The use of external factors in food storage. Summary: Methods and conditions of food storage, their influence on the shelf life. The concept of storage and methods of storing products

5.1 The concept of storage and methods of storing products

5.1.1 Storage as a preliminary step in food production

Storage - the stage of circulation of goods, starting from the release finished products before consumption or disposal. During the storage of food products, various changes occur in their composition and quality, which can be slowed down, strongly slowed down, but cannot be completely avoided. Depending on the nature of these changes, the processes occurring during storage can be divided into physical, chemical, biochemical, microbiological, biological.

Physical processes (humidification and drying) change the state and properties of products, and also affect the activity of other processes. These changes can be slowed down by temperature conditions, relative humidity of the air, as well as the correct selection of packaging.

Chemical processes occur in food products without the participation of enzymes (caramelization of sugars, rancidity of fats, chemical bombing of canned food). The speed of chemical processes is slowed down by lowering the storage temperature, the use of packaging that isolates the product from the action of light and atmospheric oxygen.

Biochemical processes are due to the action of enzymes found in products. Biochemical processes are respiration, hydrolysis (autolysis), as a result of which there is a loss of solids, moisture and self-warming (grain, vegetables), i.e., the content of sugars, acids, proteins, fats, vitamins, etc. decreases, thus reducing food biological value of the product. Breathing can be slowed down by lowering the temperature and humidity of the air.

Microbiological processes are caused by the vital activity of microorganisms, for which many foodstuffs serve as a good nutrient medium. These include fermentation, mold, rotting.

Fermentation is the decomposition of carbohydrates and some alcohols under the action of enzymes secreted by microorganisms. During the storage of food products, the following most often occur: alcohol, lactic acid, acetic acid, butyric fermentation.

Molding occurs as a result of the development of food products (fruits, vegetables, bread, meat, fish products, etc.) of mold fungi. The development of molds causes the appearance of a peculiar musty smell, plaque on the surface of the product and the accumulation of toxins (poisonous substances).

Putrefaction is the decomposition of proteins by the action of enzymes secreted by putrefactive microorganisms, with the formation of substances that have an unpleasant odor and are poisonous. Most often, foods rich in protein are prone to rotting: meat, fish, eggs.

Biological processes are processes caused by biological objects (rodents and pests) that cause great damage to goods during storage: destroy and contaminate them with their secretions, are sources and vectors of microorganisms. Therefore, when storing all food products, it is necessary to observe a sanitary regime, to carry out disinfection of storage facilities.

Loss of food products. During storage, transportation and sale, quantitative losses of goods occur, which are divided into normalized and acted. Normalized losses include natural weight loss and pre-sale waste generated during the preparation of goods for sale (cleaning sausages, fish, butter; the formation of crumbs during the sale of refined sugar, confectionery, etc.)

Natural decline- is the loss of mass of goods arising from natural causes. Its main reasons are shrinkage, spraying (crushing), leakage, crumbling, etc. The size of the natural loss of products is affected by physicochemical characteristics goods, terms and conditions of storage, type of packaging, climatic conditions and seasons. Waste from cleaning the top layer (staff) of butter does not belong to natural wastage; waste generated during the preparation for the sale of sausages (string, ends of casings), broken poultry(paper).

Loss of goods - Scrap, battle, resulting from an unfair attitude, also do not apply to natural loss and are written off at the expense of the perpetrators. Write-off of the shortage can be made only after the inventory of goods. The procedure for writing off shortages, theft and losses from damage to valuables is regulated by law and the constituent documents of the enterprise.

5.1.2 Storage methods: concept, their classification according to the methods of regulating storage factors

Temperature

United optimal temperatures no food storage. Most prefer temperatures close to 0°C. However, according to temperature storage products are divided into:

Frozen (meat, fish, frozen fruits and vegetables, animal fats, cow butter). The storage temperature range for them is from -10°С, -12°С to -25°С;

Supercooled (salted fish, raw smoked sausages, animal fats) are stored at temperatures of -2°C, -7°C;

Chilled (fruits and vegetables, pickled products, cakes, pastries). Storage temperature for them is –1, +1°С, 0, +6°С;

Moderate (alcoholic, non-alcoholic drinks). Temperature not higher than 12°С;

Wide-range (alcohol, vodka, groceries, canned food, jam, jam, marmalade, vegetable oil). Storage temperature 0 +25°С.

Air humidity

The choice of humidity storage mode is influenced by temperature, product properties, package tightness, etc.

According to this factor, there are:

Dry foods (groceries, dried fruits). They are stored at a relative air humidity of not more than 65%;

Moderate (confectionery, wine, tea, coffee) - humidity not higher than 70% -75%;

Humidity (dairy, meat, fish products, eggs, onions, garlic) - 80-85%;

High humidity (fruits and vegetables, meat, fish) - 90-95%.

Air exchange and gas composition of air

An important indicator of the storage mode, which creates a uniform temperature and humidity exchange, are removed gaseous substances allocated by the stored goods. An increase in the amount of oxygen in the air (above 20.6%) enhances oxidative processes, rancidity, etc. Lack of it leads to suffocation of vegetables, mustiness of flour, etc.

Therefore, when storing products, forced or natural circulation air.

Microbiological contamination of air and biological contamination

This factor is an indicator of the cleanliness of the premises, if not observed, the product may lose safety. Therefore, it is necessary wet cleaning premises, disinfection, disinfestation and deratization.

sunlight

It has a negative effect on the product, activating oxidative processes, causing cloudy drinks. Therefore, most products are recommended to be stored in a darkened room.

Placement of goods

When placing goods for storage, the following requirements should be taken into account:

· safety, rationality of operation of storages;

Compatibility of goods - rules of product neighborhood;

· efficiency of work - provision of means of mechanization, heating devices, etc.

Product Neighborhood Rules

Products not stored together:

chilled and frozen;

dry and wet

· with pungent odors and easily perceived it.

For example, tea - with spices; butter - with fish, paints, etc.

Violation of this rule leads to the appearance of defects, reduces quality gradations, and leads to losses.

