has protective mechanisms that counteract the introduction and reproduction of phytopathogenic bacteria. These include features of integumentary tissues, high acidity of cell sap, the formation of biologically active substances - phytoncides that inhibit the development of microbes.
Prevention measures. They consist in disinfection of seeds and planting material, disinfection of the soil, spraying of plants with chemicals, destruction of plant residues, carriers of pathogens, removal of diseased plants and isolation of healthy ones.
The existing classification of phytopathogenic bacteria is imperfect, their genus and species are not always defined.
Phytopathogenic bacteria belong to the genera: Erwinia, Pseudomonas, Xanthomonas, Corynebacterium, Pectobacterium, Rhisobium (Table 5).
Viruses are known to cause more than 20% of plant diseases. Most viruses belong to the Reoviridae family, Phytoreovirus, Fijvirus genera.
Of the phytopathogenic fungi, two classes should be noted - ascomycetes (Ascomycetes), and imperfect fungi (Fungi imperfecti).

Table 5

Phytopathogenic bacteria - causative agents of infectious diseases of medicinal plants

childbirth	Kinds	Diseases caused
		Burn, wither
		spotting
		Spotting, wilting
	C. insidiosum, C. fasciens	Withering
	P. phetophtorum, P. aroidae
	R. legyminosorum

Introduction

Literature review

1 Soil microflora

1.1 Factors affecting the qualitative and quantitative composition of soil microorganisms

1.2 Physiological groups of microorganisms

1.3 Self-purification processes in the soil

2 Sanitary characteristics of soils

3 Sampling and pretreatment of soil samples for analysis

3.1 Soil sampling

4 Determination of bacteria in soil

Results and discussion

INTRODUCTION

Soil is a mixture of particles of organic and inorganic substances, water and air.

Inorganic soil particles are mineral substances surrounded by a film of colloidal substances of an organic or inorganic nature.

Soil organic particles are the remains of plant and animal organisms, i.e. humus. The soil is abundantly populated by microorganisms, as it has everything necessary for life: organic matter, moisture, protection from sunlight.

In the soil there are all forms of microorganisms that are on Earth: bacteria, viruses, actinomycetes, yeasts, fungi, protozoa, plants.

The total microbial number in 1 g of soil can reach 1-5 billion. 1 ha of soil contains 1 ton of live weight of bacteria, but the number of microorganisms varies in different layers. There are very few microorganisms in the uppermost soil layer (layer < 0.5 cm). At a depth of 1-2-5 cm to 30-40 cm, the number of microorganisms is the highest. In this layer, on average, TMP is 10-50 million per 1 year. In relatively clean soils, this figure is 1.5-2 million per 1 year. Deeper than 30-40 cm, the number of microorganisms decreases, and again there are few of them in deeper layers.

1 SOIL MICROFLORA

1.1 Factors affecting the qualitative and quantitative composition of soil microorganisms

The following factors influence the number and composition of microorganisms:

1. Soil type (tundra, podzolic, chernozem, gray soil).

Chernozem soils are the richest in microorganisms, in which up to 10% of organic matter from the dry weight of the soil.

There are more than 3.5 million microbial cells in 1 g of chernozem soil. The microbial landscape in such soils is influenced by abundant vegetation with a rich root system. The roots secrete protein and nitrogenous substances, mineral salts, organic acids, and vitamins into the soil. As a result, rhizospheres, i.e., accumulations of microorganisms, are created around the roots.

Microorganisms, in turn, affect the biochemical processes in the soil, fertility. Depleted, mountainous and sandy soils are poor in microorganisms. In such soils organic matter is 1% of the dry weight of the soil.

2. Soil moisture.

In wet soils, microorganisms multiply better than in dry ones, but in the soils of peat bogs, despite the large amount of moisture and organic matter (up to 50%), there are few microorganisms, since these soils have an acidic reaction and the antagonistic effect of mosses is manifested in them.

3. Aeration.

Moisture-rich soils are poorly aerated. Under these conditions, anaerobes predominate, and sandy soils are better aerated, so they have more aerobes.

4. Soil temperature.

In warm periods of the year, microorganisms are many times more than in winter. In winter, the development of microorganisms stops, and they die. There are daily fluctuations in the number of microorganisms in the soil. The most favorable temperature is 20-30°C, and at a temperature of 10°C and below, development slows down.

5. Adsorption capacity of soils.

The highest adsorption capacity of soils is observed in mountainous (humus) soils; it depends on the content of silt particles in the soil, the amount of medium and fine dust, and soil pH. These soils are rich in calcium. The nature of the soil also affects the depth of penetration of microorganisms.

In more humid northern soils, the life of microorganisms is, as it were, “pressed” to the surface, and in light, alkaline southern soils, the life of microorganisms is “deepened”. They can be found at depths of 10 m or more.

