The modern food industry is no longer conceivable without processessterilization and pasteurization. Not only large production facilities, but also absolutely all catering establishments, especially fast food, are interested in the possibility of long-term storage of products without loss of quality.

Technologies for suppressing the vital activity of microorganisms are most in demand in canning. They are designed to provide nutritional value and preserve finished products in glass, tin and PET containers from spoilage. In order for the processing process to be as effective as possible, it is necessary to choose the right sterilization method.

In many respects, one or another principle of sterilization depends on the pH of the product and the specificity of the microorganisms affecting it. Naturally, the microflora of liquids, vegetables, meat or fish differs from each other. Thus, acidic products (juices, compotes, etc.) are processed at a temperature of no more than 100 ° C at atmospheric pressure (pasteurization). Canned vegetables and meats require exposure to higher temperatures and often excess pressure. This is necessary so that the specified temperature penetrates all layers of the product.

Today in the food industry they use three main type of sterilization: thermal, microwave (electromagnetic) and hydrostatic.

Thermal processing method- The most common. The duration of sterilization, as mentioned above, depends on the type, thickness and size of the container, as well as the consistency, thermal conductivity of the product and other factors. Installations for this type of sterilization are called autoclaves (baths).

For pasteurization (not higher than 100 °C), open batch devices are used. They are equipped with bubblers for steam supply. In other cases, sealed continuous sterilizers are used. They provide a temperature of 110-125 °C and sterilize with saturated steam or hot water under pressure above atmospheric pressure.

Microwave sterilization- this is the near future in the rapid processing of finished products. The traditional thermal method has a number of disadvantages. The main one is the disinfection of food before the packaging process, which makes it possible for the product to become recontaminated during packaging.

The use of electromagnetic microwaves in the microwave range makes it possible to achieve complete sterilization inside the package due to uniform heating of absolutely all areas. Moreover, no preservatives are required, and the shelf life is at least 9-12 months. Now microwave sterilization lines operate everywhere. The leader is the United States, but other countries are also increasingly introducing this technology, including Russia.

Sterilization using high hydrostatic pressure- a unique, but still very expensive method of sterilizing food products. It has long been used in America, but is little popular in Europe. To work using this technology, you need to build a real workshop. In a special steel cylinder, a powerful piston compresses the water, creating a pressure of 4,000 to 6,000 bar.

This type of processing allows sterilization both in packaging and without it. For example, fresh fish can be stored for up to 80 days. However, not all products can be processed in this way. Only those that do not have air cavities. Despite the excellent productivity of such installations (up to 50 tons/day), there is a factor that greatly hinders their widespread implementation - the cost of several million euros. However, according to experts, in just a few years this technology may become one of the leading ones.

Both domestic and foreign companies are successfully engaged in the development and production of pasteurization and sterilization plants. Therefore, the choice must be made based on the required functionality and, of course, the cost of the device. Below we bring to your attention a description of a number of popular models of sterilization equipment.

Horizontal closed sterilizer AG-1200 from UralTsentrKomplekt (Russia)

This is an installation using thermal technology. The sterilizing effect is calculated online, which makes it possible to adjust the temperature in real time. The device is equipped with a powerful water distribution system that circulates water at a speed of up to 120 m³/hour. This ensures a high heat transfer coefficient in a short period of time, which, in turn, allows for significant energy savings. Finally, the AG-1200 sterilizer is capable of sterilizing food products in any packaging (glass containers, cans, lamister (steralkon), retort bags, etc.).

Flow pasteurizers for food liquids “H&G” from “HERMIS” (Lithuania)

Designed for continuous heat treatment of juices, beer, kvass, wine and other drinks. Capacity from 2000 to 30000 l/hour. It is very effective thanks to its unique electronic filling: temperature sensors, debitometers, conductometers, electro-pneumatic valves, etc.

Sterilizer ED 23 from Binder (Germany)

A device operating using microwave technology with the possibility of sterilization at temperatures up to 300 °C. Features APT.line™ preheating as well as digital temperature control with degree accuracy. Thanks to memory, it is able to reproduce previously set sterilization parameters. It can work up to 100 hours non-stop, and, in case of a problem, automatically switches off.