Fundamental principles of storage:

Continuity of compliance with storage conditions;

care of goods during storage;

Systematic control over the goods, mode, terms of storage;

selection of methods and terms of storage at the lowest cost ( economic efficiency storage).

Shelf life

An integral element of the storage of goods are expiration dates. They are set depending on the characteristics of the goods, the expiration dates are divided into:

Perishable. These are products with a shelf life of several hours to several days. The expiration dates for them are regulated by sanitary and epidemiological rules and regulations (SanPin 2.3.2.1324-03). For example, pate minced meat, cakes, etc. For such goods, expiration dates are not extended, because their safety may be lost due to deterioration and accumulation of toxic substances;

Short-term. They have a shelf life of 0.5 to 30 days: bakery, confectionery, tomatoes, berries, etc. These products do not lose safety, but when long-term storage lose quality;

Long-term storage. Their expiration dates range from a month to a year (the processes of deterioration in their quality are slow, but safety may be lost. Therefore, their expiration dates are limited.

Long-term storage goods can be without time limits. They can be stored for years (flour, pasta, canned food, frozen meat, fish.

Storage conditions and shelf life of food products are specified in the standards, in the "storage" section.

5.1.3 Food packaging

Package- this is a means or a set of means that ensure the protection of products from damage and loss, the environment - from pollution, as well as ensuring the process of product circulation. At the same time, the circulation process is understood as the transportation, storage and sale of products.

All packaging materials are divided into 4 large categories: consumer, transport, industrial and preservative.

Consumer packaging - always sold with the product and never separately. Such packaging is included in the price of the goods and after the sale becomes entirely the property of the consumer.

Transport packaging is different from consumer packaging. It must be durable - prevent damage, leakage and other undesirable changes in products. Such packaging must be harmless to the end consumer. Types of transport packaging: carton boxes, glass jars, colored polymer films.

Production and preservation packaging is used mainly in industry and in production.

The packaging must have the following properties:

Protective;

consumer;

The protective properties must ensure the safety of the product from the moment of packaging until the moment of consumption. They provide for the protection of the product from mechanical, physical, chemical, climatic, biological influences and prevent changes in the product beyond the established standards.

Consumer properties of packaging characterize:

Variety of shapes and sizes of packaging;

The degree of readiness of the product for consumption;

Ease of handling the packaged product;

Convenience of consumption;

Possibility of transfer of packing;

The presence of devices that prevent unauthorized opening of the package and control the contents;

Simplicity and reliability of capping and sealing. The presence of certain environmental properties of packaging

necessary to ensure minimal environmental pollution from used packaging, as well as the most efficient and cost-effective disposal of its waste.

informative;

Degree of attracting the attention of the buyer;

The level of incentive to make a purchase.

The most important requirements for packaging are also:

Optimal cost;

Maximum performance of marketing and production and trade functions;

Compliance with the dimensions of the packed goods;

Ease of automated handling, loading and unloading;

Possibility of multi-tiered stacking;

Ability to resist changes in external factors and conditions;

Versatility, i.e. possibility for packaging other types of products;

Compliance with standards (stowage in transport, packaging, transportation and storage);

Environmental friendliness (safety for human health and life, as well as environment).

Packaging classification

By appointment:

- for consumer goods;

- for industrial goods;

By the number of packed units of goods:

- individual (portioned) - to place a unit of goods;

- group - for the same goods placed in one package;

- multiple (complete) - for different goods placed in one package;

By frequency of use:

– single use (one-time);

– multiple use (reusable or returnable);

Functionally:

- consumer;

– transport;

- production;

By nature of use:

– universal;

- specialized;

- special;

In accordance with the requirements of regulatory and technical documentation:

– standard;

- non-standard;

According to the materials used:

– homogeneous - paper, cardboard, wood, glass, polymer, ceramic, metal;

- combined (from multilayer dissimilar materials - laminates);

According to the degree of exchange with the environment:

- non-hermetic;

- hermetic (no exchange between the contents of the container and the environment);

– isothermal (the set temperature is kept inside for the set time);

According to the degree of permeability:

– light, fat, gas, steam and moisture permeable;

– light, fat, gas, steam and moisture resistant;

Packaging- a technological process that consists in preparing products for transportation, storage, sale and consumption using packaging.

Packaging materials include: wrapping paper, packet and greaseproof paper (parchment, glassine), impregnated paper (waxed, bactericidal) and coated paper (tetra paper)

Tetra-brik-aseptic package consists of one layer of paper, a layer of foil and four layers of polyethylene: outer, between paper and foil, and two inner ones. Such containers are traditional for packaging dairy products, juices and drinks.

Doypack package - stand-up bags. Yogurt, mayonnaise, ketchup are packed in such containers. Advantages:

Ease of use of the contents of the package

Less space is required when transporting and storing empty bags

A doypack bag can also replace a tin can if a multilayer laminated film of heat-resistant polymers is used to form it. It can go through the process of sterilization in an autoclave along with the contents.

5.2 Requirements for the quality of raw materials. Methods for quality control of products during storage

5.2.1 Quality: concept. Consumer properties, food quality indicators.

The quality of goods is one of the fundamental characteristics that have a decisive influence on the creation of consumer preferences and the formation of competitiveness. The quality of food products is understood as a set of properties that reflect the ability of the product to provide organoleptic characteristics, the body's need for nutrients, its safety for health, reliability during manufacture and storage. The main properties of food products, which determine their usefulness and ability to meet human nutritional needs, are nutritional value, physical and taste properties and its persistence.

Nutritional value is a complex property that characterizes the fullness useful properties product, i.e. energy, biological, physiological, organoleptic value, digestibility, good quality.

The energy value of foods is determined by their content of fats, proteins, carbohydrates.

Biological value is characterized by the presence of biologically active substances in products: essential amino acids, vitamins, macro- and microelements, essential polyunsaturated fatty acids. These components are not synthesized by the enzyme systems of the body and therefore cannot be replaced by other nutrients. They are called essential and must be ingested with food (meat, fish, dairy products, etc.).