Microbiology of food products

1. Microbiology of milk and dairy products

2. Microbiology of meat and sausages

3. Microbiology of eggs and egg products

4. Fish microbiology

5. Microbiology of cereals, flour, bread

6. Microbiology of fruits and vegetables

7. Microbiology of canned food

8. Microbiology of culinary products

1. In raw milk, even under hygienic conditions for its production, a certain amount of bacteria is usually found. If the milking conditions are not observed, milk can be abundantly contaminated with microorganisms due to infection with microbes located on the surface of the udder, falling from the ducts of the mammary gland, from the hands of milkers, from milking utensils and equipment, from the air. In combined milk, selected directly from farms, the total number of bacteria ranges from 4.6x10 4 to 1.2x10 6 in 1 cm 3.

The microflora of fresh milk is diverse. It contains bacteria lactic acid, butyric, groups of Escherichia coli, putrefactive and enterococci, as well as yeast. Among them are microorganisms. Able to cause rancidity, foreign tastes and odors, discoloration (blue, redness), ductility. There may also be pathogens of various infectious diseases (dysentery, typhoid fever, brucellosis) and food poisoning (Staphylococcus aureus, allmonella).

Fresh milk contains bactericidal substances - lactenins, which in the first hours after milking retard the development of bacteria in milk, and many of them even die. The period of time during which the bactericidal properties of milk are preserved is called bactericidal phase. The bactericidal activity of milk decreases over time and the faster, the more bacteria in the milk and the higher its temperature.

Freshly milked milk has a temperature of 35 0 C. At 30 0 C, the bactericidal phase of milk with a small initial contamination lasts up to 3 hours; at 20 0 C - up to 6 hours; at 10 0 C - up to 20 hours; at 5 0 C - up to 36 hours; at 0 0 C - 48 hours. At the same holding temperature, the bactericidal phase will be significantly shorter if the milk is heavily contaminated with microbes. So, in milk with an initial bacterial contamination of 10 4 in 1 cm 3, the bactericidal phase at 3-5 0 C lasts 24 hours or more, and with a content of 10 6 bacteria in 1 cm 3 - only 3-6 hours. To prolong the bactericidal phase of milk, it is necessary to cool it as soon as possible to at least 10 0 C.

At the end of the bactericidal phase, the reproduction of bacteria begins and it occurs the faster, the higher the temperature of storage of milk. If milk is stored at a temperature above 10-8 0 C, then already in the first hours after the bactericidal phase, various bacteria begin to develop in it. This period is called phase of mixed microflora.

By the end of this phase, mainly lactic acid bacteria develop, in connection with which the acidity of milk begins to increase. As lactic acid accumulates, the development of other bacteria, especially putrefactive ones, is suppressed. Some of them even die off and come lactic acid bacteria phase. The milk is fermented.

With further storage of milk, with an increase in the concentration of lactic acid, the development of lactic acid bacteria themselves is suppressed, their number decreases. First of all, lactic streptococci die off. Lactic acid sticks are less sensitive to the acidity of the environment and die off more slowly. In the future, yeast and mold growth may occur. These microorganisms use lactic acid and form alkaline protein rampad products; the acidity of milk decreases, putrefactive bacteria can again develop in it.

In milk stored at temperatures below 10-8 0 C, lactic acid bacteria almost do not multiply, which contributes to the development, albeit slowly, of cold-resistant bacteria of the genus Pseudomonas, capable of causing the decomposition of proteins and fats; the milk acquires a bitter taste.

To keep milk fresh, it is cooled at a dairy farm or collection point to temperatures of 6-3 0 C and delivered in a chilled state to processing dairies.

Milk pasteurization is designed to destroy pathogenic bacteria and possibly more complete reduction of the total contamination by bacteria. The efficiency of milk pasteurization depends on the quantitative and qualitative composition of its microflora, mainly on the number of heat-resistant bacteria. Drinking milk is pasteurized at 76 0 C with a holding time of 15-20 seconds. The mode of pasteurization of milk used for the manufacture of fermented milk products is more stringent.

Pasteurization retains a certain amount of vegetative cells of thermophilic and heat-resistant bacteria, as well as bacterial spores. In case of violation of the continuous automated pasteurization cycle (its rupture on the way from the pasteurizer to bottling into containers), milk can be additionally infected with microorganisms. The degree of this secondary contamination of pasteurized milk depends on the sanitary and hygienic conditions of production.

Store pasteurized milk at a temperature below 10 0 C for no more than 36-48 hours from the moment of pasteurization. Flask milk should be boiled before eating.

sterilized milk can be stored for a long time without being subjected to microbial spoilage, since in the process of sterilization its microflora is destroyed.

Sterilized condensed milk produced in the form of canned food. The microflora in this milk should be absent, but spoilage is sometimes observed. It manifests itself more often in the form of bombing (bloating) of cans, caused by heat-resistant, spore-forming, anaerobic bacteria of the genus Clostridium, which ferment lactose with the formation of carbon dioxide and hydrogen and butyric acid bacteria.

Condensed milk with sugar they are also released in hermetically sealed jars, but they will not pull sterilization. The stability of this product is achieved by an increased content of solids, especially a large amount of sucrose. The most common defect of such milk during long-term storage is the formation of "buttons" - seals of different colors (from yellow to brown). The causative agent is more often chocolate-brown mold Catenularia.

