Meat storage temperature. Storing raw meat in the refrigerator and freezer

Meat is one of the most common food products. In addition to the variety of prepared dishes and excellent palatability it contains minerals and a high percentage of protein. This makes its use not only tasty, but also useful, and certain climatic conditions make the consumption of meat products necessary. To preserve all the necessary qualities of meat, its culinary properties and the possibility of eating over time, it is necessary to carefully study the terms and conditions of storage. The most popular types are pork, beef and chicken carcasses.

Types of meat based on heat treatment

Meat by type heat treatment may be:

1. Fresh meat is such for 1.5 hours after the slaughter of the animal, the temperature inside the muscles of pork of such meat is within +35 - +36 degrees, and beef + 36 - +38 degrees. It is not recommended to immediately eat fresh meat, for better digestion it is necessary to stand for a couple of days.
2. Chilled meat, which, after cutting using refrigeration units, becomes inside the muscles from 0 to +4 degrees, while the muscle tissue is elastic and there is a dried crust.
3. Frozen, when the carcass is not completely frozen, but only a layer on top, not more than 25% of the entire carcass.
4. Frozen. In the thickness of the muscles, it has a temperature of no more than -8 degrees. Proper freezing prevents spoilage of meat.

The most reliable and common storage methods fresh meat are cooling and freezing. However, these processes have certain features, such as temperature and shelf life, without which the meat deteriorates and loses its nutritional qualities.

Chilled meat storage

Chilled meat that has not been subjected to quick freezing. It has more nutritional value and better taste properties than frozen. It is obtained after butchering carcasses and cooled in cold rooms before desired temperature. Its distinguishing features are a drying crust and elastic carcass muscles. Due to the fact that the cooling process does not greatly affect the quality properties of meat, this method of preservation is given priority during production. However, chilled meat has a relatively short shelf life (several hours).

Cold storage

Shelf life at temperatures from +2 to 0 degrees:

• Pork no more than a day;
• Beef no more than a day;
• Chickens for a maximum of 5 days. If the constant temperature of the refrigerator is 0 degrees, then the shelf life is no more than 15 days.

It is not recommended to store meat in a plastic bag; it is better to use enameled, plastic dishes or glass containers. It is also not advisable to use wooden bowls, as they will absorb the meat juice. No need to tightly close the lid, it would be more correct to cover with a napkin or towel. It is important to know that boneless meat has a longer shelf life than bone-in meat, and a whole piece is better stored than finely chopped pieces. Storing separately from other products will extend its life.

Shelf life at temperatures from 0 to -2 degrees:

• Pork maximum 12 days;
• Beef no more than 16 days;
• Chicken no more than 3-4 days.

In a frozen state at a temperature regime of -2 to -3 degrees, the shelf life of pork and beef is a maximum of 20 days, and chicken carcasses up to 14 days.

Storage in freezers

If necessary, increase the period of storage of meat, it is frozen. However, the conditions of this method reduce the nutritional and taste value and have a number of other disadvantages, such as weight loss due to moisture evaporation, dehydration and porosity of the product. But despite this freezing allows you to eat and retain the taste properties of meat for a longer period.

The term and storage conditions of frozen meat also depend on the temperature and specific types:

• At a temperature of -12 degrees:
• Pork up to 3 months;
• Beef up to 8 months;
• Chicken 4-5 months old.

At a temperature of -18 degrees:

• Pork up to 6 months;
• Beef up to 13 months;
• Chicken no more than 7-9 months.

At -30 degrees:

• Pork no more than 15 months;
• Beef no more than 2 years;
• Chicken up to 12 months.

Shelf life in store refrigerators:

• At a temperature of 0 degrees - no more than 5 days;
• At temperatures from 0 to +6, a maximum of 3 days;
• At temperatures from +6 to +8, a maximum of 2 days.

In addition to compliance temperature regime during storage, it is also necessary to monitor other indicators, such as:

1. Relative humidity, its norm should be at least 85%. Humidity is affected by air temperature;
2. Air flow (circulation), correct value 4-6 air volumes per hour.

