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 effects. 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 - 30-40 ° C, 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.

Sterilization.

Sterilization is heating a product to a temperature above 100°C to suppress the vital activity of microorganisms or to completely destroy them.

The main sources of contamination of canned food before sterilization are raw meat, auxiliary materials and spices. Contamination occurs during deboning, trimming, from tools, from the hands of workers, air, containers, etc.

Before sterilization, bacterial contamination is checked in order to clarify the sterilization regimes and storage conditions of the product. The total amount of o/o in 1 g should not exceed:

Stewed meat – 200,000 microbial cells;

Meat pate – 10,000 microbial cells.

Before sterilization, canned food may contain toxigenic spore-forming anaerobes Cl. botulinum and putrefactive anaerobes Cl. sporogenes, Cl. perfringens, Cl. Putrificum, thermophilic microorganisms Bacillus coagulans, etc.

Heating meat at a temperature of 134? C for 5 minutes destroys almost all types of spores. However, exposure to elevated temperatures leads to irreversible, profound chemical changes in the product. In this regard, the most common and maximum permissible temperature for sterilization of meat products is within 120°C. In this case, a heating duration is selected that ensures sufficiently effective neutralization of spore forms of microbes and a sharp decrease in their vital activity (? 40 min).

The sterilization regime is determined by the temperature and duration of its exposure. The correct sterilization regime guarantees a high quality product that meets the requirements of industrial sterility (if 1 g of product contains no more than 11 B. subtilis cells in the absence of botulism and other toxigenic forms).

Concept of sterilization formula.

The jars are loaded into periodic or continuous apparatuses, the installation and jars are heated to the sterilization temperature, sterilization is carried out during the period of death of microorganisms, after the temperature of the apparatus decreases, the jars are unloaded, and the cycle is repeated. The conventional recording of the thermal regime of the apparatus in which canned food is sterilized is called the sterilization formula. For periodic devices, this entry has the form
(A+B+C)/T

where A is the duration of heating of the autoclave from the initial temperature to the sterilization temperature, min; B - duration of sterilization itself, min; C - duration of temperature reduction to a level allowing unloading of the apparatus, min; T-set sterilization temperature, °C.

The temperature in the central zone of the jar lags behind the temperature in the autoclave, which is explained by the low thermal conductivity of the product. The rate of heating of the contents of the jar, in turn, depends on the type of heat transfer: in the liquid component of canned food, heat transfer occurs faster; In the dense part of canned food, heat transfer occurs more slowly.

When determining sterilization modes, you need to know:

1) the temperature of the contents of canned food changes over time during the heating process, and the canned food is heated unevenly by volume;

2) the liquid part of canned food warms up faster than the dense part;

3) the most difficult point to warm up is the one located slightly above the geometric center of the can, since heat transfer from the lid side is inhibited (in non-vacuum canned food) due to the presence of an air bubble in the empty space of the can;

4) the temperature in the central zone of canned food changes over time differently than in the apparatus itself (autoclave).

Thus, the value of the values ​​of A, B, C and T in the sterilization formula characterizes only the operating mode of the device and does not reflect the degree of effectiveness of the heat treatment parameters on the canned product.

Considering the values ​​included in the sterilization formula, one can notice that the T value is chosen as the maximum permissible temperature for a given type of canned food (i.e., causing the smallest changes in the quality indicators of the product), and the values ​​of A and C depend mainly on the design features of the autoclave. The higher the initial temperature of the contents of the jar, the less time A is required to warm it up to the required temperature level.

The value of value A will depend only on the volume and type of container. In this regard, when working on vertical autoclaves, constant set values ​​of A are used: for tin cans with a capacity of up to 1 kg - 20 min, for cans with a larger capacity - 30 min, for glass jars with a capacity of 0.5 kg - 25 min, with a capacity of 1 kg - 30 min.

The value of C is due to the need to equalize the pressure in the sterilized jar with atmospheric pressure before unloading the autoclave. Neglecting the pressure reduction step leads to irreversible deformation of cans or to the breaking of lids from glass containers.