Can bombing is sometimes found, caused by yeast fermenting sucrose. At the same time, the sugar content decreases, the acidity increases.

The main dairy products include sour-milk products, butter, margarine, cheeses.

Dairy products play an important role in human nutrition, since, in addition to nutritional value, they have dietary, and some medicinal value. Dairy products are digested better than whole milk, and much faster.

Compared to milk, fermented milk products have an increased shelf life. They are, moreover, an unfavorable environment for the development of many pathogenic bacteria. This is due to their high acidity and the content of antibiotic substances produced by some lactic acid bacteria.

In the conditions of industrial processing of milk in the manufacture of various fermented milk products, it is pre-pasteurized and then fermented with specially selected starter cultures from pure or mixed cultures of lactic acid bacteria. Therefore, the activity of the starter used and the quality of the processed milk are of great importance.

The composition of the starter for the manufacture curdled milk, sour cream and cottage cheese includes lactic acid streptococci and aroma-forming streptococci.

In the manufacture cottage cheese, in addition to sourdough, rennet is used, which activates the process. Sometimes cottage cheese is made from unpasteurized milk. Such cottage cheese is intended only for the manufacture of products that are subjected to heat treatment before use due to the possible reproduction in it of pathogens of food intoxication - staphylococci, which are usually found in raw milk.

When developing kefir they use not pure cultures of microorganisms, but a natural fungal starter - pasteurized milk fermented with the so-called kefir fungus. In the process of fermentation and maturation of kefir, yeast, lactic streptococci, lactic acid bacilli and acetic acid bacteria play a certain role.

Thus, kefir is a product of combined fermentation: lactic acid and alcohol. The alcohol content can be up to 0.2 - 0.6% (depending on the duration of maturation). The resulting carbon dioxide gives the product a refreshing taste. The smell of hydrogen sulfide sometimes appears in kefir. The cause and causative agent of this smell can be putrefactive bacteria. In a clot of kefir, "eyes" can form, which is associated with the excessive development of yeast and aroma-forming bacteria - components of the kefir fungus.

The composition of the leaven for ryazhenka includes thermophilic lactic streptococcus and a small amount of Bulgarian bacillus. Ryazhenka is made from a mixture of milk and cream. The mixture before fermentation is heated to 95 0 C for 2-3 hours, as a result of which it acquires the color and taste of baked milk.

Butter- one of the most important products of milk processing. Butter is made from pasteurized cream. The number of bacteria in them is usually small - from hundreds to several thousand per 1 cm 3. These are mainly spore rods and micrococci.

Microflora sweet cream butter contains residual microflora of pasteurized cream and extraneous microflora, namely, sporeless rod-shaped bacteria and micrococci, among which there are those capable of breaking down milk fat and proteins.

sour cream butter is made from pasteurized cream fermented with pure cultures of lactic acid streptococci. Aroma-forming streptococci are also introduced into the starter culture. Naturally, sour cream butter, compared to sweet cream butter, contains significantly more bacteria, mainly lactic acid, yeast is also present. The number of microorganisms in sour cream butter reaches millions and tens of millions per 1 g. Extraneous microflora is insignificant, its development is delayed by lactic acid, which is formed by lactic acid bacteria.

The most common defect in butter is mold, especially when stored in conditions of high humidity. Molds develop on the surface of the oil in the form of spots of different colors. Sometimes the oil will mold inside the block if there are voids in it that form when the oil is not packed tightly.

Long-term storage of butter at a temperature of -20 to -30 0 C is recommended. At the same time, not only microbiological, but also physico-chemical processes are delayed in it. The type of packaging also matters; oil packed in films made of polymeric materials is preserved better than oil packed in parchment.

Milk margarine It has two types of microflora: a starter microflora used for the fermentation of milk, which is part of margarine, and an extraneous microflora, of non-starter origin. The development of extraneous microflora, which can cause defects in the taste and smell of margarine, is possible mainly only in the water-milk phase of margarine.

Margarine is a highly dispersed emulsion; its water-milk phase is in the form of tiny droplets ranging in size from 1 to 10 microns, which significantly reduces the possibility of reproduction of microorganisms. The low pH value of this margarine phase (pH about 5) is also unfavorable for many bacteria.

Active development of microbes can only be on the surface of the product or in places where condensation moisture accumulates, which occurs during intensive cooling of margarine packaged in moisture-proof packaging.

If margarine is spoiled, it can become rancid, acidic, moldy.

Cheese- a valuable product of milk processing in terms of taste and nutritional properties. The properties of cheese - taste, aroma, texture, pattern - are formed as a result of complex processes, in which the main role belongs to the world's organisms.

Coagulation of milk (coagulation of casein) is carried out by fermenting it with lactic acid bacteria and introducing rennet.

During all the technological stages of cheese production, lactic acid bacteria accumulate in the cheese mass, which become the main microflora of the ripening cheese.