• Frozen meat should not be re-frozen, this negatively affects its shelf life, nutritional properties, can lead to damage and harm human health. Therefore, compliance simple rules allows you to properly store the meat for a long time.
• It is impossible to wash the meat before freezing, it can deteriorate, it will be enough to wipe it well;
• For convenience in cooking, divide the meat into portions in order to defrost as much as necessary, and not the whole piece;
• You can wrap the cut meat pieces in foil or paper and place them together in a plastic bag, trying to release all the air from there;
• If you attach a note with the freezing date to the same package, this will allow you to control the shelf life;
• Fold all the freezer compartment and set the desired temperature conditions;
• When the meat has become firm, you can take it out of the freezer and dip it completely in cool water, then place it back in the freezer. This forms a crust of ice that will retain more moisture and the meat will remain juicy, no matter how long it is stored.
• When freezing, it is better to immediately expose the most cold temperature for the entire period of storage in the freezer, for the speed of the process. Because with gradual freezing, ice crystals spoil the meat fibers and this further, already during cooking, prevents the absorption of liquids, which worsens the taste of meat dishes.

It is highly undesirable to defrost meat using a microwave or hot water, this makes it more rigid and spoils the taste. To preserve juiciness, it is better to defrost meat in the air at room temperature although the process will take longer. If it is hot at home, in order not to leave the meat for the whole day, you can transfer it from the freezer compartment to the refrigerator for gradual thawing.

Proper storage food products ensures the preservation of their food and biological. values, protects against damage, and also has great importance in the prevention of food poisoning of a bacterial nature (see Food poisoning). Microorganisms that cause these poisonings can multiply profusely in products when stored in room conditions; at the same time, for some time, food products and ready meals contaminated with microorganisms and their metabolic products (toxins) do not change appearance and taste, producing, thus, the impression of benign and quite suitable for consumption. Measures to prevent the reproduction of microorganisms in food products are reduced to storing them in the refrigerator, selling them within the recommended time frame and observing the dignity, gig. storage space requirements. Cold prevents the vital activity of microorganisms, and rapid implementation reduces the possibility of abundant accumulation of microorganisms and their toxins. Of course, when the deadlines and other conditions are violated, X. p. p. food poisoning. However, it must be remembered that a person who violates the conditions of correct X. p. p. exposes himself to great danger, since food poisoning, as a rule, is difficult, fraught with serious complications, and sometimes ends in death.

The conditions and terms of X. p. p. depend on the type of product and the way it is processed. In addition, the conditions of cold storage in the city, in the absence of a refrigerator, are less favorable than in rural areas, where residents for long cold storage can equip special rooms(subfloors, glaciers, etc.).

Storage ready meals. Many ready-made dishes (broths and first courses in meat, fish or mushroom broth, second courses of meat, poultry, fish, stewed vegetables, mushroom dishes, cold dishes - jellies, jellied meat and fish, vinaigrettes, salads, as well as confectionery with cream) refer to perishable products. Strong meat, fish, mushroom broths, frozen decoctions of jellied dishes, vinaigrettes and salads seasoned with butter, sour cream or mayonnaise, creams are a good breeding ground for microorganisms, which multiply very quickly in them. Therefore, the listed dishes after cooling should be stored on the lower or middle shelf of the refrigerator at a temperature of 4-6 °C; after 4-6 hours. storing these foods at room temperature is dangerous to eat. It should be remembered that the first and second courses can be stored in the refrigerator for no more than 72 hours. If the dishes are prepared for future use, then before serving, not all the prepared dish should be boiled or heated in a pan, but only the part that will be sold. However, it must be borne in mind that vitamins are partially destroyed with each boiling and heating. In this regard, the preparation of dishes for the future in in large numbers Not recommended. Aspic dishes should be stored in the refrigerator for no more than 48 hours, jellies and mushroom main dishes are recommended to be sold within 24 hours, pastries and cakes (cooked at home or purchased in a store) with protein-whipped cream or fruit trim can be stored in the refrigerator for no more than 72 hour, with butter cream - 36 hours, with custard- 6 o'clock. At storage of ready food it is necessary to observe a dignity strictly. requirements: maintaining the cleanliness of the storage area, storage in clean dishes and packaging, avoiding contact of ready-made meals and products eaten without additional processing (sausage, cheese, cottage cheese, etc.), with raw products and semi-finished products, as well as with contaminated products (vegetables, etc.).