Heating of the product during the sterilization process (stages A and B) is accompanied by an increase in internal pressure inside the jar. The amount of excess internal pressure in the sealed volume of the can depends on the moisture content, the degree of vacuum, the degree of expansion of the product as a result of heating, as well as on the filling factor of the can and the degree of increase in the volume of the container due to thermal expansion of the material and swelling of the ends of the cans.

The degree of thermal expansion of the container material (especially glass) is always lower than the degree of thermal expansion of meat products. Therefore, regulated values ​​for the filling factors of cans are established: for tin cans - 0.85-0.95, for glass cans - less.

The excess pressure in the jar compared to the pressure in the autoclave is mainly due to the pressure of the air present. Evacuation of cans, as well as heating the contents of canned food before capping, can reduce the amount of internal pressure. The level of pressure difference in the jar and in the sterilizing apparatus should not exceed certain limits. With a can diameter of 72.8 mm, the value of Pcr is 138 kN/m2, with a diameter of 153.1 mm, respectively, 39 kN/m2.

To create these conditions, compressed air or water is supplied to the autoclave during sterilization. It is better to create back pressure with water, which has a high thermal conductivity coefficient and at the same time serves as a heating medium.

The reduction in pressure in the apparatus to atmospheric pressure at the end of sterilization, which is necessary to unload the autoclave, leads to an increase in the pressure difference in the jar and the autoclave, since the canned food remains at a high temperature. For this reason, the pressure is equalized gradually by supplying cold water to the autoclave at a pressure equal to that established in it at the end of sterilization. As a result of the rapid cooling of canned food, the internal pressure drops, which allows you to carefully lower the pressure in the autoclave itself. The final cooling temperature for cans before they are unloaded from the autoclave is set to 40-45°C.

The period of time required to reduce the pressure in the apparatus (value C) averages 20-40 minutes.

Sterilization does not always achieve complete death of microorganisms. It depends on the:

1. The more heat-resistant the microorganism, the more difficult it is to cope (spores of Bacillus subtilis can withstand 130? C).

2.Total number of microorganisms.

3. From the consistency and homogeneity of the product (in liquid canned food, the o/o perishes in 25 minutes, and in dense canned food - in 50 minutes).

5. from the presence of fat (E. coli in broth at 100? C dies in 1 second, and in fat - in 30 seconds.

6. from the presence of salt and sugar.

Sterilization in an electromagnetic field by high-frequency (HF) and ultra-high-frequency currents. Sterilization is achieved due to the generation of heat in the cells of microorganisms under the influence of an alternating electromagnetic field. Sterile meat can be obtained by heating to 145°C for 3 minutes. At the same time, HDTV and microwave heating ensure the preservation of the nutritional value of the product.

Sterilization by ionizing radiation. Ionizing radiation includes cathode rays - a flow of fast electrons, X-rays and gamma rays. Ionizing radiation has a high bactericidal effect and is capable of providing complete sterilization without causing heating of the product.

The duration of sterilization by ionizing radiation is several tens of seconds. However, high irradiation intensity leads to changes in the constituent parts of meat. After ionization treatment, the product inside the jar remains raw, so it must be brought to a state of culinary readiness using one of the usual heating methods.

Hot air sterilization. Hot air at a temperature of 120°C circulates in the sterilizer at a speed of 8 - 10 m/s. This method makes it possible to increase heat transfer from the heating medium to canned food and reduce the likelihood of overheating of the surface layers of the product.

Sterilization in batch devices. The most common types of periodic apparatus for sterilizing canned food are autoclaves CP, AB and B6-ISA. Autoclaves are divided into vertical (for sterilizing canned food produced in tin and glass containers, with steam or in water) and horizontal (for sterilizing canned food in tin containers with steam). Temperature and pressure in autoclaves are controlled manually or using pneumatic and electrical software devices - thermostats.

Cans are placed in autoclave baskets manually, by loading them in bulk with a conveyor (with or without a water bath), hydraulic and hydromagnetic stackers. Unloading is carried out by overturning the autoclave baskets.