The maturation of cheeses proceeds with the active development of microbiological processes. In the very first days of ripening, lactic acid bacteria rapidly develop in the cheese, the number of their cells in 1 g of cheese reaches billions. Bacteria ferment milk sugar with the formation of lactic acid, and some also produce acetic acid, carbon dioxide, hydrogen. The accumulation of acids inhibits the development of extraneous microflora.

When ripening hard cheeses Dutch the main role belongs to lactic acid streptococci. In the microflora of ripening Swiss-type cheeses, thermophilic lactic acid sticks predominate, mainly cheese sticks, which play a leading role in the lactic acid process. Thermophilic streptococci also take part in cheese ripening. After milk sugar is fermented, the development of lactic acid bacteria stops and they begin to gradually die off.

In the process of maturation of cheeses, changes occur not only in milk sugar. But also milk proteins. In these processes, lactic acid bacteria also play a significant role.

Develop in ripening cheeses and propionic acid bacteria. They ferment lactic acid to form propionic and acetic acids and carbon dioxide.

Propionic and partially acetic acids, as well as some amino acids and their cleavage products, give cheeses their characteristic pungent taste and smell. The accumulation of carbon dioxide and hydrogen in cheeses as a result of the vital activity of lactic acid and propionic acid bacteria cause cheese eyes, which create a cheese pattern.

During the maturation of hard cheeses, especially at the initial stage of the process, bacteria of the Escherichia coli group can actively develop, and at the end of maturation, butyric ones. The growth of these bacteria is accompanied by an abundant release of carbon dioxide and hydrogen, which results in an irregular cheese pattern and even swelling.

There is also such a defect as the bitterness of cheese, due to the development of microorganisms that actively decompose proteins, the resulting peptides have bitterness. This defect can cause some lactic streptococci.

Significantly reduces the quality of cheese an anaerobic spore bacterium of the genus Clostridium putrificum, which has a pronounced activity. At the same time, the cheese softens, its consistency becomes smeared, a putrid smell and an unpleasant taste appear. However, spoilage, especially of hard rennet cheeses, is more often manifested in mold.

When developing soft, so-called mold cheeses In addition to lactic acid bacteria, molds are of great importance, with which cheeses are specially infected. The peculiarity of the taste of these species is due to a change not only in milk sugar and protein substances, but also in milk fat, which is broken down by molds with the formation of volatile fatty acids.

Processed cheeses produced mainly from mature cheeses. Their microlora is mainly represented by spore-bearing bacteria, there are also lactic acid and coli, and streptococci, preserved during the melting of cheese. The number of bacteria in these cheeses is relatively small, thousands of cells per 1 g. During refrigerated storage (up to 5 0 C), no significant changes in the microflora are observed for a long time. At higher temperatures, the number of bacteria increases more or less rapidly depending on the temperature. Butyric acid bacteria are the most dangerous causing swelling of cheeses. To avoid this type of spoilage, the antibiotic nisin is introduced into cheeses.

General bacterial contamination smoked sausage cheeses usually does not exceed hundreds of cells per 1 g. These are mainly spore bacteria. The main type of spoilage of these cheeses is molding.

2. Microbiology of meat and sausage products. Meat is a good nutrient substrate for many microorganisms, in which they find all the substances they need - sources of carbon and nitrogen, vitamins, mineral salts. The pH of the meat also favors the development of micro-organisms, and as a result, the meat spoils quickly.

The muscles of healthy animals are usually sterile. The muscles of sick animals that have undergone starvation before slaughter, severe overwork, may contain microorganisms. In addition to lifetime infection, muscles can be contaminated with microbes after the slaughter of an animal: during the primary processing and cutting of carcasses, from tools, from the hands of workers, etc. Therefore, even freshly processed meat is not sterile and, mainly on the surface, it contains one or another number of microorganisms.

The contamination of freshly processed chilled meat with microorganisms can vary depending on the degree of maturation of the meat, the temperature and humidity conditions of cooling, the sanitary and hygienic conditions of production, etc. The composition of the microflora is diverse. These are mainly aerobic and facultative anaerobic, sporeless, gram-negative rod-shaped bacteria, bacteria of the Escherichia coli group, lactic acid micrococci. In smaller quantities, aerobic and anaerobic spore-forming bacteria, yeasts, and mold spores are found.

Meat can also be infected with toxigenic bacteria, the genus Clostridium, Salmonella. Salmonella often cause intestinal diseases in cattle, after which the animals are bacillus carriers for a long time.

Meat by-products (brains, kidneys, heart, etc.) are usually more contaminated with microbes than meat, and therefore spoil more quickly.

Reproducing under favorable conditions on the surface of the meat, microorganisms gradually penetrate into its thickness.

Chilled meat is a perishable product. Temperature is decisive for the rate of microbial growth and hence for the spoilage of chilled meat. The spoilage of chilled meat can manifest itself in different ways and depending on the storage conditions.

rotting meat starts at the surface and gradually spreads to the depth. At a storage temperature above 5-8 0 С putrefactive processes are caused by aerobic and anaerobic microorganisms. In the initial stages of the process, mainly coccal forms of bacteria are involved, then they are replaced by rod-shaped bacteria. The spoilage of meat at these temperatures occurs very quickly - within a few days.