Storage of meat, fish, meat and fish products. Of the meat and fish products, the most perishable are semi-finished products (with the exception of dumplings, which can be frozen) and offal (except for the tongue, which can be stored like regular meat). There is no need to buy semi-finished products in advance and they should be stored only in a refrigerator at a temperature of 0 to 8 °C. In the case of freezing, the taste qualities of semi-finished products and by-products deteriorate significantly. The following periods of storage of semi-finished products and offal in the refrigerator are recommended: semi-finished meat products(beef steak, entrecote, langet, etc.) - 36 hours, breaded (schnitzel, rump steak, etc.) and small-sized (beef stroganoff, goulash, stew, etc.) semi-finished meat products - 24 hours, cutlets, steaks chopped, liver, kidneys, brains, etc. - 12 hours, chopped meat, cabbage rolls, peppers, zucchini stuffed with meat and rice - 6 hours; semi-finished products from poultry: natural fillet - 48 hours, breaded fillet - 2 * 4 hours, chopped cutlets, offal - no more than 12 hours. Semi-finished fish products have the shortest shelf life. So, for example, fish semi-finished products breaded in breadcrumbs can be stored for no more than 24 hours, fish cakes - 12 hours, fish semi-finished products of special cutting - no more than 3 hours.

Meat, fish, poultry in its natural form should not be stored at room temperature. In a refrigerator at a temperature of 0 to 8 °C, fresh and chilled meat and poultry can be stored up to 72 hours, fish - 48 hours, frozen meat and poultry - up to 5 days, ms-broken fish - up to 3 days. When frozen meat, fish or poultry is placed in a freezer, their shelf life is significantly extended. Meat, poultry, fish can be stored for a long time in specially equipped glaciers. In case of defrosting, regardless of subsequent storage conditions, meat, fish and poultry must be sold in within 24 hours.

The shelf life of sausages, sausages, hams and smoked meats depends on the method of their manufacture. Boiled stuffed, liver, black puddings, sausages, sausages, boiled hams, boiled pork, etc. at home should be stored only in the refrigerator at a temperature of 0-8 ° heat. With this boiled sausage of the highest grade, boiled ham, boiled pork, roll in a piece (not cut) can be stored for 72 hours, boiled sausages of the 1st, 2nd and 3rd grade sausages and sausages, liver and blood sausages and brawns of the 1st and 2nd grades - 48 hours, liver sausages, blood and brawns of the 3rd grade must be sold within 12 hours. Semi-smoked and boiled-smoked sausages can be stored for up to 3 days at a CC: :-at temperature (not higher than 20 °) for up to 3 days; The same shelf life is acceptable for smoked meats (smoked "rolls", ham, brisket, etc. \ The shelf life of raw smoked stakes "=: when placed in a cool, dry place is not limited. However, you need to: know that when it appears on the shell of a loaf of mold sausage should be rubbed with a clean cloth, abundantly moistened with 20% solution table salt or 3% solution of acetic acid, and then dry. When removing mold, you should try not to damage the shells of the loaf. Once the mold has been removed, the sausage can no longer be stored. Sometimes, during long-term storage, a white dry coating of table salt appears on the surface of a loaf of raw smoked sausage. Such a coating is not a drawback of the product, does not reduce its taste, and it can not even be removed. Raw-smoked, boiled-smoked and semi-smoked sausages, as well as other smoked meats, cut into slices and packed under vacuum in a polymer film, can be stored at a temperature of up to 20 ° (without opening the package) for up to 4 days, in the refrigerator - up to 6-7 day

Salting, marinating and smoking increases the shelf life of fish products. The shelf life of salted fish depends on the degree of salinity: lightly salted fish (6-10%) can be stored in the refrigerator for up to 6-7 days, medium and strong salted - for a longer period. Hot-smoked fish is stored in the refrigerator for up to 3 days, cold-smoked - 8-10 days; dried fish is stored in a cool, dry place, periodically inspecting it to detect moldiness. Removing mold from dried fish carcasses is done in the same way as from smoked sausage loaves. Moldy carcasses are not subject to further storage. Salt deposits do not affect the quality of dried fish.

Storage of milk, dairy products and eggs. All dairy products are best stored in the refrigerator. Fresh milk in any container should be stored for no more than 36 hours, boiled milk - up to 3 days, lactic acid products (kefir, yogurt, acidophilus) - 36 hours, sour cream - up to 3 days, cottage cheese and cheese curds - 36 hours, sweet creamy cheeses in polymer packaging - up to 48 hours. Butter in the refrigerator at temperatures above 0 ° is stored for up to 10 days, freezer- more long time, cheeses - up to 15 days, chicken eggs - up to 20 days.