The physiological value is determined by the ability of food products to influence the digestive, nervous, cardiovascular systems of a person and the resistance of his body to diseases. For example, tea, coffee, spices, lactic acid and other products have a physiological value.

The organoleptic value of food products is determined by quality indicators: appearance, texture, smell, taste, composition, degree of freshness. They increase appetite and better assimilate food products that are optimal in appearance: usually fresh or slightly stored fruits, dietary eggs, live fish, bakery products from high-quality raw materials, as they contain more biologically active substances. The taste and aroma of foodstuffs are of such great importance that in some cases processing methods (for example, smoking of fish and sausages) are used to achieve them, even causing a slight decrease in the digestibility of protein substances. Worse absorbed products that have a dull color, irregular shape, uneven surface and excessively soft or rough texture; containing less biologically active substances; with low nutritional value. Products with defects appearance and consistency often contain substances harmful to the human body.

The digestibility of food products is expressed by the digestibility coefficient, which shows what part of the product as a whole is used by the body. Digestibility depends on the appearance, texture, taste of the product, the quality and quantity of nutrients contained in it, as well as on age, human well-being, nutritional conditions, habits, tastes and other factors. With a mixed diet, the digestibility of proteins is 84.5%, fats - 94, carbohydrates - 95.6%.

The good quality of food products is characterized by organoleptic and chemical indicators (color, taste, smell, texture, appearance, chemical composition), the absence of toxins (poisonous substances), pathogenic microbes (Salmonella, botulinum, etc.), harmful compounds (mercury, lead), seeds of poisonous plants and impurities (metal, glass, etc.). According to good quality, food products are divided into classes: goods suitable for their intended use (to be sold without any restrictions); goods conditionally suitable for their intended use (non-standard goods or marriage with removable defects); dangerous goods that are unsuitable for their intended use (not subject to sale and must be destroyed or disposed of in compliance with certain rules).

Goods suitable for their intended use can be competitive in the market and give their manufacturers confidence in the success of their activities. During the transition period, many Russian enterprises still cannot establish the production of competitive products, and the main reasons for this situation are the low level of technical equipment of enterprises, insufficient professional training employees, financial difficulties associated with a rigid taxation system, etc.

Physical properties are taken into account when assessing the quality of goods, determining the terms and conditions of storage.

Physical properties include shape, size, mass, color, transparency, density, viscosity, strength, etc.

The taste properties of food products are made up of the sensation of taste and olfactory sensations - smells. There are four types of taste: sweet (sugar), salty (salt), sour (vinegar), bitter (glycoside alkaloids). Smell - sensations perceived by the olfactory organs. The smell is an important indicator in determining the quality of wines and drinks, where the aroma manifests itself in the form of a bouquet of sensations.

Persistence - the property of a product to maintain consumer qualities for a certain period of time (subject to certain conditions) established by a standard or other normative document.

Depending on the persistence, all food products are divided into perishable (meat, fish, milk, etc.); suitable for long-term storage (flour, cereals

5.2.2. Methods for determining the quality of goods

Depending on the means of analysis and measurement, quality indicators are determined by organoleptic, instrumental (laboratory), as well as expert, measuring, registration, calculation or sociological methods.

The organoleptic method is a method for determining product quality indicators based on the analysis of the perceptions of the sense organs - sight, smell, hearing, touch, taste. The accuracy and reliability of such an assessment depends on the qualifications, skills and abilities of the employee, as well as on the conditions for conducting the analysis. Advantages of the organoleptic method: cheap, fast, affordable, and the disadvantage is subjectivity (inaccuracy).

Vision (visual sensations) plays an important role in determining the quality of food products. First, they inspect the goods from the outside and check the accompanying documents. When evaluating a product, first determine the appearance, shape, color, gloss, transparency and other properties. Appearance characterizes the overall visual impression of the product, and color - the impression caused by the reflected light beams of visible light. After that, the smell, texture are determined and, finally, the taste (juiciness, crumbling, deliciousness) is evaluated. The color (color) of the product is determined by standards (roasted coffee), by a color scale (tea) or by special recipes (wine).

With the help of smell, such properties of the goods as smell, aroma, bouquet are determined. The smell is determined by the excitation of the olfactory receptors located in the uppermost part of the nasal cavity.

For a better perception of the smell, conditions are created that promote the evaporation of odorous substances, for example, increase the surface or increase the temperature of the product. So, the smell of vegetable oil is determined after rubbing it on the back of the hand, and the smell of flour and cereals - after warming them in the palm of your breath; the smell of flour is established, and after some infusion of it in warm water. When determining the smell of products with a dense texture (meat, fish), a “needle test” or “knife test” is used. In this case, a wooden needle or a heated knife is inserted deep into those parts of the product that are most susceptible to spoilage, and after extraction, the smell is quickly determined.

Tactile (tactile) sensations determine the consistency, temperature, features of the physical structure of the product, the degree of grinding and some other properties. The consistency is checked by touching the product with a hand, lightly probing the product with the index and thumb, as well as applying efforts - by pressing, pressing, piercing, cutting (minced meat, jelly, meat, jam), smearing (pate, jam, jam), chewing (crunching cabbage , cucumbers, crackers), tapping frozen goods.

Taste and taste sensations have highest value when evaluating the quality of goods. There are four main flavors: bitter, sweet, sour and salty. They form complex tastes - sweet and sour (the taste of fruits and berries), sour and salty ( pickled vegetables), bittersweet (chocolate). Taste sensations can be different: the taste is astringent, pungent, tart, caustic, refreshing, burning, oily, mealy.

Taste and taste sensations depend on the temperature of their determination. Sweet taste is better manifested at a temperature of 37 "C, salty - at 18, and bitter - at 10 ° C. At a temperature of 0 ° C, taste sensations sharply weaken or disappear. Therefore, it is recommended to determine the taste of the product at a temperature of 20-40 ° C.

Sound and auditory sensations are used in assessing the maturity of watermelons, in determining the saturation of champagne and carbonated drinks with carbon dioxide, and in some other cases.