When storing meat at temperatures below 5 0 C, the composition of its initial microflora gradually changes and becomes more uniform. After a few days of storage, non-spore Gram-negative bacteria of the genus Pseudomonas (up to 80% or more of the entire microflora) show greater activity.

With putrefactive spoilage of meat, its color becomes gray, it loses its elasticity, becomes slimy, softens. First, a sour, and then an unpleasant, putrid smell appears, which intensifies as the process deepens.

slime- the earliest common type of spoilage of cooled and chilled meat, especially if it is stored in conditions of high relative humidity (over 90%). This defect is caused mainly by bacteria of the genus Pseudomonas; often mucus is also caused by micrococci. Mucus is expressed in the formation of a continuous layer of mucus on the surface of the meat. It has been established that abundant mucus formation in these bacteria occurs at temperatures from 2 to 10 0 С; mucus accumulates (albeit slowly) even at -2 0 C.

acid fermentation accompanied by the appearance of an unpleasant sour smell, the formation of a gray or greenish-gray color on the cuts and the softening of the meat. This process can be caused by anaerobic bacteria of the genus Clostridium. Acid fermentation of meat often occurs due to poor bleeding of animals during slaughter, as well as in cases where carcasses are not cooled for a long time.

meat pigmentation- the appearance of colored spots - is associated with the development of pigment microorganisms on its surface. Thus, the development of the “wonderful stick” (Serratia marcescens) leads to the formation of red spots unusual for meat. In the case of the development of non-pigmented non-spore-bearing yeast, a white-gray coating appears on the meat.

mold due to the growth of various fungi on the surface of the meat. Mold development usually begins with the appearance of an easily washable cobwebbed or powdery coating of white. In the future, more or less powerful raids are formed. On chilled meat, many mucor fungi (Mucor, Rhizopus) can develop, forming white or gray fluffy plaques. Black plaque gives Cladosporium, green - appears with the development of fungi of the genus Penicillium, yellowish - with the development of Aspergillus.

In addition, some molds found on meat can produce toxic substances.

The optimal storage conditions for chilled meat are considered to be temperatures from 0 to -1 0 C and relative humidity of 85-90%, but even under such conditions, meat is stored for no more than 10-20 days.

Meat semi-finished products, especially small pieces and minced meat, deteriorate faster. They usually contain more microorganisms than the meat from which they are made.

To prolong the shelf life of chilled meat, it is possible to use means of influencing microorganisms additional to cold: increasing the content of carbon dioxide in the atmosphere, ultraviolet irradiation, ozonation of storage chambers. Significantly increases the shelf life of chilled meat in a nitrogen atmosphere. Under such conditions, mucilage of meat occurs 2-3 times slower than when stored in air.

To increase the shelf life of meat, it is frozen and stored in this form for a long time. During the storage of frozen meat, the microorganisms remaining in it gradually die out, but some, including toxigenic ones, can remain viable. The microflora of frozen meat is dominated by micrococci. At a temperature not higher than -12 0 C, frozen meat is preserved for months, and the growth of microorganisms does not occur on it.

Microflora of poultry meat poultry meat, like cattle meat, is a favorable environment for the development of microorganisms. The species composition of microflora, types of spoilage of poultry meat are similar to microorganisms of meat of slaughtered animals, however, in poultry, especially in waterfowl, salmonella, the causative agents of food toxic infections, can be more common in the muscles.

For the development of spoilage processes, the method of slaughter and cutting of poultry is important.

Half-gutted poultry carcasses are usually more heavily contaminated with microbes than gutted ones. With half-gutting, intestinal rupture often occurs, which contaminates the cavity of the carcass with intestinal microorganisms.

Damage to the skin during the removal of feathers also contributes to infection of the muscles by microbes. The microflora of poultry kept at 1 0 C, by the time the sign of spoilage (foreign odor) appears, consists mainly of aerobic non-spore rod-shaped bacteria, mainly of the genus Pseudomonas (up to 70-75%).

Frozen poultry is stored without microbial spoilage at a temperature not higher than -12, -15 0 C for a long time, for months. On frozen chickens stored for a year at -7-10 0 C, yeasts and molds develop, and at -2.5 0 C - Pseudomonas, bacteria and yeasts.

Microflora of sausages Sausage products are usually eaten without additional heat treatment. Therefore, these products and the technological process of their manufacture are subject to increased sanitary requirements. As a rule, during the manufacture of sausages, the content of microbes in meat increases compared to their original amount. Already during the primary processing of meat (during deboning and trimming), the number of meat microflora significantly increases as a result of its contamination with microbes from the hands of workers, tools, equipment and from the air. The number of microorganisms in meat significantly increases during its grinding, as well as due to the microflora of the auxiliary materials and spices used (if they are not previously sterilized). Practice shows that grinding meat increases its contamination by an average of 10 times.

The contamination of minced meat also depends on the type of meat used. Stuffing minced meat into casings by hand can lead to infection with undesirable microorganisms. The vast majority of these are gram-negative non-sporing rods, micrococci, spore-forming bacteria, bacteria of the Escherichia coli group are found in much smaller quantities.