Storage of vegetables, fruits and berries. At home, at room temperature, ripe vegetables, fruits and berries deteriorate relatively quickly. Usually, after 12-24 hours, berries begin to turn sour, especially strawberries, strawberries and raspberries, tomatoes and food greens quickly rot. Ripe apples, pears, oranges at room temperature, in the absence of damage, can be stored for 2-3 days. Washed vegetables and fruits rot in 6-12 hours. Root crops (potatoes, beets, carrots) can be stored at room temperature in a dry place for up to 10-14 days. However, beets and carrots can dry out, losing taste and vitamin value. In a warm room, germination of potato tubers can occur, accompanied by an increase in their content of the toxic substance solanine, which can cause severe poisoning.Mature watermelons, melons, pumpkins can be stored at room temperature for 10 or more days if their peel does not have abrasions and damage ; at the same time, melons are more prone to spoilage. Onion and garlic in a dark dry place at room temperature can be stored for 1 month. and more.

Long-term storage of fruits and vegetables in urban conditions is only possible in a refrigerator at a temperature of 1-2°C. At the same time, they should not be frozen at home, because after thawing they quickly rot, and their taste and vitamin value are significantly reduced. Vegetables and fruits should be selected for storage in the refrigerator good quality, without damage to the surface, not sluggish, not frozen. Vegetables and fruits in the refrigerator should be kept clean (but not washed) by placing them in a container with a lid or a plastic bag. Refrigerator shelf life has not been established for most vegetables and fruits, but stored vegetables and fruits should be checked regularly: if areas of softening, spots on the skin and other early signs of spoilage appear, further storage is not recommended. It is also not recommended to store berries and food greens in the refrigerator for more than 24-48 hours.

In rural areas, vegetables and fruits can be stored much longer if there are special facilities for their storage. However, one of the main conditions proper storage vegetables and fruits is to ensure a constant temperature and humidity.

After harvesting for personal plot fresh vegetables stored in cellars and undergrounds. In order for vegetables to be preserved during the winter, the temperature in warehouses should ". be 0-2 °. At 5 ° some vegetables begin to germinate and deteriorate. Especially important is the creation right conditions long-term storage of potatoes. It should be stored in a cool, dark place, out of direct sunlight.

Fruits (apples, pears, etc.) are best stored separately from vegetables, as they quickly absorb odors and change their taste. Optimal conditions storage of fruits are as follows: temperature in the range from +2 to 0 °, relative humidity in the range from 85 to 95%, regular supply of fresh air.

For a longer and more reliable storage of vegetables and fruits, various ways their processing: pickling, salting, fermentation, soaking, canning with sugar, drying, sterilization, pasteurization. You can preserve vegetables and fruits at home. rules home canning, providing the possibility of long-term storage of vegetables and fruits - see the article Home canning.

Storage of canned goods. Sterilized canned food, both factory-made and home-made in hermetically sealed jars, can be stored for a long time at normal temperature. Do not store canned food at elevated temperatures (in hot rooms, near heaters, etc.). Fruit preserves - jams, jams, juices, syrups - in storage

in a hot room they darken, change color, canned food in unvarnished tin cans acquire an unpleasant, metallic appearance. smack.

Canned foods should not be allowed to freeze. With subsequent defrosting, their taste, especially canned fruits and vegetables, deteriorates significantly, mashed potatoes separate, syrups and marinades become cloudy, vegetables and fruits become flabby and tasteless. Storage at low temperatures canned food with a high sugar content (jam, jams, condensed milk, etc.) leads to their sugaring. Freezing canned food during storage is also undesirable because this increases the volume of the contents, which leads to bursting of cans, swelling of their lids, divergence of seams, and glass jars may have lids torn off.

Store canned food in a dry place.

special attention require unsterilized canned food in tin and glass jars- so-called conserves. As a rule, these are fish snack products - sprats, marinated herring, etc. They are stored at a low temperature, but not below 0 °. In hot weather, without a refrigerator, they should not be stored for more than 2-3 days. The conditions and terms of storage of preserves are usually indicated on the label or lid of the jar. After opening, the shelf life of the canned product does not exceed the shelf life of the corresponding product that has not been preserved. For example, the shelf life of condensed milk after opening a can in the refrigerator at a temperature of 0 to 8 °C is no more than 72 hours, canned meat - up to 48 hours. etc. At the same time, canned meat, fish and vegetable should be immediately transferred from cans to glass or enameled dishes.