In the general meaning of the word, sterilization refers to the processing of products in which all microorganisms and their spores are completely destroyed. Sterilization of the product can be ensured:

• heating it to a high temperature;
• treatment with ionizing radiation;
• introduction of chemicals that cause the death of microorganisms;
• other methods or a combination of several methods, for example, the introduction of chemicals followed by heating to high temperatures.

In industrial conditions, complete sterilization of food products is not achieved; this requires significant sterilization. It is enough that the product does not contain pathogenic microorganisms and that it is shelf stable.

Therefore, in the practice of food preservation, they are sterilized to industrial sterility (and not to complete sterility, as is customary, for example, in medicine when sterilizing instruments). After sterilization, a certain amount of spores and even vegetative forms of microorganisms remain viable in the product.

The number of surviving microorganisms (spores) depends on the degree of sterilization, which in turn depends on the purpose of the canned food, or, more precisely, on the intended storage conditions.

In foreign practice, depending on the degree of completeness of sterilization, three main types of canned food are distinguished (sometimes a wider gradation is used):

• tropical;
• full canned food;
• preserves (semi-canned).

Tropical canned food is sterilized until all viable vegetative forms of microorganisms and their spores are completely suppressed, including mesophilic, that is, heat-loving bacteria and their spores.

Tropical canned food can be stored at high temperatures - 30-40UC, that is, in the optimal temperature range for the development of most putrefactive microflora.

Full canned food, or simply canned food, is sterilized until all vegetative forms of microorganisms and most of their spores are suppressed.

However, a small number of spores of mesophilic bacteria remain, although greatly weakened, but viable, and when exposed to favorable conditions (that is, under unfavorable storage conditions for canned food), for example, during storage of canned food at elevated temperatures (30-35 ° C), they can multiply, thereby causing spoilage of canned food. Therefore, it is not recommended to store canned food at temperatures above 25°C.

Preserves are sterilized until most vegetative forms of microorganisms are suppressed. A small number of vegetative forms of mesophilic microorganisms and most of the spores remain viable and easily develop at room temperature. Therefore, preserves are stored at low positive or high negative temperatures, in most cases at a temperature of about 0°C.

The domestic industry mainly produces whole, or simply canned, and preserved foods. In small quantities, on special orders, canned food is produced for hot climates, similar in microbiological parameters to tropical canned food.

The most widespread in industry is the sterilization of products by exposure to high temperatures. Naturally, after sterilization, the product should not come into contact with air or any other environment containing microorganisms, so that the so-called secondary, or repeated, contamination does not occur. Therefore, sterilized products, called “canned food,” must be packaged in hermetically sealed containers.

Thus, canned food includes food products packaged in metal, glass, plastic, laminated or combination of these materials containers, which after filling these containers or before by heat treatment have become stable during storage.

Canned food also includes preserves, which differ from canned food itself in being less stable during storage.

Drying meat and fish products
When heat-drying meat, its properties change greatly, so this processing method is not used on an industrial scale, with the exception of drying sausages and meat components in the manufacture of food concentrates.

The influence of the drying process on the properties of products
An increase in the temperature of the product during the period of falling drying affects its properties to a much lesser extent than during thermal drying, since the thermal stability of protein substances with a decrease in moisture in them increases significantly. Under optimal drying conditions, the product temperature is increased when the moisture content in the dried layer is reduced to 15% or less.

Sublimation temperature
The sublimation temperature (that is, the drying temperature) is determined depending on the amount of frozen water. After reaching the cryoscopic temperature, water in the product begins to freeze or crystallize, as a result of which the concentration of the remaining liquid phase increases and its cryoscopic temperature decreases. With a further decrease in temperature, the amount of frozen water increases, but part of it remains in a liquid state until the cryohydrate temperature is reached. Products of animal origin and fish contain a small amount of calcium chloride, the cryohydrate point of an aqueous solution of which is -55°C, so complete freezing of water in such products is possible at temperatures below this.

Freeze drying
Freeze drying of food products under high vacuum conditions is becoming increasingly popular. Freeze drying becomes intense only in deep vacuum conditions with a significant heat input.

