Food storage requirements and precautions

Food storage requirements and precautions

Requirements and precautions of food storage, food preservation is something that everyone needs to do, so that we can eat fresh food, and different foods actually have different skills. Let's take a look at the food storage requirements and precautions.

Food storage requirements and precautions 1 Choose fresh food and pay attention to food hygiene.

Buying food is a process of choice and decision. We should be cautious enough, choose and calculate carefully, have a healthy concept, choose nutritious food, and make more informed decisions according to personal preferences and economic conditions.

Fresh food refers to foods that have been produced or processed recently and have a short storage time, such as grains, vegetables and fruits that have not been harvested soon, livestock and poultry that have been slaughtered recently or freshly cooked meals. Choosing fresh food is the first step to pay attention to food hygiene from the source, and learning to distinguish and buy fresh and hygienic food is the key to ensure food hygiene.

I like local seasonal food.

Choosing local seasonal food can ensure the freshness and nutrition of food to the maximum extent. Food needs a certain distance from the place of production or processing to the point of sale, which will increase the storage time on the way.

If the storage and transportation distance is long and takes a long time, it will lead to the loss of water in food and increase the metabolic time of food itself. At the same time, corrupt microorganisms will grow and multiply in large numbers, leading to the degradation or decomposition of nutrients in food, the freshness of food will be reduced, and the sensory quality will become worse. In severe cases, the fermentation of spoilage microorganisms will also lead to food spoilage. Therefore, choosing local and seasonal foods to ensure freshness and hygiene is also an important measure of energy saving, low carbon and environmental protection.

Learn to tell the freshness of food.

Prepackaged foods can know the freshness of food by looking at the production date on the food label; When the date of production and other information can not be obtained, we can distinguish whether the food is fresh or not by looking, touching and smelling, and by sensory indicators such as the appearance, color and smell of the food. Different foods have different freshness, different sensory characteristics and different identification methods. Vegetables, fruits and other plant foods are easy to identify. The methods for identifying the freshness of animal foods are as follows:

Livestock meat

The muscles of fresh meat are shiny, even red, and the fat is white (beef, mutton or light yellow). The appearance is slightly dry or slightly wet, and it does not stick to hands. After pressing the muscles with your fingers, the depression immediately recovers, and it has a normal smell of livestock meat. Tendon meat has elasticity and toughness. Observe the external state, color and dry film of meat under natural light, pay attention to the pollution of blood clots, mold and fly maggots, and determine the state of deep tissue and the viscosity of meat.

The muscles of stale meat are dull, the fat is grayish green, the appearance is extremely dry or sticky, and the depression after finger pressing cannot be recovered, leaving obvious traces, which may have a bad smell.

poultry meat

The skin and muscles of fresh poultry meat are naturally shiny, the surface is not sticky, it has a normal inherent smell, and the muscles are firm and elastic.

The meat surface of old birds is dull, the skin surface is wet or sticky, dark red, light green or gray, or has mildew spots, and the meat quality is loose. Shiatsu muscles have obvious finger marks, which may have a musty or putrid smell.

egg

The eggshell of fresh eggs is firm, complete and clean, often with a layer of powder, which makes hands feel rough and heavy. Light perspective shows that eggs are reddish.

The eggshells of stale eggs are gray-black, with spots and cracks, light and floating to the touch, opaque or grayish-brown shadows when viewed by light. Open common sticky shells or loose yellow. "Bad" eggs are produced because there are many small holes in the eggshell, which are similar to sweat holes in human skin. The eggshell surface often carries microorganisms such as bacteria and molds. When the temperature of the external environment changes sharply and there is water condensation or mechanical damage on the eggshell, these microorganisms will enter the egg through the small holes in the eggshell. Protein is decomposed by microorganisms and enzymes in eggs.

Eggs with shells: The decomposition of protein's frenulum leads to the displacement of yolk, forming "eggs with shells";

Scattered yellow eggs: the yolk membrane decomposes and the yolk is scattered to form "scattered yellow eggs";

Muddy soup eggs: The continuous reproduction of microorganisms leads to the mixing of yolk and egg white, forming "muddy soup eggs";

Rotten Eggs: protein is further decomposed by microorganisms, forming putrid substances such as hydrogen sulfide, amines, fecal odor, indole, etc., giving off a foul smell and forming "rotten eggs". There are many harmful substances in "rotten eggs", which will cause poisoning and endanger human health after eating.

Pay attention to health knowledge

◆ Buying eggs depends on the label time, and eggs within a week are the best.

◆ Eggs should be refrigerated at 2~5℃, preferably within 20 days. A day at room temperature is equivalent to a week in the refrigerator. It should be preserved naturally in early winter and eaten within 15 days as far as possible.

◆ Cold storage of eggs can prevent salmonella pollution and hinder the aging process of egg ingredients.

In a frost-free refrigerator, eggs are not easy to go bad, but are more likely to dry.