Dry food storage. Dry foods (flour, cereals, pasta, dried fruits, granulated sugar) can be stored for quite a long time. However, their storage without signs of damage is possible only if certain rules. Dry bulk products should be stored in dry, well-ventilated areas. An increase in the products of moisture St. 15% contributes to their deterioration. Humidification of products occurs when stored in unventilated rooms, in basements as well as sudden changes in temperature. You can store dry products in paper bags, linen bags, as well as in special. jars with lids produced by the industry. In order to avoid deterioration in the taste of dry products (rancidity of millet, etc., and the appearance of various pests of dry products, which happens during their long-term storage), one should not make large stocks of these products, renewing them as they are spent. Dry products easily perceive and retain foreign odors for a long time, which should also be taken into account when placing them for storage.

Storage of bread and bakery products. Bread and bakery products should be kept in a special bread bins produced by industry, or in enamelware with lid. rye and wheat bread better to store separately. Storing bread in plastic bags protects it from drying out, but contributes to the appearance of foreign odors and moisture, therefore such bags are recommended only for short-term storage

Brief lecture notes

Storage conditions - a set of external influences environment, due to the mode of storage and placement of goods in the warehouse.

Storage mode - a set of climatic and sanitary-hygienic requirements that ensure the preservation of goods. It can be distinguished, climatic and sanitary-hygienic storage regimes.

Requirements for the climatic regime of storage include requirements for:

1) temperature;

2) relative air humidity;

3) air exchange;

4) gas composition;

5) illumination.

Storage temperature– air temperature in the storage. This is one of the most significant indicators of storage mode. With an increase in temperature, chemical, physicochemical, biochemical and microbiological processes intensify.

According to the van't Hoff rule, the rate of chemical processes increases by 2-3 times with every 10°C rise in temperature.

Since the ability of products to preserve is due to the slowdown of all the processes occurring in them, for most goods, lower storage temperatures close to 0 ° C are preferable than higher ones.

For many products stored at low temperatures, the lower limit is limited by the freezing point, if certain consumer properties deteriorate during freezing. This applies primarily to those products, which include water.

When water freezes, the microstructure of the product, and sometimes the packaging, is destroyed, as a result of which microcracks are formed, cells are destroyed. Goods with a homogenized structure delaminate when frozen, as a result of which they lose marketable condition(milk, dairy products). In some drinks at temperatures close to freezing, a precipitate forms (for example, in wine).

For frozen products, there is no such pronounced lower temperature limit. They can be stored in the temperature ranges: -10…-12; -23…-25; -30…-40°С. At lower temperatures, intense sublimation of ice and strong dehydration of the product are noted. However, for frozen products, the upper temperature limit is limited (not higher than -8 ° C), since at higher temperatures, ice recrystallizes and crystals coarsen. As a result, the quality of the product deteriorates during defrosting.

Products that do not contain free water can be stored without spoilage at very low temperatures (groceries).

At the same time, there are products that, due to preservatives or preservative effects, can be stored at a fairly wide range of temperatures (high and low).

There is no single optimal storage temperature for all consumer goods due to the variety of properties that ensure their preservation.

In this regard, all consumer goods are divided into six groups according to their thermal state and requirements for optimal temperature conditions (Table 1).

Table 1 ranges optimal temperatures are exemplary.

For each assortment group or even type of consumer goods, limiting temperatures are set (not higher and / or not lower) in standards and / or sanitary rules. SanPiNs regulate the conditions (including temperature and relative humidity) and the shelf life of especially perishable goods.

Relative air humidity (RHV) – an indicator characterizing the degree of saturation of air with water vapor.

RHV is defined as the ratio of the actual content of water vapor in a certain volume of air to the amount that is necessary to saturate the same volume of air at the same temperature.

RHV indirectly indicates a shortage of water vapor in the environment. Since the equilibrium state is the most stable, and an unstable state is created with a lack of water vapor, water evaporates from more humid objects.

Table 1 - Classification of goods by thermal state and

requirements for optimal temperature conditions

Evaporation of water from goods leads to quantitative and qualitative losses, in particular to natural loss due to shrinkage and wilting, resulting in increased waste.