After stuffing minced meat into shells, boiled and semi-smoked sausages are fried and then boiled; half-smoked sausages are still smoked.

When roasting with hot smoke, the temperature inside the loaf is not more than 40-45 0 С, therefore the number of microorganisms decreases only on the surface of the loaves due to the action of antiseptic substances of smoke and temperature. In loaves of small diameters, the number of bacteria slightly decreases in the thickness. During the cooking of sausages (until reaching 70-72 0 C in the depth of the loaf), the content of microorganisms in sausages decreases by 90-99%, but still quite a lot of them can remain, especially in the depth of the sausage mass. Usually spore-bearing rods and the most resistant micrococci are preserved. Some toxin-forming bacteria may also persist.

After cooking, sausages are quickly cooled to avoid the reproduction of residual microflora in them.

In the process of smoking sausages, the number of bacteria in them decreases.

In the manufacture of smoked (raw-smoked, dry-cured) sausages, prepared minced meat after being stuffed into casings is subjected to maturation. To do this, the loaves are kept at low positive temperatures for several days, after which they are smoked and dried for a long time until the required moisture content of the product (25-35%) is reached.

During the maturation of minced meat, complex physicochemical, biochemical and microbiological processes take place in it, as a result of which the characteristic taste, aroma and consistency of the product are formed.

At present, raw smoked sausages are produced using molds (Penicillium candidum), applying them to the surface of the loaf. Developing mold covers the loaf of sausage with a thin layer, protecting it from excessive drying, exposure to light and oxygen, and also prevents the development of harmful bacteria and yeast. Metabolic products and mold enzymes penetrate into minced meat and contribute to the formation of a specific aroma and taste of sausage.

Boiled, liver sausages, sausages and brawns are especially perishable products. They have relatively high humidity and. in addition, they are prepared from raw materials that are usually highly contaminated with microorganisms. Although heat treatment destroys many of them, there are still a sufficient number of them.

Relatively more stable in storage are semi-smoked and especially smoked sausages, which are distinguished by a low water content, a high salt content and a significant treatment of smoke with antiseptic substances (during smoking).

Types of damage to sausages:

Souring in boiled and liver sausages is caused by fermenting carbohydrates introduced into minced meat in the form of flour and other herbal supplements, lactic acid bacteria, and the bacterium Clostridium perfringens.

The mucus of the membranes is usually due to the growth of non-spore-bearing rod-shaped bacteria and micrococci.

Molding of sausages appears during their storage at high humidity. Molds develop on the casing of sausages, and with loose stuffing, they can also be inside the loaf. Mostly smoked sausages are moldy. Potassium sorbate treatment is recommended to prevent mold development.

The rancidity of sausages is caused by the decomposition of fat by microbes. Sausages acquire a rancid taste, an unpleasant odor, and the fat turns yellow. The causative agents are most often bacteria of the genus Pseudomonas.

Pigmentation - the appearance on the shells of boiled and semi-smoked sausages of raids of various colors due to the development of pigment bacteria. On the casings of smoked sausages, coccal forms of bacteria and yeast often develop, forming a gray-white dry coating in the form of frost.

3. Microbiology of eggs. Eggs are a good nutrient substrate for microorganisms. However, the contents of the egg are protected from their penetration by the shell and shell membranes. An egg, freshly laid by a healthy bird, usually contains no or very few microbes.

The sterility of the egg can be preserved for some time, as it has a natural immunity. A significant role in immunity is played by the bactericidal substances contained in the egg (lysozyme, ovidin). During storage, the egg ages and the faster, the higher the temperature. Its immunity is reduced, and conditions are created for the penetration and reproduction of microorganisms in it. Some microbes mechanically penetrate through the pores of the shell; others, especially molds, grow through the shell.

The microflora of eggs is mainly of exogenous (after laying) origin due to contamination of the shell from the outside. However, it can also be of endogenous (lifetime) origin (in sick birds, pathogens enter the egg during its formation in the ovary and oviduct).

The bacterial flora of the egg surface is diverse. These are bacteria of the Escherichia coli group, spore bacteria, various types of pseidomonas, micrococci, mold spores. Pathogenic microorganisms, such as salmonella and staphylococci, can also be found.

Microorganisms that enter the egg usually develop near the point of penetration; their resulting accumulations (colonies) are visible during transillumination (ovoscopy (from Latin ovum - egg and Greek skopro - I look), determining the quality of eggs by translucent them with an ovoscope) in the form of spots. Some bacteria liquefy protein. They give it an unusual color (redness, greening, blackening) and an unpleasant smell (putrid, musty, cheesy). The yolk may remain unchanged; a large amount of gases (ammonia, hydrogen sulfide) can accumulate inside the egg, sometimes tearing the shell. Other bacteria cause liquefaction of the yolk, oxidative conversion of lipids, with the formation of fatty acids, aldehydes, ketones.

Often, the protein is mixed with the yolk and a homogeneous, cloudy, brownish liquid mass with an unpleasant odor is formed. With ovoscopy, such an egg is not translucent. The “sour egg” defect caused by Escherichia coli is not detected during ovoscopy, and when opened, the egg emits a pungent odor.