Rice. 1. Hydrostatic sterilizer A9-FSA:

1 - heating chamber; 2 sterilization chamber; 3 - primary cooling chamber; 4 - additional cooling chamber; 5 - cooling pool; 6 - loading and unloading mechanism; 7 - line for draining water into the sewer; 8 - chain conveyor

Sterilization in continuous devices. Continuous sterilizers are divided into rotary, horizontal conveyor, and hydrostatic. The first two types are rarely used.

Continuous hydrostatic sterilizers use the principle of balancing pressure in the sterilization chamber using hydraulic sluices.

In hydrostatic sterilizers, the length of the conveyor sections in the heating and cooling zones is the same, so the sterilization formula has a symmetrical form A-B-A. The sterilization temperature is maintained by adjusting the position of the water level in the sterilization chamber.

A hydrostatic sterilizer works as follows. Cans are loaded into can carriers of an endless chain conveyor, which delivers them into the shaft of a hydrostatic (water) gateway. After heating, the cans enter the steam sterilizer chamber, are heated to 120 °C and enter the water cooling zone, where the temperature of the canned food drops to 75-80 °C. After leaving the hydrostatic seal, the cans enter an additional water cooling chamber (40-50°C), after which the canned food is unloaded from the sterilizer.

When using continuous sterilizers, there is no need to preheat the device, therefore two values ​​of the sterilization formula A and B form one B' and it takes the form (B" + C)/T.
Pasteurization.

Pasteurization is a type of heat treatment that primarily destroys vegetative forms of microorganisms. In this regard, when producing high-quality pasteurized canned food, a number of additional strict sanitary, hygienic and technological requirements are imposed on raw materials. For such canned food, skin-on pork is usually used; control the pH value of the raw material (for pork the pH should be 5.7-6.2, for beef - 6.3-6.5). During the salting and maturation process, it is recommended to use brine injection, massaging and tumbler. The raw materials are packaged in elliptical or rectangular metal cans with a capacity of 470, 500 and 700 g with simultaneous addition of gelatin (1%). After pressing, the jars are sealed using vacuum sealing machines.

Pasteurization is carried out in vertical or rotary autoclaves. The pasteurization mode includes the time of heating the cans at 100°C (15 min), the period of reducing the temperature in the autoclave to 80°C (15 min), the time of pasteurization itself at 80°C (80-110 min) and cooling to 20°C ( 65-80 min). Depending on the type and weight of canned food, the total duration of the pasteurization process is 165-210 minutes; The heating period for the central part of the product at 80°C is 20-25 minutes.

During pasteurization, the product can retain heat-resistant species of microorganisms that can develop at temperatures up to 60°C, as well as thermophilic species with an optimum development at 53-55°C. To prevent an increase in the contamination of microorganisms, it is necessary to warm up and cool the jars as quickly as possible in order to “pass” the temperature optimum for the development of microorganisms. The most dangerous temperature is considered to be 50 - 68°C.

The amount of jelly in pasteurized products increases (from 8.2 to 23.8%) with increasing heat treatment temperature (from 66 to 94 °C). However, prolonged heating deteriorates the quality of not only the product itself, but also the properties of the jelly (strength, ability to gel). The use of temperatures above 100°C during heat treatment of pasteurized canned food (during the heating period) is accompanied by a deterioration in the juiciness of the product, friability, and a deterioration in consistency.

Tyndalization is a multiple pasteurization process. In this case, canned food is subjected to heat treatment 2-3 times with intervals between heating of 20 - 28 hours. The difference between tindization and conventional sterilization is that each stage of thermal exposure is not enough to achieve the required degree of sterility, however, the total effect of the regime guarantees a certain stability of canned food during storage.

With this method of heat treatment, microbiological stability is ensured by the fact that during the first stage of heating, which is insufficient in terms of the level of sterilizing effect, the majority of vegetative bacterial cells die. Some of them, due to changed environmental conditions, manage to be modified into a spore form. During the intermediate exposure, the spores germinate, and subsequent heating causes the death of the resulting vegetative cells.