The higher the moisture content of the goods and the lower the RHV, the greater their losses. Therefore, goods from high humidity it is recommended to store at high RHV.

However, such a humidity regime is unsuitable for dry goods, as they can absorb water vapor, get wet and be subject to microbiological deterioration.

The choice of humidity storage mode is also influenced by the ambient temperature and the presence of protective, moisture-proof shells in the product.

RHV is inversely related to temperature. As the temperature increases, the moisture content of the air increases and, consequently, the RHV decreases. This increases the absolute humidity (the actual content of water vapor in the air).

At temperatures below the dew point, the absolute humidity is higher than the water vapor content required for saturation. As a result, excess vapors fall out in the form of condensate on containers, products, as well as on the walls and ceilings of storage facilities. With the appearance of drip-liquid water on the surface of the goods, microbiological spoilage is accelerated, as well as corrosion of metal surfaces.

Protective shells - sealed packaging, paint coatings, shrink films, wax, paraffin - prevent drying or moistening of goods. At the same time, the precipitation of condensate on the surface of these shells can lead to their gradual destruction.

Thus, the choice of the optimal RHV is determined primarily by chemical composition goods, their hygroscopicity, storage temperature, the presence of protective shells. RHV, like temperature, is the most significant indicator of storage mode. It is regulated by GOSTs and SanPiNs. However, for some groups of goods, the standards do not indicate specific RHV values, but only the need for storage in dry, ventilated warehouses. For many food products, the RHV range is set depending on the storage temperature.

Depending on the requirements for optimal humidity conditions, all consumer goods can be divided into four groups (Table 2).

Table 2 - Classification of goods by humidity and requirements for

optimal humidity conditions

In addition to the actual values ​​of RHV and temperature importance for the preservation of goods, it has the stability of the temperature and humidity regime, which is characterized by the absence of sharp jumps in the regime indicators. Such fluctuations have a stronger negative effect on the shelf life of many products than a small increase in temperature.

The stability of the temperature and humidity regime can be ensured by optimal air exchange.

Air exchange (V/R)- an indicator of the regime, characterizing the intensity and frequency of air exchange in the environment surrounding the goods.

In the process of air exchange, a uniform temperature and humidity regime is created, and gaseous substances emitted by stored products, containers, equipment, etc.

Air exchange is characterized by the speed of air movement in the warehouse and the frequency of its exchange. It can be with air supply from the outside and in this case it is called ventilation, air exchange without outside air supply due to air movement in the warehouse is circulation.

Depending on the method of stimulation, two types of air exchange are distinguished: natural and forced.

Natural air exchange is carried out due to the difference specific gravity cold and warm air. Cold air is heavier and moves downward, displacing warm, lighter air. Both circulation and ventilation can be natural.

The intensity of natural air exchange depends on the temperature difference between cold and warm air. A noticeable movement of air is observed at a temperature difference of at least 8 ° C. The greater this difference, the more intense the air exchange.

Forced air exchange is carried out by supplying and / or exchanging air in the warehouse with fans.

According to the direction of the air flow in relation to the commodity mass, general and active air exchange is distinguished.

With general air exchange (ventilation or circulation), air moves only in the warehouse space free from cargo. There is no stimulating air supply to the mass of stored goods.

This air exchange allows you to create a uniform temperature and humidity conditions in different points cargo-free space.

It is used for most consumer products that either do not emit heat during storage (do not self-warm), or emit physiological heat in a small amount. For food products, prone to self-heating due to physiological heat, often use active air exchange.

Active air exchange is the exchange of air by its stimulating supply through the commodity mass. With the help of active ventilation or circulation, a uniform temperature and humidity regime is ensured in the mass of stored goods due to the periodic removal of excess heat and water vapor, as well as surface drying, which improves the shelf life of goods.

However, active air exchange is not suitable for all products, since with intensive removal of water vapor, wilting occurs and the aroma is lost. In addition, the method is costly. In practice, active air exchange is used when storing grain, potatoes, root crops, white cabbage.

Gas composition of air– mode indicator characterizing the composition of gases in the environment. It is due to three groups of components:

1) the main gases are oxygen, nitrogen and carbon dioxide;

2) inert gases - hydrogen, helium, argon, etc.;

3) harmful gaseous impurities - nitrogen oxides, as well as ozone, ammonia, freon, etc.