Drying with infrared rays
For drying plant food materials, short-wave infrared rays (SWIR) with a wavelength of about 1.6-2.2 microns have been used in practice. When drying ICL, a heat flow is supplied to the material several tens (30 to 70) times more powerful than during convective drying.

Contact method
The contact drying method is based on the transfer of heat to the material upon contact with a hot surface. In this method, air serves only to remove water vapor from the dryer, being a desiccant. The temperature in different layers of the material is different: the highest is in the layer in contact with the heating surface, the lowest is in the outer layer. The moisture content during contact drying gradually increases from the layers in contact with the heated surface to the outer layers. Thus, the speed of contact drying is determined only by the temperature gradient; the moisture content gradient has an inhibitory effect on the movement of moisture to the surface of the material.

Drying liquid materials in a spray state
Spray dryers are widely used in the dairy industry for drying milk, dairy baby food products, as well as for drying egg mass and other products. In these installations, a large surface area is created for the evaporation of fine particles of the solution, which are dehydrated in a stream of hot air (the surface area of ​​1 kg of solution as a result of spraying increases several thousand times, reaching 600 m2).

Flash drying
Wet particles of coarse-grained material move into the fluidized bed at a higher critical air speed and lower bed resistance than dry particles. This is explained by the large adhesion forces of wet particles, which leads to the formation of aggregates and numerous channels between them.

Convective method of drying food
Lump and grain materials are dried using this method. Heated air, flue gases or superheated steam are used as a drying agent. The drying agent transfers heat to the material, under the influence of which moisture is removed from the material in the form of steam and released into the environment. Thus, the drying agent during convective drying is a coolant and desiccant.

Methods for drying food
Liquid food products can be dried using fine spray systems. The resulting dry product after watering is quite comparable in taste and technological properties to the native product.

Effect of drying on product properties
To remove moisture during drying, heat must be supplied to the product, the effect of which on the product is discussed in the section “Thermal processing of food products”. When drying, the mechanism of heat action on the product is the same as during heat treatment. However, the product is heated to a lower temperature, so the loss of nutrients is usually small.

Moisture transfer process
The chemical composition of food products, and for meat and fish, the technological properties of muscle tissue, have a noticeable effect on moisture transfer during drying.

Drying as a method of food preservation
Chemically bound, or hydration, water is most tightly bound to the material by chemical bonds and has the maximum energy of binding with the material. Since hydration water is chemically bound, it loses its normal properties, that is, it does not dissolve chemicals, has a lower freezing point and a higher boiling point.

Dehydration of food
Food preservation by drying is based on the principle of suspended animation. It is known that the nutrition of microorganisms occurs by osmosis, the absorption of nutrients, therefore, for their development, the product must contain a certain amount of water. The development of bacteria is possible at a moisture content of 25-30% or more, mold fungi - 10-15% or more.

Aseptic food preservation
The temperature of the superheated steam is maintained automatically, and the holding time of the cans in the sterilizer is regulated by the speed of the cable conveyor. The lids are sterilized using superheated steam in a special device built into the lid magazine of the seaming machine. Sterilization of the seaming head is carried out at 127°C for 20-30 minutes.

Technique for heat sterilization of canned food
For sterilization of canned food, periodic and continuous devices are used. Depending on the temperature at which sterilization is carried out, what pressure is created in the jar and what kind of canning container is used, canned food is sterilized in open autoclaves at atmospheric pressure, but mainly in closed apparatus using excess pressure.

Sterilization of fruits and vegetables
Depending on the reaction of the environment (pH value), fruit and vegetable products are classified into one of the following groups. Canned food of group A is classified as slightly acidic, so the sterilization regime must ensure the death of botulism pathogen spores in them. In canned vegetables of this group (green peas, green beans, sweet corn, pureed canned foods for baby and diet food, and others), souring is sometimes observed without the formation of bombage.

Sterilization (pasteurization) of milk
Depending on the canning methods used, canned milk is divided into condensed and dry. Condensed ones, in turn, are divided into canned ones by sterilization and increasing osmotic pressure by adding sugar.