The scoring method of assessment is the designation of quality indicators using a conditional scoring system. It is usually used to express quality indicators determined organoleptically. In our country, 10-, 20- and 100-point systems have been adopted. Their essence lies in the fact that the most important qualitative features are evaluated by a certain number of points, depending on their significance. If there are defects in the goods, a corresponding discount of points is made. The results of the scoring are summarized. Depending on the total amount points (including taste and smell) the commercial grade of the product is established. The most important indicators are the taste and smell of the product, which allocate from 40 to 50% of all points.

Instrumental (laboratory) methods are necessary to identify chemical composition, harmlessness, nutritional value of food products, physical, chemical, physico-chemical, biochemical, microbiological methods research. The advantage of laboratory methods is the accuracy of the results.

An expert method is a method for determining product quality indicators based on a decision made by experts. The expert group includes highly qualified specialists in the evaluated products - scientists, designers, designers, technologists, as well as merchandisers and other trade workers.

The measuring method is used to determine quality indicators using various instruments, equipment, chemicals and utensils. This method requires a specially equipped room and people trained to carry out the analysis.

5.2.3 Food grades: quality and size

Marriage- a product with identified removable or unrecoverable non-conformities for one or a set of indicators

standard item is a product that matches established requirements for all selected parameters.

non-standard goods- this is a product that does not meet the established requirements for one or more indicators, but this discrepancy is not critical.

Waste- this is a kind of marriage, i.e. goods with unrecoverable significant or critical defects.

Product range is a collection of varieties belonging to the same product.

natural assortment- this is a set of varieties of products of the same name, differing in characteristic anatomical and morphological features.

Commodity assortment- this is a set of commercial varieties that differ in the values ​​​​of regulated regulatory documentation quality indicators

regrading- this is one of the most common ways of high-quality falsification.

5.2.4 Food hygiene requirements

		Hygiene requirements
		to food
	indicators of food and			Safety performance
	biological value				security
1.Nutritional value:		1. Natural food ingredients,
The amount of proteins;		harmful effects:
The amount of fat;		Ordinary Components in Extraordinary
The amount of carbohydrates;		high quantities;
The amount of vitamins;		Antialimentary components;
The amount of minerals;		Unusual components from new
The energy value;		sources of raw materials;
Organoleptic properties;		Components with a pronounced pharmaco-
Bioavailability		logical activity;
		toxic ingredients.
2.Biological value:
The degree of conformity of amino acids-		2. Substances from the environment,
of the protein composition of the product consumed		having a harmful effect
to the body's needs in amino acids;		(contaminants):
		Chemical (anthropogenic);
food (phytocompounds)		Biological (natural).
1.Nutritional value:		3. Substances specially introduced
The amount of proteins;		for technological reasons:
		Nutritional supplements;
		Technological additives;
		Biologically active additives.

essence hygiene requirements presented to food products, is reduced to their ability to satisfy the physiological needs of a person

1) in organoleptics, proteins, fats, carbohydrates, vitamins, mineral elements, energy (nutrition value);

2) essential amino acids and minor components of food
(biological value);

3) be safe for human health in terms of the content of potentially hazardous chemical, radioactive, biological substances and their compounds, microorganisms and other biological organisms (safety).

5.2.5 Food safety

Food safety - the absence of toxic, carcinogenic, mutagenic or other adverse effects of products on the human body when consumed in generally accepted quantities.

Toxicity is the ability of substances to harm a living organism.

MPC (maximum permissible concentration) - the legally established maximum permissible quantities of harmful (alien) substances in the atmosphere, water, food from the point of view of human health in terms of their safety for human health. MPCs are those concentrations that, when exposed daily for an arbitrarily long time, cannot cause diseases or abnormalities in the state of health detected by modern methods research, in the life of present and future generations.

DSD (permissible daily intake) - the daily intake of a substance that does not negative impact on human health throughout life.

Chipboard (admissible daily intake) - a value calculated as the product of ADI by the average body weight (60 kg).

Toxic Substances

Toxic elements are the most common food contaminants. They have an important feature. Most of them refer to trace elements (trace elements), which are present in trace amounts everywhere: in underground and surface waters, rocks, soils, atmospheric air, plants and animals. With food, water and air, these substances enter the human body.

In all types of food raw materials and foodstuffs, toxic elements: lead, arsenic, cadmium, mercury. In addition to the listed elements in canned products, tin and chrome. In processed products vegetable oils and animal fats, including fish oil, along with lead, arsenic, cadmium and mercury are regulated nickel. In addition to lead, arsenic, cadmium and mercury in cow butter, rendered animal fats, fatty products based on a combination of animal and vegetable fats are normalized copper and iron.

In Russia, they are subject to mandatory control in food products 10 chemical elements- lead, arsenic, cadmium, mercury, zinc, copper, tin, chromium, nickel, iron.

Lead- one of the most common and dangerous toxicants. It is found in trace amounts almost everywhere. Source of natural lead in the biosphere - rocks. The largest share of mined lead is used to manufacture lead batteries for cars, electric vehicles and other purposes. The main sources of air pollution with lead are:

Vehicle exhaust gases (260 thousand tons);

Combustion of coal (about 30 thousand tons) and other types of fuel;

Waste of many industrial enterprises.

Lead affects mainly the hematopoietic, nervous, digestive systems and kidneys. It inhibits a number of enzymes in the bone marrow that determine heme synthesis, resulting in anemia, which is one of the long-known symptoms. chronic poisoning lead. Lead intoxication can lead to serious health problems, manifested in frequent headaches, dizziness, increased fatigue, irritability, poor sleep, muscle hypotension, and in the most severe cases, paralysis and paresis, mental retardation. MPC \u003d 0.1-10 mg / kg.