Oxygen and nitrogen predominate quantitatively. The normal gaseous environment (NGS) contains (in%): oxygen - 20.6; nitrogen - 78; CO 2 - 0.03. The content of inert gases is about 1%.

The amount of harmful gaseous impurities is individual for different storage facilities and depends on the degree of outdoor air pollution by industrial waste, gaseous refrigerants and other substances. When ventilated with outdoor polluted air, they enter the warehouse and change the gas composition of the air.

In addition, some goods emit gaseous substances during storage (carbon dioxide, ethylene, aromatic substances, volatile acids, etc.), which also affects the gas composition of the air in the warehouse.

The preservation of goods is most affected by oxygen, carbon dioxide and gaseous impurities.

Oxygen enhances oxidative processes: fats go rancid, vitamins are destroyed. Thus, oxygen tends to have a negative effect on the shelf life of many commodities. At the same time, its absence or deficiency can cause anaerobiosis (suffocation) of living objects (fruits, vegetables, grains, etc.). In addition, in the absence of oxygen, anaerobic microorganisms are activated, causing spoilage of a number of products.

Carbon dioxide, which has antiseptic properties, inactivates the development of foreign microflora and, up to certain concentrations, improves the preservation of goods. However, its excess can cause physiological diseases. For example, for most fresh fruits and vegetables, the maximum concentration of CO 2 in the air is 8-10%.

It is possible to control the shelf life of some types and varieties of fruits and vegetables by regulating the gas composition of the air in the storage: the concentration of O 2 decreases, but not lower than 2%, and the concentration of CO 2 increases to 2-5%, but not more than 8%. The method is called gas storage and has two varieties:

1) with a controlled gas environment (RGS);

2) modified atmosphere (MGS).

Other components of the gas composition - nitrogen and inert gases, according to currently available information, do not affect the shelf life of consumer products.

The effect of harmful gaseous impurities on the shelf life of products has not been studied. There is only information about the effect of ethylene, which is released during storage of fruits, on the processes of their ripening, as well as delaying the germination of potatoes. It has also been established that ozone in certain concentrations improves the preservation of sausages, cheeses, potatoes, carrots, apples, cabbage, etc.

It can also be assumed that the presence in the air of a series harmful impurities(oxides of sulfur, nitrogen, ammonia) leads to contamination of goods and causes changes in their consumer properties. Food contamination with these impurities can lead to loss of safety.

Studies to establish the effect of harmful impurities on the shelf life of consumer goods have almost not been carried out, therefore, in the scientific and practical literature there is no information on this issue.

illumination- an indicator of the storage mode, characterized by the intensity of light in the warehouse. Light, especially sunlight, has a negative effect on the shelf life of most goods, as it activates oxidative processes, as a result of which rancidity of fats, the destruction of dyes, vitamins and other valuable substances are noted.

The requirements for the sanitary and hygienic regime of storage are characterized by a complex indicator of purity, which includes a number of single indicators.

Purity- the state of storage facilities and the environment, which is characterized by pollution that does not exceed established standards.

Purity is determined by two groups of indicators:

1) indicators of purity, differing in the nature of pollution: mineral, organic, microbiological or biological;

2) a group of cleanliness indicators characterizes the location of pollution: air, floor, equipment, mechanisms, goods, containers.

Pollution of mineral origin. Their source is mainly the soil that enters the storage with goods, containers, vehicles.

At the same time, food products may lose safety if the dust contains harmful substances(for example, radioactive elements, lead oxides, pesticides).

Therefore, the set of measures to create and maintain a sanitary and hygienic regime includes periodic wet cleaning premises (the frequency of cleaning is determined by SanPiNs or internal regulations).

Pollution of organic origin fall into warehouses along with the soil ( organic fertilizers, impurities, pesticides, etc.), so they have common sources with mineral pollution. Along with this, some goods themselves can serve as sources of organic environmental pollution (plant protection products, flour, starch, etc.). To prevent organic pollution of the environment of warehouses, it is necessary to use packaging that reliably protects against the ingress of dust-like particles of goods into the air.

Another source of organic pollution is spoiled, low-quality goods that are not removed from the warehouse in a timely manner. This source is the most dangerous, since along with organic contamination of containers, floors and equipment, microbiological contamination increases.