Since the degree of impact of pasteurization and tindialization regimes on the components of meat products is less pronounced than during sterilization, pasteurized products have better organoleptic and physicochemical characteristics.

Pasteurized canned food is classified as semi-canned food; their shelf life is at t = 0-5°C and? not higher than 75% 6 months. Tyndized canned food, the shelf life of which at a temperature not exceeding 15°C is 1 year, is classified as “3/4 canned food”. The conditional notation of the pasteurization regime has a form similar to the sterilization formula. It includes several formulas for thermal regimes indicating the periods of holding canned food between heating. Pasteurized canned food is a delicious type of product.

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 under conditions of deep vacuum 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.

Center for Distance Education "Eidos"

MUNICIPAL EDUCATIONAL INSTITUTION

AGINSKAYA SECONDARY SCHOOL No. 2

Ivannikova Irina, 9th grade student, Aginsk secondary school No. 2

Work on mathematics and biology

Leaders: Tatyana Aleksandrovna Shindyakina, mathematics teacher; Shchedlovskaya Olesya Anatolyevna, biology teacher

RADIATION STERILIZATION OF FOOD PRODUCTS

Why I chose this topic:

I was wondering how radiation sterilization of food occurs

Target:

Find out why radiation technology for food processing has significant advantages over other known methods.

Tasks:

1. Understand the essence of radiation technology for food processing;

2. Find out what are the features of radiation processing of various products;

3. Investigate what biological changes occur in sterilized products;

Idea and problems:

Is it safe to eat products after radiation sterilization? What groups are products subject to sterilization divided into?

INTRODUCTION

There are various food processing methods:

1. Canning at high temperatures is carried out to destroy microflora and inactivate enzymes of food products. These methods include pasteurization and sterilization

2. Ultrasound preservation (more than 20 kHz). This method is used for pasteurization of milk, in the fermentation and non-alcoholic industries, and for sterilization of canned food.

3.Irradiation with ultraviolet rays (UVR). This is irradiation with rays with a wavelength of 60-400 nm. Used for surface treatment of meat carcasses, large fish, sausages, as well as for disinfection of containers, equipment, refrigerators and warehouses.

4.Use of detoxicating filters. The essence of this method is the mechanical separation of goods from spoilage agents using filters with microscopic pores. This method allows you to preserve the nutritional value and organoleptic properties of goods as much as possible and is used for processing milk, beer, juices, wine and other liquid products.

5. Aseptic canning is sterilization of the product at a temperature of 130-150 ° C with subsequent cooling; sterilization of containers by radiation treatment. This treatment is universal and is used for liquid and viscous products (milk, juices, wine, pasta, etc.). In my work, I want to dwell in more detail on the radiation treatment of food products, since radioactive substances can enter the body with food and water through the intestines . How can you protect yourself from radioactive substances, and what food products can be subjected to radiation treatment.

1.Analysis of literature found on the Internet

2.Compare search results

3. Comparison of facts

II WITH SIGNIFICANCE OF THE METHOD OF RADIATION STERILIZATION OF FOOD PRODUCTS

Preservation by ionizing radiation called cold sterilization, or pasteurization, since the sterilizing effect is achieved without increasing the temperature. To process food products, a-, P-radiation, X-rays, and a flow of accelerated electrons are used. Ionizing radiation is based on the ionization of microorganisms, as a result of which they die. Preservation by ionizing radiation includes radiation sterilization (radappertization) of long-term storage products and radurization with pasteurizing doses.

Radiation sterilization of food consists of irradiating food with ionizing radiation under the influence of cobalt or cesium isotopes in order to increase shelf life and destroy pathogens.

It is known that for various reasons: rotting, germination, spoilage by insects, a large number of food products, raw materials, seeds are lost. Thus, the use of radiation sterilization will not only increase the shelf life of certain food products, but also significantly reduce the number of possible food poisoningth

A significant disadvantage of ionizing processing of products is the change in chemical composition and organoleptic properties. In industry, this method is used for processing containers, packaging, and premises.

9. http://gyg-epid.com/2009/04/05/print:page,1,radionuklidy_v_pishhe.html

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 high 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.