Mercury- one of the most dangerous and highly toxic elements, which has the ability to accumulate in plants and in the body of animals and humans, that is, it is a poison of cumulative action. Mercury is the only metal that is room temperature liquid, however, it can exist in various physical states and chemical forms. Mercury, having penetrated into the cell, can be included in the DNA structure, which affects the human heredity. In embryos, mercury accumulates in the same way as in the mother's body, but the content of mercury in the fetal brain may be higher. The process of mercury bioaccumulation may include the following links: planktonic organisms (eg algae) - crustaceans - fish - birds. A person can be included in such a food chain at any stage; it mainly occurs as a result of the consumption of fish. For humans, the consumption of certain types of fish and shellfish is dangerous. Fish meat is characterized by the highest concentration of mercury and its compounds. When cooking fish and meat, the concentration of mercury in them decreases. The high toxicity of mercury causes very low MPC values: 0.0003 mg/m 3 in air and 0.0005 mg/l in water.

Cadmium. In nature, cadmium does not occur in free form and does not form specific ores. It is obtained as a by-product from the refining of zinc and copper. Both metallic cadmium and its salts have a pronounced toxic effect on humans and animals. The mechanisms of cadmium toxicity are that it inhibits DNA polymerase and disrupts DNA synthesis. The ability of cadmium to disrupt the exchange of iron and calcium is known. All this can lead to a wide range of diseases: hypertension, anemia, coronary heart disease, kidney failure and others. Marked carcinogenic, mutagenic effects of cadmium. The source of cadmium contamination of food products of plant origin is the wastewater of some industrial enterprises, as well as phosphorus fertilizers. Approximately 20% of cadmium enters the human body through the lungs from the atmosphere and when smoking. One cigarette contains 1.5…2.0 µg of Cd. MAC = 0.001-0.3 mg/kg

Arsenic belongs to those trace elements, the need for which for the life of the body has not been proven. Arsenic is widely distributed in the environment. The main measures for the protection of food products from contamination by this element are: protection of atmospheric air, soil and water bodies from pollution by arsenic-containing emissions, industrial sewage and solid waste;

Tin. The main sources of food contamination with tin are tin-plated tin cans and tin foil used for food packaging. The transfer of tin from the coating to food products depends on the nature of the food product (the presence of organic acids, nitrates and oxidizing agents in it enhances the solubility of tin), the duration and temperature of storage (up to 20 ° C tin dissolves slowly), as well as the protective varnish coating. To prevent poisoning, products that dissolve tin well are recommended to be preserved in glass containers. Limit the shelf life of canned food, cover internal surfaces cans with resistant varnish and control the content of tin in canned foods

Storage is a stage in the circulation of goods, which must take place under conditions that ensure a minimum change in its quantity and quality.

The creation of stocks of consumer goods is not expedient, but it is a forced stay of finished products in the sphere of circulation. This phenomenon is due to the need for the continuity of the production process, the constant provision of the population with all the commodities required for life and the formation of reserves. The volume and assortment structure of commodity stocks are determined, on the one hand, by the volume and structure of the production of goods, and on the other hand, by the volume and structure of consumer demand. Proper planning and rationing of commodity stocks ensure uninterrupted supply of consumers, prevent the formation of excessive, excess stocks, and also contribute to the acceleration of their turnover.

Inventory may be located in factory warehouses of industrial enterprises or in areas where agricultural products are harvested; at bases and warehouses wholesale trade; in retail trade organizations and enterprises; on my way.

At the very beginning of the transition to market relations trade enterprises created maximum stocks of goods, as a result of which the deadlines for their implementation were often violated, and their turnover sharply decreased. At present, storage issues are becoming more important economic importance especially for food products. According to official data, the loss of agricultural products during their harvesting, transportation and storage ranges from 40 to 50%.

Depending on the persistence, all food products are divided into two groups:

perishable - have a high water content, their long-term storage is possible only with the use of any canning methods. In accordance with sanitary regulations especially perishable products include products that cannot be stored without cold; perishable goods include meat, fish, milk, egg products, many types of fruits and vegetables (berries, lettuce-spinach vegetables, stone fruits, etc.);

goods suitable for long-term storage - those that contain a small amount of water or have been canned: flour, cereals, pasta, sugar, dried vegetables and fruits, wines and liquors, canned food, late varieties of some fruits and vegetables, etc.

During storage, food products undergo various changes. Depending on the nature of these changes, the processes occurring during storage are divided into physical, chemical, biochemical, biological and mixed or combined.

Physical processes are processes that cause changes. physical properties product - temperature, density, color, shape, consistency, thermal conductivity, radioactivity, etc.

Chemical - these are processes that cause the transformation of individual chemicals that make up food products (caramelization of sugars, acid hydrolysis of substances), or processes that occur between individual chemically active substances that are in the product or in its atmosphere (formation of melanoidins, acetals , rancidity of fats, etc.). These processes proceed without the participation of product enzymes and microorganisms.

Some foods (dried fruits, vegetables) may undergo non-enzymatic browning (browning) - melanoidin formation resulting from the reaction between amino acids and reducing sugars. This process leads to a change not only in color, but also in the taste and smell of the product, which adversely affects its nutritional value. Melanoidins play a positive role in baking bread, frying meat and fish, contributing to the formation of a specific taste, aroma and color.

When storing canned food, as a result of the interaction of acids of canned products with the metal of the can, chemical bombardment may occur. In some cases, there is a transition of the container metal into products, which has an adverse effect on the human body when using these products. During long-term storage of food products, as a result of chemical transformations, the content of biologically active substances (vitamins, organic acids, etc.) in their composition is significantly reduced.

Biochemical processes include processes that cause the transformation of chemical constituent parts products under the influence of biological catalysts contained in them - enzymes or enzyme preparations introduced from outside. Biochemical processes are respiration, autolysis, glycolysis, etc. During these processes, complex organic substances undergo decay, and the energy contained in them is released.

Respiration is accompanied by a loss of mass of the product, the release of moisture and heat, and a change in the composition of the surrounding atmosphere. Respiration occurs in fruits, vegetables, grains, cereals, flour. With intensive breathing, foods lose a lot of sugars, acids and other nutrients. In this case, moistening and self-heating of the product (grain, vegetables, etc.) occur.