Pollution of microbiological origin has sources similar to other types of pollution. However, in this case, it is not so much dust-like particles coming from the soil or air that are of paramount importance, but the goods themselves and containers contaminated with pathogens of various microbiological diseases. It is from spoiled goods that such microorganisms get on containers, equipment, and then into the air. Contaminants of microbiological origin are assessed qualitatively (types of microorganisms) and quantitatively.

Each product must be stored at the required temperature certain time. Compliance with storage conditions will preserve the quality characteristics of products and their beneficial features. The function of creating the required temperature regime lies on. Modern refrigeration units can maintain any temperature in food storage rooms from -30°C to +18°C. Producers, sellers and consumers need to comply with food storage conditions, as people's health depends on it. In addition to the required temperature and shelf life, other conditions must also be monitored: cleanliness in the storage chambers, the rules for the commodity neighborhood of products and their proper placement and stacking in refrigerators.

Consider the storage conditions for the most common products in Chelyabinsk and the region.

Meat storage temperature and meat products.

After slaughter, fresh meat should, as soon as possible, be placed in. Having cooled it to a temperature of 0 ... -1 ° C, the meat can be stored for two weeks. By quickly freezing it in freezing chambers and storing it at a temperature of -18 ° C, the shelf life of meat increases to 10 ... 12 months. You can further increase it by lowering the storage temperature to -25°C. Similar conditions for temperature and shelf life of frozen poultry meat.

Chilled meat at a temperature of +1°C ... +6°C is stored for up to three days.

Chilled poultry meat can be stored for up to three days at -2°C…0°C.

Other storage conditions for meat products.

Boiled sausages, frankfurters, sausages should be stored at a temperature of +1°C…+8°C for five days. Cooked-smoked sausage can be stored at +5°C…+8°C for up to eight days and up to one month at a temperature of 0°C…+4°C. Semi-smoked sausage has a longer shelf life; at +5°C…+8°C it can be stored for 12 days. Also, semi-smoked, boiled-smoked and raw-smoked sausages can be stored at room temperature +18°C for up to 6 days.

Meat offal is mainly stored frozen at -18°C, with a shelf life of up to four months. At 0°C, by-products are stored for three days.

Storage temperature of jelly, fat, meat broth from +1°C to +6°C, shelf life - 2…4 days.

Freezing and storage of meat and meat products under the given operating modes takes place in refrigerators and freezers, using.

fish storage temperature.

Freshly caught fish must be immediately processed or frozen in freezers. Frozen fish and other seafood are stored at -18°C and below for six months, and at -10°C - only up to three weeks.

The storage temperature of caviar is -6°C.

Hot smoked fish can be stored for up to three days at -1°C to 0°C. Cold-smoked fish is stored for up to two months at a temperature (inside the product) -1°C…-5°C. Dried fish at +5°C…+8°C can be stored for up to seven months. Salted fish should be stored at a temperature of -2°C…-8°C, while its shelf life can be up to six months.

Boiled seafood is stored at +2°C…+5°C.

Compliance with a constant required temperature during the storage of fish and seafood is achieved by using refrigeration units.

Storage temperature of milk and dairy products.

In the production of dairy products, fresh milk is exposed to artificial cold from the moment of milking to getting on the store counter.

The storage temperature of milk is +4°C, while fresh milk can be stored for a day, pasteurized - up to 3 days. Butter can be stored in two forms: frozen and not. Frozen butter at -12°C can be stored for up to ten months and ten days at +6°C. Margarine can be stored much longer at the same temperatures: +1°C…+4°C - 2 months and -12°C - three months.

Storage temperature of sour cream, kefir, yogurt, cheese, cottage cheese +1°C…+6°C.

Ice cream is best preserved at an air temperature of -24°C, while its shelf life is 2…3 months.

Liquid cooling systems (chillers) are widely used in the milk production process. Cooling chambers are used to store finished dairy products.

Storage temperature of vegetables, fruits and berries.

The optimum storage temperature for vegetables, fruits and berries is between -1°C and +12°C.

Cherries, cabbage, apples, pears, peaches, onions, and garlic are perfectly preserved at -1…0°C.

Apricots, plums, grapes, melons, tomatoes, carrots, strawberries are stored at a temperature of 0°C…+1°C.

Oranges, tangerines, lemon should be stored at +2°C.

Potatoes are stored at +4°C.

Cucumbers, eggplants, peppers are stored at +10°C.

Bananas and pineapples are stored at +12°C.

To preserve the freshness of fruits and vegetables, modern chambers are being built.