Molds grow primarily on the shell membrane and most rapidly near the air chamber. Then they destroy the shell membrane and penetrate into the protein.

To avoid additional contamination, eggs are recommended to be washed with disinfectant solutions before use.

Eggs are stored at a temperature of -2 0 C and a relative humidity of 85-88%. With sharp fluctuations in temperature, the shell is moistened, which contributes to the development of microorganisms.

Microflora of egg products Made from chicken eggs melange – frozen mixture of protein and yolk. The egg mixture usually contains a significant amount of various microorganisms, and during its manufacture pathogenic and opportunistic bacteria can enter. In the process of freezing and subsequent storage, the microorganisms in the melange partially die off, but a sufficient amount of them can still be preserved, especially if the melange was not immediately frozen after production.

Melange is a perishable product, it can only be stored frozen. When melange is thawed, microorganisms multiply intensively in it, so the thawed product must be sold within a few hours, keeping it chilled. To reduce the contamination of the egg mixture, it is often pasteurized for a short time (1-3 minutes) before freezing at relatively low temperatures (about 60 0 C), which do not change the physical state of the melange.

In the manufacture egg powder By drying the egg mass, not all microorganisms die. Under proper storage conditions, microorganisms cannot develop in the powder, since it has a low moisture content (3-9%), but many remain viable for a long time.

4. Microbiology of fish. Fish meat has a looser texture than the meat of warm-blooded animals, since there is less connective tissue in the muscles of fish, and this contributes to the spread of microorganisms in the body of the fish. The amount and composition of the surface microflora of freshly caught fish can vary significantly depending on the breed and type of fish, the nature of the reservoir, season, area and fishing technique. Among them, aerobic, sporeless, gram-negative rod-shaped bacteria of the genus Pseudomonas, spore-forming bacteria, and yeast predominate.

Fish caught from polluted waters may contain E. coli, salmonella and enterococci. Gills and intestines are the most contaminated with microorganisms. The causative agents of botulism are found, especially in the intestines of sturgeons. On sea fish there is a causative agent of poisoning such as toxic infections.

Fresh chilled fish- a product of short-term storage (several days) even at a temperature of about 0 0 C. At the same time, small fish deteriorate faster than large ones. On chilled fish, bacteria first multiply on the surface and gills, from where they then enter the body. In the tissues of the body of the fish, bacteria multiply less intensively.

The development of microorganisms is accompanied by significant changes in the chemical composition of fish meat. Putrefactive processes develop, as a result of which a volatile compound, trimethylamine, is formed, a substance that causes the appearance of a specific unpleasant odor that is characteristic of perishable fish.

For longer preservation, the fish is frozen or subjected to other methods of preservation: salting, smoking, pickling, drying.

Frozen fish can be stored for a long time (months) without microbial spoilage at a temperature not higher than -12-15 0 C. Covering the fish with glaze and storing at -18 0 C is a good protection. This temperature excludes the development of microorganisms.

Frozen fish may contain various micrococci, rod-shaped spore-forming and non-spore-forming bacteria, and mold spores are found in small quantities.

When defrosting, especially slow, some microbes die, but the remaining microbes begin to multiply rapidly. In this regard, the product should be thawed immediately before use.

Ambassador is one of the old ways of preserving fish. The preservative effect of salting is due to the high osmotic activity of the salt solution. Table salt inhibits cell reproduction. Predominant in salted fish are salt-resistant micrococci, spore-bearing rods, and mold spores. Therefore, various defects may appear in salted fish during storage. Some of them are due to the development of microorganisms. Red aerobic bacteria develop, causing "magenta" - red slimy plaque with an unpleasant odor. Spoilage of salted fish is caused by salt-tolerant micrococci that form a red pigment.

It is also possible to develop brown mold, which, like the magenta pathogens, gets on fish with salt. With mold damage, brown spots and stripes appear on the surface of the fish. This defect is called "rusting". Brown molds do not develop at temperatures below 5 0 C.

Slightly salted herring can be subjected to “saponification” under the influence of the development of aerobic cold- and salt-resistant bacteria. At the same time, the surface of the fish is covered with a dirty white smeared coating. The fish acquires an unpleasant taste and putrid smell. Toxigenic bacteria can also survive in salted herring: salmonella, Staphylococcus aureus, botulinum.

Lightly salted fish products from small fish (sprat, herring, anchovy), produced in hermetically sealed containers - preserves- in addition to a small amount of salt contains sugar and spices. Preserves are not subjected to heat treatment; to protect against spoilage, an antiseptic is introduced into them - sodium benzoate (0.1%). Good results instead of it or in combination with it are given by sorbic acid and the antibiotic nisin. The process of salting and ripening is carried out for 1.5-3 months. At temperatures from -5 to 2 0 C. Salt also provides some preservative effect. However, in preserves, an inhabitant of the intestines of fish from the genus Clostridium is often found. The active development of this bacterium can lead to the bombing of jars. To increase the stability of preserves in storage, it is recommended to use sterile spices.