Autolysis is an enzymatic process of self-dissolution occurring in the tissues of meat and fish. As a result, its glycogen is converted into lactic acid. Under the action of autolysis, the taste, smell, tenderness and juiciness of meat improve. However, with deep autolysis, protein breakdown occurs with the appearance of an unpleasant sour taste.

Under the action of hydrolase enzymes, hydrolytic processes occur in food products. In most cases, they lead to a deterioration in the taste and smell of products and are the cause of their significant losses.

Microbiological processes are a kind of biochemical processes in food products, since a change in the quality of a product occurs due to the activity of enzymes found in microorganisms that enter the product accidentally (fermentation, rotting, molding) or are introduced artificially (the use of microorganisms in the manufacture of lactic acid products, wines, etc.). ).

Fermentation is the breakdown of nitrogen-free organic substances (carbohydrates, alcohol, lactic acid) under the action of enzymes secreted by microorganisms. During the storage of food products, alcohol, lactic acid, acetic acid, butyric fermentation, etc., can occur.

Putrefaction is a deep process of protein breakdown under the influence of rotheolytic enzymes secreted by putrefactive microorganisms. The final decomposition products are hydrogen sulfide, carbon dioxide, ammonia, methane, indole and other substances, which give the products an extremely bad smell and may cause poisoning. Most often, foods rich in protein rot - meat, fish, eggs, etc.

Mold is caused by fungi that secrete various enzymes that break down carbohydrates, proteins and fats. When moldy, products become covered with blooms of various colors, acquire bad taste and smell. Mold causes spoilage of fruits, vegetables, bread, meat, butter, eggs, etc.

Biological processes include processes caused by biological objects - rodents and food pests. These changes also have a great impact on the quality and shelf life of the products.

During the transportation and storage of products, all of the above processes do not occur in isolation from each other - they are interconnected and interdependent, so one change often entails another. In this sense, one can speak of combined processes occurring during the processing of raw materials, transportation and storage of food products.

An analysis of the processes occurring in food products leads to the conclusion that some of them are due to internal features the foods themselves, and others by the influence external environment. Food products differ from each other in chemical composition, nature and intensity of these processes.

According to the most characteristic features for storage, all food products can be divided into three main groups.

The first group is fresh food products of the animal and plant origin(whole organisms, or their organs, or individual parts) in which biochemical, physical and chemical processes occur (for example, grain, vegetables, fruits, meat, fish, etc.). Biochemical processes are especially active in them.

The second group is products derived from animal or vegetable raw materials. They are the most active chemical and physical processes and very weakly biochemical. These are bakery products, sugar and confectionery, dried fruits and vegetables, salted, smoked and boiled products.

The third group is canned products, in which, thanks to special processing and sealed packaging, biochemical processes are practically suspended, and physical and chemical processes are completely suppressed.

The fundamental differences between the three groups are that the products of the first group can be well preserved only with their constant interaction with the external environment (i.e., while maintaining a constant metabolism in their tissues), and the products of the third group - with complete isolation from the external environment. environment. Accordingly, the shelf life of products of the first group depends on their physical and chemical characteristics and environmental conditions, and the third group - on the method of processing and the degree of sealing. An intermediate position is occupied by products of the second group. The main processes occurring in the food products of this group during storage are primarily due to their physical structure and chemical composition. These processes cannot be completely avoided, but they can be significantly slowed down, which will prevent significant changes in the quality of the product even during long-term storage. Throughout the entire storage period, it is necessary to maintain the physical, chemical and biochemical processes characteristic of food products at a certain level.

Physical and physico-chemical processes occur in products under the influence of temperature, humidity, gas composition, light, and mechanical influences. These are the processes of sorption and desorption of water vapor and gases, crystallization of sugars and salts, aging of proteins and colloids, compaction of bulk substances, deformation and violation of the integrity of products.

The sorption process, i.e. absorption of moisture can take place during the storage of salt, granulated sugar, flour, biscuits, crackers, waffles, etc. In this case, the products soften or lose their flowability and cake. During desorption, the product dries out, as a result of which its mass decreases and its quality deteriorates. This process is inherent in fresh fruits and vegetables, bread, liver, etc. In some products (confectionery, jam, honey, ice cream), sugar crystallizes during storage, which leads to a deterioration in the appearance, texture and taste of the product.

The aging of proteins and colloids during storage of products explains the worse swelling of cereals, flour, legumes, and an increase in the duration of their preparation.

Mechanical damage causes deformation of confectionery, bread, pasta, fruits and vegetables, which leads to a decrease in the quality or complete unfitness of the product for consumption.

Some products have a strong odor that can be absorbed by other products. Therefore, products such as smoked meats, herring, cheeses cannot be stored together with confectionery, bread, butter, etc.

The slowdown or acceleration of various processes in goods during storage largely depends on the temperature, humidity and composition of the air, ventilation and illumination of the room, commodity neighborhood, packaging and stacking of goods, and many other factors.

Air temperature has a great influence on the development of microorganisms and pests, the activity of enzymes and the rate of chemical reactions. An increase in temperature by 10 °C accelerates enzymatic reactions by 1.3–5 times, and chemical reactions even more. Therefore, most food products are stored at low temperatures, which have a detrimental effect on many microorganisms, pests and minimize enzymatic and chemical processes. For long-term storage products, the temperature in the storage should not exceed 1 °C, and for perishable products - not more than 6 °C. For especially perishable products, the maximum shelf life at a temperature not exceeding 6 ° C is from 6 to 72 hours, depending on the type of product. These are meat, dairy, fish, vegetable products, confectionery, etc.

Approved retention periods perishable products calculated from the end technological process, cooling and include the stay of products at the manufacturing plant, transportation and storage at enterprises Catering and trade. The manufacturer must label each batch of especially perishable products, indicating the temperature and expiration date on the labels or packaging. The safety of many goods is best ensured by creating a continuous cold chain from the producer to the consumer.