Changes in the taste of food during canning
Sterilization of canned meat, especially in conventional stationary autoclaves, on the contrary, causes a significant change in the taste of the product. In terms of aroma, taste, tenderness, and juiciness, canned meat differs significantly from conventionally cooked or pasteurized meat. The structure of the meat becomes fibrous, pieces of it fall apart when chewed, so the concept of “tenderness” has little application to canned meat. Such meat is assessed as unsucculent and dry, which is especially typical for canned poultry meat.

Sterilization of meat and fish products
Meat and fish products are low-acid (according to the domestic classification they are classified as group A). The sterilization regime used for them is designed, with some exceptions, to destroy microorganisms, except for most thermophiles and, possibly, some types of aerobic spore-forming mesophiles. Exceptions include canned or marinated meat products containing preservative salts, which, by virtue of their action, allow use a less stringent regime than is necessary for meat products without preservatives.

Sterilization of food products – This is a treatment of the product that ensures the complete death of all microorganisms and their spores.
Sterilization of the product can be ensured:
- heating it to a high temperature;
- treatment with ionizing radiation;
- other methods or a combination of several methods, for example the introduction of chemicals followed by heating to high temperatures.
Canned food, in accordance with microbiological quality indicators, is divided into sterile and industrially sterile.
Canned food in sealed containers, produced using technology that ensures that the product is free of microbial toxins, microorganisms hazardous to consumer health, and microorganisms that can cause spoilage of the product, and that meet these requirements are classified as industrially sterile.
The industry produces canned food that meets the requirements of industrial sterility.
Sterilization of canned products is the main and final process of canned food production - this is heat treatment of the product, ensuring the complete destruction of non-heat-resistant, non-spore-forming microflora and reducing the number of spore-forming microorganisms to a certain specified level, sufficient to prevent microbiological spoilage of the product when stored at a temperature not exceeding 25 o C and guaranteeing microbiological indicators of the safety of eating canned food.
Achieving these goals should be carried out under the condition of maximum preservation of the organoleptic properties and nutritional value of finished canned food, their tightness and normal appearance.
At the same time, sterilization of canned products is the most labor-intensive and energy-intensive process in the production of canned food.
In countries with a fairly developed canning industry, including the Russian Federation, great attention is paid to the technology of production of canned products and, first of all, to their sterilization. This is determined by the fact that violations in sterilization can cause increased defects in canned food and cause food poisoning. In the Russian Federation, as in other countries, scientifically based instructions and rules have been introduced and are in force, mandatory both for the staff of canning enterprises and for employees of research organizations, primarily strictly regulating the sterilization process.
Currently, in the field of production of canned products in the Russian Federation, the following regulatory documents are in force: “Instructions on the procedure for sanitary and technical control of canned food at manufacturing enterprises, wholesale warehouses, retail trade and public catering establishments”, approved by the Ministry of Health of the Russian Federation, “Product Safety System nutrition based on the principles of HASSP”, Moscow 2004, as well as “Guidelines for the development of sterilization and pasteurization regimes for canned products” developed and approved. 2011 GNU VNIIKOP.
The rules are periodically reviewed and refined in accordance with the results of scientific research, industry objectives and the requirements of health authorities.

The main way to preserve a food product without significant changes in its taste is sterilization.

The method of sterilizing canned food in glass containers with immediate sealing with tin lids after boiling is very convenient at home. It provides the necessary tightness and vacuum in the pumped jar, reaching 300-350 mm Hg, and contributes to the preservation of the canned product and its natural color.

Sterilization of canned food at home is carried out at the boiling point of water.

Fruit compotes and vegetable marinades can be sterilized at a water temperature of 85 degrees (pasteurization). But in this case, pasteurized canned food should be in the sterilizer 2-3 times longer than in boiling water. A thermometer is used to determine the water temperature.

In some cases (for example, for sterilizing green peas), when the boiling point of water during sterilization should be above 100 degrees, table salt is added to the water. In this case, they are guided by the following table:

Canned food prepared at home is sterilized in a pan, bucket or in a special sterilizer. A wooden or metal grid is placed horizontally on the bottom of the dish. It eliminates the breakage of cans or cylinders during sterilization under sudden temperature fluctuations. You should not place rags or paper on the bottom of the sterilizer, as this makes it difficult to observe the beginning of the water boiling and leads to defective products due to insufficient heating.