Unlike sterilized canned fish, preserves are not long-term storage products even in the cold.

IN marinated fish the main factor inhibiting the development of bacteria, including putrefactive ones, is an acidic environment (due to the presence of acetic acid). Some preservative effect is exerted by salt, sugar added to the marinade, as well as spices containing essential oils and having phytoncidal properties. However, spices are often heavily contaminated with microbes. Molds can develop on pickled fish, which reduces the acidity of the product and creates the possibility of growth of putrefactive bacteria. Storing marinated fish in hermetically sealed containers and in the cold prevents it from molding.

Fish drying and curing- old ways of preserving it as a food product. When water is removed from fish up to a certain limit, unfavorable conditions are created for the development of microbes. Salt also has a preservative effect in dried and salted-dried fish.

With an increase in the humidity of the product and a favorable temperature, molds develop first. To prevent mold, these fish products must be stored in the cold and at a relative humidity of 70-80%.

Preservative start in smoked fish are mainly antiseptic substances of smoke (or smoking liquid). In addition to the effect of antiseptics, when hot smoking, high temperature has a detrimental effect on the microflora of fish, and when cold, the presence of salt and drying of fish. When smoked, a certain amount of microorganisms is preserved in the thickness of the fish. Bacteria of the genus Pseidomonas are very sensitive to the bactericidal substances of smoke; the most resistant are spores of bacteria and molds, as well as many micrococci.

The microflora of hot and cold smoked fish is similar to each other and is represented by up to 80% of various micrococci. There are spore-bearing and non-spore-forming rod-shaped bacteria, yeasts, and mold spores.

Hot smoked fish, compared to cold smoked fish, is richer in moisture, contains less salt, which is the reason for its faster spoilage. It is recommended to store hot-smoked fish at low temperatures (from 2 to -2 0 C) and for a short period of time.

5. Microbiology of cereals, flour, bread. Microflora of cereals. First of all, the microflora of cereals is determined by the composition of the microflora of the processed grain. The degree of contamination by microorganisms of freshly harvested grain of cereal crops, as well as grains of the same crop, can vary significantly. The environment of bacteria is dominated (up to 80-90%) by the non-spore, facultative aerobic rod-shaped bacterium herbicol.

As the grain is stored under conditions that do not allow the development of microorganisms, their number on the grain decreases due to the death of the herbicola bacterium, although it remains the predominant form. It is generally accepted that a large number of these bacteria on the grain is an indicator of its good quality. The composition of the fungal flora changes significantly. The dominant components are penicillium and aspergillus fungi (called "storage molds"), and typical representatives of freshly harvested grain, "field molds", are stored in single quantities.

Some molds found in cereals produce toxic substances. Therefore, cereals during long-term storage can be subject to various types of spoilage under the influence of microorganisms and enzymes in the cereal.

The possibility and intensity of the development of microbes are determined primarily by the moisture content of cereals, which changes during storage of products depending on the relative humidity of the air. The storage temperature also matters: the higher the moisture content of the cereal, the wider the temperature range for the possible development of microorganisms.

On cereals made from steamed grain, molds develop more intensively than on cereals from unsteamed grain. At low positive temperatures (4-5 0 C), molding of cereals is detected several months earlier.

flour microflora. The microflora of freshly ground flour, like cereals, is mainly represented by microorganisms of processed grain. The bulk consists of bacteria, among which herbicol prevails. In second place are spore-forming bacteria, the dominant of which are potato and hay sticks. Among the molds, species of the genera Penicillium and Aspergilus predominate, and mucor fungi are also found. The microflora of flour is quantitatively poorer than the microflora of processed grain. Since when it is cleaned before grinding and during the grinding process, a significant number of microorganisms are removed along with contaminants and grain shells, which are rich in microbes.

The degree of contamination of flour with microorganisms varies widely and is determined not only by the degree of contamination of the processed grain, but also by the nature of its preparation for grinding, cleaning method, grinding method, flour yield and its grade.

The lower the grade of flour, the more peripheral grain particles get into it, the more microorganisms it contains. The number of mold spores in flour of all varieties (the lower the grade, the more) exceeds their content in processed grain. The grinding products passing through the machines are contaminated with mold spores as a result of the contact of flour particles with the separating grain shells, with production equipment, with the air flow used in the production process.

Flour is a product less resistant to microbial spoilage than grains and cereals, the nutrients in it are more accessible to microorganisms. However, their development under the correct storage regime (at a relative air humidity of not more than 70%) is prevented by a low moisture content in the flour; there is even a gradual death of vegetative cells of bacteria.

With an increase in the relative humidity of the air, the microorganisms that were in the flour in an inactive state begin to develop, and molds develop first of all, since they are able to grow at a lower moisture content than bacteria. Baking properties of flour during their development are reduced. They acquire an unpleasant musty smell, which is usually transferred to bread.

molding flour- the most common type of damage to it. Moldy flour is not safe: Aspergillus and penicillium are found on it, capable of producing mycotoxins, many of which are heat-resistant and can persist in bread.