Humidity during storage of goods is also of paramount importance. atmospheric air always contains water vapor. Relative humidity is the percentage of the actual amount of water vapor in the air to the amount required to completely saturate it at a given temperature and pressure. The lower the percentage of relative humidity, the less water vapor is contained in the air. Air humidity fluctuates with temperature.

Fluctuations in the relative humidity of the air cause changes in the moisture content of goods. Each type of product is characterized by a certain humidity, the deviation from which can change the direction of chemical and biochemical processes. Therefore, the humidity of the air must be maintained at such a level as to prevent both moistening of dry goods and drying out of goods with a high moisture content. To store goods with a high moisture content (fruits, vegetables, meat) in warehouses Relative humidity should be maintained at 80-95%. Goods with low humidity (sugar, flour, salt, crackers, etc.), as well as products that can oxidize (fats) should be stored at a relative humidity of 65-75%.

The composition of the gaseous environment of the storage has a significant impact on the safety of products. In a storage room for many goods, the composition of the air should be: 78% nitrogen, 21% oxygen and 0.03% carbon dioxide. Since many products come into contact with air, it is necessary to take into account the influence of individual components of air, primarily oxygen, on them. So, packaged meat, fish and other products are better preserved in an atmosphere with a low oxygen content and a high carbon dioxide content.

Air ventilation has a positive effect on the safety of many goods. It helps to lower the temperature in the storage, remove excess moisture vapor from it, reduce the concentration of carbon dioxide, and also activates the protective functions of goods - grain, fresh fruits, vegetables, etc. Depending on the method of air supply, natural, forced and active ventilation are distinguished.

Light during storage of most products plays a negative role: it accelerates the processes of respiration, oxidation and destruction of many vitamins. Under the influence of light, discoloration and turbidity of wine, beer, juices, greening and sprouting of potatoes and vegetables, oxidation of fats, rancidity of cereals and flour can occur. Therefore, many goods are stored in darkened rooms.

Containers and packaging materials also affect the safety of food products. Packaging protects the goods from external influences, high or low temperatures, air humidity, light, foreign odors, microorganisms, etc.

Goods are stacked in warehouses separately according to their names, types, types, grades and batches. Each product has its own styling features.

Refrigeration is not only the most versatile and highly effective way maintaining food quality, but also necessary condition receiving High Quality products at various ways canning (production of ham, fermented milk products, low-salted fish, etc.). The storage of many food products fresh (meat, fruits, vegetables, etc.) or frozen (meat, fish, etc.) is based on the use of cold. Chilled products are stored from 10-30 days (meat, fish) to several months (fruits, vegetables, eggs), frozen - up to a year or more. Cold suppresses, but does not completely stop, the processes that cause spoilage of the product; cooling and freezing are accompanied by the suppression of the vital activity of microorganisms and their death, but do not ensure the sterility of products.

Cooling is a process in which the temperature of the product is reduced to cryoscopic (freezing point) or 1-2 ° C below it. The cooling method is chosen depending on the type and condition of the product, the required speed of the process, and further processing technology. Apply cooling in air, in liquids, melting ice or under vacuum. in a universal way is air cooled. Meat and meat products, poultry, eggs, fruits and vegetables, butter, dairy and other products are cooled in the air. in liquids ( cold water, brine) cool fish, poultry, some vegetables, bottled drinks. Vacuum cooling is used for fruits and vegetables.

Freezing is the process of partial or complete transformation into the ice of the water contained in the product. Freezing is used to ensure the stability of the product during long-term storage (meat, fish, etc.) or to give products special taste properties (ice cream, etc.). Various mineral and organic substances are dissolved in the water contained in food products, therefore the freezing point, or cryoscopic point, of most natural food products is close to 0 ° C (for meat juice from -0.6 to -1.2 ° C ; in egg yolk -0.1 ° C; in milk - 0.94 ° C, etc.). Damage to tissue structure during freezing is the less, the lower the temperature and the more intense the process. When storing frozen foods, temperature fluctuations above 1 °C are undesirable. They enhance the process of moisture recrystallization (an increase in the size of larger ice crystals at the expense of small ones), worsen the structure of the fabric and increase the shrinkage of the product.

Storage chilled products the role of relative air humidity is especially great. For various refrigerated products, the relative humidity of the air should be 75-95%; in storage rooms for frozen products - close to 100%.

Food products can be protected from microbiological spoilage by chemical means. Currently, more than 100 such substances are known. However, most of them can adversely affect human health or significantly impair the natural properties of the product. In Russia, to protect products from spoilage, such chemicals like sulfur dioxide and sodium benzoate.

Sulfur dioxide is used mainly for harvesting fruit and berry raw materials in order to lengthen the season for its processing (sulfitation), as well as to keep the grapes fresh. Sulfur dioxide quickly evaporates from the tissues of berries (which is important for preserving nutritional properties grapes), therefore, the treatment is periodically repeated by introducing sulfur dioxide from cylinders into the storage facilities or burning sulfur (5 g of sulfur per 1 m 2 of the room). In addition, sulfur dioxide is used by placing sodium bisulfite in boxes of grapes (or other berries). Slowly decomposing during storage and reacting with the water released by the grapes, sodium bisulfite forms a small amount of sulfur dioxide, which is quite sufficient to prevent spoilage of the berries.

Sodium benzoate can only be used in food preservation.

Sorbic acid has recently become widespread in the preservation and preservation of products (for fruit and berry juices, fruit and vegetable preserves and semi-finished products). Application of this chemical drug promising for protection against spoilage of condensed milk, cheese, sausages, fish, dry and semi-dry wines, soft drinks and other products. Sorbic acid most strongly inhibits the development of yeasts and molds. However, it has little effect on the development of many bacteria, including lactic acid ones. Therefore, it can be used to prevent spoilage. sauerkraut from molds and yeasts (without suppressing the vital activity of lactic acid bacteria).

Biomycin (chlortetracycline) is an effective antibiotic. The use of ice, to which biomycin is added (5 g per 1 ton of ice), lengthens the shelf life of fresh fish by almost 2 times. The content of biomycin in the product should not exceed 0.25 mg/kg.