So much water is poured into the pan to cover the shoulders of the jars, that is, 1.5-2.0 cm below the top of their necks.

The temperature of the water in the pan before loading filled cans should be at least 30 and no more than 70 degrees and depends on the temperature of the loaded canned goods: the higher it is, the higher the initial temperature of the water in the sterilizer. The pan with the jars placed in it is placed on intense heat, covered with a lid and brought to a boil, which should not be violent during sterilization.

The time for sterilization of canned food is counted from the moment the water boils.

Rice. 20. Pan adapted for sterilization

The heat source at the first stage of sterilization, that is, when heating the water and the contents of the jars, must be intense, since this reduces the heat treatment time of the product, and it turns out to be of high quality. If we neglect the speed of the first stage, then the canned food produced will be overcooked and will have an unsightly appearance. The time for heating water in a pan to a boil is set: for cans with a capacity of 0.5 and 1.0 liters - no more than 15 minutes, and for 3-liter cylinders - no more than 20 minutes.

At the second stage, that is, during the sterilization process itself, the heat source should be weak and only maintain the boiling point of water. The time specified for the second stage of sterilization must be strictly adhered to for all types of canned food.

The duration of the sterilization process depends mainly on the acidity, thickness or liquid state of the product mass. Liquid products are sterilized within 10-15 minutes, thick ones - up to two or more hours, acidic products - less time than non-acidic ones, since an acidic environment is not conducive to the development of bacteria. The time required for sterilization also depends on the volume of the container. The more, the longer the boiling lasts.

Is the lid sealed well and does it not turn around the neck of the jar?

Rice. 21. Metal grill

Rsi. 22. Sterilization of canned food in a pan

There are special tongs available for removing hot jars from pans. They are very convenient to use.

Sealed jars or cylinders are placed neck down on a dry towel or paper, separating them from one another, and left in this position until cooled.

Steam sterilization of jars

Canned food is sterilized with steam in the same container where water is boiled for this purpose. The amount of water in the pan should not exceed the height of the wooden or metal grate - 1.5-2 cm, since the less water, the faster it heats up.

When the water boils, the resulting steam warms the jars and the contents in them. To prevent steam from escaping, the sterilizer is tightly covered with a lid.

The time required to bring the water in the sterilizer to a boil is 10-12 minutes.

The time required to sterilize canned food with steam is almost twice as long as when sterilizing in boiling water.

Pasteurization of canned food in jars

In cases where it is necessary to sterilize canned food at a temperature below boiling water (for example, for marinades, compotes), they are cooked at a water temperature in the pan of 85-90 degrees. This method is called pasteurization.

When cooking canned food using the pasteurization method, you must:

1. use only fresh, sorted fruits or berries, thoroughly washed from dust;
2. strictly adhere to the temperature and time of pasteurization;
3. Before laying the container, wash it thoroughly and boil it.

To measure the temperature of the water in the pan during pasteurization, use a thermometer with a scale of up to 150 degrees.

The preservation of canned food prepared by pasteurization is facilitated by the presence of high acidity. You can pasteurize cherries, sour apples, unripe apricots and other acidic fruits for preparations and compotes.

Repeated sterilization. Repeated or multiple (two to three times) sterilization of the same jar of food products containing large quantities of protein (meat, poultry and fish) is carried out at the boiling point of water.

The first sterilization kills mold, yeast and microbes. During the 24-hour period after the first sterilization, the spore forms of microorganisms remaining in the canned food germinate into vegetative forms and are destroyed during secondary sterilization. In some cases, canned food, for example meat and fish, is sterilized a third time a day later.

To re-sterilize at home, you must first seal the jars and put special clips or clips on the lids so that the lids do not come off the jars during sterilization. The clamps or clips are not removed until the cans have completely cooled (after sterilization) to avoid the lids falling off and possible burns.

Salt must be of food quality, clean, without foreign impurities. It is best to take premium or first grade salt. Brine prepared from first grade salt must be filtered to remove insoluble foreign impurities.