Ionizing radiation is widely used to preserve food products, primarily β-rays, X-rays. The most common radiurization (from radiare - to radiate, durare - to prolong) is the radiation treatment of food products at doses that suppress the vital activity of microorganisms without compromising the appearance, taste, smell, nutritional properties products, which increases their shelf life. This term was proposed by a special commission

International Agency for Peaceful Uses atomic energy(IAEA) instead of the widely used term "radiopasteurization" in order to avoid erroneous analogies with heat pasteurization.

Microorganisms that cause food spoilage vary considerably in their resistance to ionizing radiation. Botulinus spores are especially resistant, during the development of which a toxin is formed that can cause severe poisoning. They die only at doses of about 5 krad. Spores of mold fungi are much less resistant, many of which lose their vital activity at doses of 200-500 krad. The viability of different yeasts decreases 10 times at doses of 25-250 krad.

They react differently to radiation and food products. Threshold doses have been established, above which the color and taste of the product change: for fresh fruits and vegetables from 40 (lettuce) to 900 krad (cherries); for fruit and vegetable products from 70 (lemon juice) to 500 krad (dried prunes); for fresh fish from 500 (fresh carp) to 1800 krad (perch); for meat from 300 (mutton) to 2100 krad (bacon); for dairy products (milk, cheese) about 70 krad.

Radurization can significantly extend the shelf life of many food products and, in some cases, replace refrigeration storage. Experimental shipments from Australia and New Zealand to England of half-carcasses of mutton and quarters of beef carcasses irradiated at a dose of 0.4 krad showed that they can be transported no worse than frozen meat. According to the Institute of Biochemistry. A.N. Bach, short-term irradiation of potatoes and vegetables completely eliminates their germination, so that they can be stored in conventional storage facilities at a relatively high temperature. The results of studies conducted in the USA, Canada, France, Russia and other countries indicate that all tested products, irradiated with the recommended doses, did not contain harmful substances. In the United States, it is allowed to eat irradiated grains and grain products, potatoes, oranges, bacon, fish fillets from cod, flounder, and sea bass.

The Ministry of Health of the Russian Federation is allowed to use radiurization of small-sized fruits and vegetables, the shelf life of which is determined by weeks, days and largely depends on the degree of contamination with microorganisms. Here, the extension of storage periods even for several days can have importance. For example, strawberries can be stored for 4-5 days in cold storage, and 10-12 days with additional irradiation. It is possible to extend the shelf life of irradiated sweet cherries, red tomatoes, etc. by 2 times.

The method of controlled gaseous environment is increasingly used for long-term and high-quality storage of fresh fruits and vegetables. This method is based on maintaining a certain gas composition of air (oxygen, carbon dioxide and nitrogen), depending on the characteristics of the product. Carbon dioxide and oxygen affect the quality of products and pathogens of their spoilage in different ways. Thus, the storage of meat, fish and other products in a controlled gas environment is based on the use of the antiseptic properties of carbon dioxide. To do this, the content of carbon dioxide in the environment must exceed 20%.

Fresh fruits and vegetables cannot withstand such high concentrations of carbon dioxide. Serious metabolic disorders occur in their tissues, and the quality of fruit and vegetable products is rapidly deteriorating. Therefore, the storage of fruits and vegetables in a controlled environment is not based on the suppression of the vital activity of phytopathogenic microorganisms, but on maintaining the metabolism of substances in the tissues of fruits and vegetables at a level that ensures their slower ripening and better preservation of their inherent resistance to functional and infectious diseases.

In a gaseous environment, fruits are mainly stored. The combination of low temperature with a certain gas composition eliminates the disadvantages inherent in storing fruits in conventional refrigerators. Depending on the type and variety of fruits, a different gas composition is used: nitrogen 79-97%, oxygen 2-16%, carbon dioxide 0-10%. The unequal response of individual fetuses to gas mode due to the different permeability of gases into fruits, depending on the thickness and chemical composition of the skin, the internal volume of gases, the chemical composition cell sap.

The gaseous medium for storing fruits is of two types: o normal gas mixtures, in which the total content of oxygen and carbon dioxide is the same as in air, i.e. 21%; O subnormal gas mixtures in which the total concentration of oxygen and carbon dioxide is below 21% (CO 2; 0 2; N 2 - 5; 2; 93 or 0; 3; 97 - subnormal mixtures; 10; 10; 80 or 5-10 ; 11 - 16; 74-79 - normal mixtures).

The use of a controlled gas environment makes it possible to increase the storage temperature of many varieties of fruit and vegetable products by 1–2 °C and extend the shelf life by 1–3 or even 4 months.

Storehouses with a controlled gas environment are refrigerators with sealed chambers with a capacity of 50 to 200 tons of fruits. To automatically maintain the level of the gas composition and register it in storage facilities, electronic gas analyzers are installed, as well as a system of temperature control devices, etc.

Natural decline- commodity losses due to natural processes that cause a decrease in the number of goods.

Storage method- set technological operations, ensuring the preservation of goods by creating and maintaining the specified climatic and sanitary and hygienic regimes, as well as methods for their placement and processing.

Attrition rates — size limit product losses, established by a regulatory document for a specific type of product.

Good neighborhood rule- the requirement for the joint content of goods with the same storage regime, as well as with sorption properties acceptable to each other; based on the principle of compatibility of different products that do not have mutual harmful effects.

Storage mode- a set of climatic and sanitary-hygienic requirements that ensure the preservation of goods.

Tara- packaging, which is a product for the placement and spatial movement of products. The container is consumer, industrial and transport.

Consumer packaging- containers that come to the consumer with products and do not perform the function of a transport container.

Shipping container- a container that forms an independent transport unit.

Package- a means or a set of means that ensure the protection of products from damage and loss, and the environment - from pollution.

Storage conditions- a set of external environmental influences due to the mode of storage and placement of goods in warehouses.

Storage- the stage of the technological cycle of product distribution from the release of finished products to consumption or disposal, the purpose of which is to ensure the safety of the original properties or their change with minimal losses.