Water. To prepare canned food, use only fresh and clean water. It should be soft and not give sediment after boiling. Before drinking, hard water should be boiled, cooled and filtered to remove sediment.

Spices, used for the preparation of canned food, are the following: bitter and allspice peppers in grains and ground, red and green bitter capsicums, bay leaves, cinnamon, cloves and others.

In addition, they use fresh spicy herbs: dill, parsley, horseradish leaves, celery, caraway seeds, etc.

When preparing this or that amount of filling, marinade, syrup, you can use an approximate table of the weight of some products (in g):

Product	Tea spoon	Tables, spoon	Faceted glass	Thin-walled glass	0.5 l jar	1.0 L can
Water		15—20	200	250	500	1000
Granulated sugar	10—12	20—25	200	250	420	800
Salt	8—10	25--30	260	325	650	1300
Vinegar	5	15—20	200	250	500	1000
Vegetable oil	5	20	200	240	480	960

Note. The mass (weight) of bulk products is indicated flush with the edge of the spoon, without a slide.

Probably, few consumers of imported meat, poultry, and pharmaceutical products have asked themselves the question of how these products are processed and sterilized. And if the term “sterilization” in the food sense of the word is associated primarily with milk, dairy products or, for example, bandages, syringes, then few people have any idea about sterilization using gamma radiation, electron beam radiation or ethylene oxide. But many food products, especially meat and chicken, are sterilized using these methods. The specificity of these technologies is that the product is processed already in packaging, and not only in primary packaging, which is in direct contact with the surface of the product, but more often in secondary packaging, i.e. when the product is fully packaged and ready for shipment. At this stage, electronic and ethylene oxide sterilization technologies come into play.

The gas is ethylene oxide (EO), particularly effective for processing unit doses of drugs enclosed in sealed containers, products that become discolored, deformed, or otherwise altered when processed by radiation sterilization methods. The EO process involves first placing the product in a high-humidity environment for a certain period of time. Moisturizing the product is necessary to make the sterilizing agent more effective. After this, the product is placed in a chamber for several hours, where it is sterilized with ethylene oxide. Next, in order to remove residual gases from the product, it is placed in another chamber; gases dissipate in it. The last stage of the process takes several days. And even after the complete completion of the sterilization cycle, the product remains in the laboratory for another 3-7 days until the sterility test confirms the complete destruction and destruction of microbes. Each portion of products subjected to EO is supplied with special biologically active indicators - “spore” strips, which determine the quantitative content of microbes. There is another specific feature of the process: the product must be enclosed in air-permeable packaging so that gases can freely escape from the product after it has been subjected to EO treatment. This type of packaging exists, but it is very expensive. The entire process of EO sterilization requires strict control of a number of parameters for each loaded portion of products: period of exposure to EO gas, humidity, temperature, pressure, EO concentration, vacuum. If even one of the parameters is out of control, the effectiveness of the entire process may be called into question. The widespread use of this method is hampered by its potential danger: ethylene oxide is believed to have carcinogenic properties. Recently, close attention of the “greens” has focused on the process of removing waste gas into the environment. The method was also affected by strict restrictions from government legislation, as a result of which the cost of the process sharply increased and unprofitably increased the final cost of sterilized goods.

Another method of sterilization - gamma radiation - is applied to products already in their final packaging, ready for shipment. The source of radiation is the radioactive isotope cobalt-60, less commonly cesium. The radioactive isotope is enclosed in a kind of pencil case - a “pencil” - then, already at the plant, the “pencils” are placed on special shelves and, in such “uniform”, are brought into the gamma cells. The product, packaged in the final shipping container, passes on a conveyor through a gamma cell, where it is sterilized for 4-8 hours. Over time, cobalt 60 tends to decay and its emission weakens. To constantly control the amount of radioactive isotope, it is necessary to tightly regulate the time of each cycle. The radiation dose received by a product is a function of the duration (time) of exposure to the radioactive source. The most commonly used doses for sterilization are in the range of 25 to 35 kGy. However, some products require a lower or higher dose of radiation to kill pathogenic microbes. To sterilize them, you have to wait until the timer setting is changed. It is not easy to adjust gamma equipment to increase or decrease the dose range, so often if a product requires sterilization at a dose significantly less than 25 kGy, it must be irradiated at that maximum dose. As the radioactive source is “depleted”, it is replaced with a new one. This takes several days, during which the gamma cell remains inoperable. Due to the duration of exposure to this type of sterilization, product degradation in the form of discoloration (including packaging) and/or embrittlement is possible, which limits the use of this method. Despite the obvious inconveniences associated with gamma radiation, this method remains the most widely used. Dozens of packaging materials are adapted to gamma radiation (meaning materials in direct contact with the product). Among them are polyethylene and all its varieties, polyvinyl chloride, polyvinylidene chloride, nylon-6, ethyl vinyl acetate. Bulk products packaged in bulk or loose, such as spices, spices, dried fruits, etc., are also exposed to gamma radiation.

In recent years, a new safe sterilization technology has emerged - electron beam. Unlike gamma ray and ethylene oxide sterilization methods, electron irradiation does not use radioactive isotopes.

The commercial application of electron beam technology has been limited by two factors: cost and the lack of scientifically proven packaging options. George Sadler, professor at the National Center for Food Safety Technology, Illinois, notes: “Cathode beam systems have been around since the 1950s, but until recently they were very expensive to operate. Only one company, Cryovac, has been able to obtain approval from the US Food and Drug Administration (FDA) to use a single packaging material for EL processing of packaged foods - ethylene vinyl acetate beam method uses high levels of electron energy as a means of sterilization. Electrons are accelerated to the speed of light using a linear accelerator. The total energy, consisting of an energy range from 3 to 10 million electron volts (eV), combined with electricity in the range from 1 to 50 kW, is sufficient to penetrate the product, packaged in containers ready for shipment. Electrons, scanning the product, pass through many secondary particles, including ions and free radicals. Secondary particles break the DNA chains of microorganisms both on the inner surface of the package and inside the product, thus blocking their further reproduction. Pathogenic microbes are destroyed and the product is sterilized.

Note that electron beam (EB) radiation does not imply deep penetration into the thickness of the product, as gamma radiation does. EL penetrates the product to a depth of 7.5 cm from the surface. The effect of EL radiation is limited to a few seconds, in contrast to many hours of exposure to gamma radiation on the product. The short duration of exposure to accelerated electrons reduces the possible effects of product oxidation, minimizing disturbances in the structure of both the product and the packaging material. Most importantly, EL- (EVA). Most other packaging films were approved and tested in the 1960s for gamma radiation only. With time and advanced technology development, the cost of EL sterilization has dropped to a very reasonable level, attracting interest from the food and packaging industries. Now is the time to expand the range of packaging options for EL sterilization.”

Professor Sadler is leading a working group of 20 companies, mostly large plastics suppliers and processors such as DuPont, Dow, Cryovac, American National Can, seeking FDA approval for an expanded range of packaging films and some semi-rigid and hard plastics. The group tested and developed documentation for the use of materials such as ethyl vinyl alcohol (EVON), nylons, and all ionomers. “The interest in EL radiation is dictated primarily by safety considerations of this sterilization method. We predict that fresh and processed meat and chicken will be the first applications of this technology. Several questions remain unresolved, particularly regarding composite laminate packaging materials and how they will be affected by electron beam radiation. It is expected that about 80-90% of single-use medical plastic packaging will be compatible with EL processing,” says George Sadler.

Major meat processors such as IBP, Tyson Foods, Cargill, and Emmpak have announced plans to conduct joint research with Titan Corporation, the sole owner of SureBeam's suite of EB-radiation equipment and a patented technology called electronic cold pasteurization technology. Meat and chicken processing companies suggest that cold pasteurization can extend the shelf life of frozen meat products.

Experts are inclined to believe that “if gamma radiation was the first step towards the use of this kind of technology, EL radiation was the second, then the time will soon come to use x-rays as a radiation source. The latest technology combines the speed of the electron beam method and the deep penetration of gamma radiation."

Marina MONAKHOVA

PakkoGraff Browser

Topic of the article: radiation sterilization, ethylene oxide sterilization