◆ The yolk of fresh eggs is shaped, with more yolk, more crude protein and less dilute protein.

fish

The surface of fresh fish is shiny, the scales are intact and not easy to fall off, the eyeball is full and prominent, the cornea is transparent and clear, the gills are bright red, the mucus is transparent, the muscles are firm and elastic, the depression disappears immediately after finger pressing, the abdomen is normal, and the anal orifice is white. The skin color of stale fish turns yellow or red, the eyeball is flat or slightly sunken, the cornea is cloudy, the gill filaments are adhered, the muscles are slack, the elasticity is poor, the abdomen is swollen, the anal orifice is slightly prominent, and there is a bad smell.

milk

Fresh milk is milky white or light yellow, uniform liquid, without precipitation, clots and mechanical impurities, viscous, with unique milk flavor and no peculiar smell.

Stale milk is pale pink or obviously yellow-green, or dark in color, in the form of thick and uneven solution, which is condensed into dense clots or flocs by milk and has obvious smell. If the liquid milk stored at room temperature expands, there will be a risk of deterioration, so it is recommended to give up eating. Yogurt and cheese are relatively storable, but they are always in the process of fermentation, which will turn sour and deteriorate over a long time, so they need to be stored in the refrigerator.

Chita

Soybean products rich in protein are also easily contaminated by bacteria and viruses. Old tofu is dark gray, dark yellow or reddish brown, with sticky surface, unpleasant smell, rough and loose organizational structure and incomplete blocks. When touched by hand, it is fragile and inelastic.

Food should be cooked raw and cooked separately

In the whole process of food cleaning, cutting and storage, raw and cooked food should be separated. Use special utensils to handle raw food. Kitchen knives, chopping boards and containers at home should be cooked separately, including vegetable washing pots and meat washing pots to avoid possible cross-contamination.

When cooking, you should always wash your hands to avoid the pollution of eggshells and raw meat.

Store raw and cooked food in the refrigerator. They should be put in different boxes. Cooked meat, ham sausage and ready-to-eat cold dishes that can be eaten directly should be strictly separated from raw food and packaged separately.

The refrigerator stores raw and cooked food in compartments.

Food should be stored properly.

The purpose of reasonable food storage is to keep fresh and avoid pollution. The basic principles of grain and dried fruit food storage are low temperature, darkness, ventilation and dryness. The measures often taken are dust prevention, fly prevention, rat prevention, insect prevention and mildew prevention. When storing food, special attention should be paid to keeping away from toxic and harmful substances, such as pesticides, insecticides, rodenticides, disinfectants and nitrite, to prevent pollution and accidental consumption.

Animal foods are high in protein and easy to spoil, so special attention should be paid to low-temperature storage. Generally, low-temperature storage is divided into refrigeration and freezing. The refrigeration temperature of common refrigerators is 4~8℃, and the freezing temperature is -23~- 12℃.

Fresh vegetables are easy to produce nitrite if they are stored in damp and overheated places, and the content of nitrite is higher after decay, so they need to be stored at low temperature and eaten as soon as possible. However, some foods are not suitable for cold storage.

If tropical fruits (banana, litchi, pitaya, mango, etc. ) are stored in the refrigerator, and there will be frostbite; Cucumber stored in the refrigerator for more than three days, the skin will be soaked in water, losing its original flavor; Some baked goods (such as bread). ) If you put it in the refrigerator for too long, it will gradually become hard or stale, which will affect the taste and flavor of food. Therefore, the above foods should be purchased and eaten as soon as possible.

Cooked food should also be eaten as soon as possible. If it needs to be stored for more than 2 hours, especially when the temperature is high in summer and autumn, the storage temperature should be controlled above 60℃ or below 5℃ to slow down the growth of microorganisms and prevent the propagation of pathogenic bacteria, and the refrigerator should not be too full.

Cold air needs enough circulation space to ensure refrigeration effect; Don't mix raw and cooked food, put cooked food on top and raw food on the bottom; After the leftovers are put into the refrigerator, they should be eaten as soon as possible and heated repeatedly for no more than once. Check the refrigerator regularly, and take out the food immediately if there are signs of deterioration and corruption; Clean the refrigerator regularly and scrub the inner wall and every corner of the refrigerator.

Frozen food should also pay attention to food hygiene.

Most microorganisms are dormant under freezing conditions, so frozen food can be preserved/fresh for a long time. Considering that some microorganisms can survive and reproduce at low temperature, it is suggested that when storing frozen food at home, we should pay attention to the production date and shelf life to ensure that the food can be eaten as soon as possible within the shelf life. When bulk food is frozen, it can be divided into several small packages, one for each time, to avoid repeated freezing and thawing and increase food safety risks. The suitable time for meat storage in the refrigerator is shown in the following table, and the matters needing attention in the process of storing food in the refrigerator are shown in the following figure.

Matters needing attention in the process of storing food in refrigerator

When purchasing frozen and chilled foods in supermarkets/markets, you can wear disposable plastic bags to avoid direct contact with your hands; If you buy overseas frozen food online, you should also pay attention to the customs food quarantine information, sterilize the external packaging and eat or save it.

Food storage requirements and precautions II. Soy milk:

1, people with spleen deficiency who are prone to diarrhea and bloating and those with kidney deficiency should not drink soybean milk.

2, can not drink with drugs: such as tetracycline, erythromycin and so on.

3, it is not appropriate to rush into eggs: egg white will combine with trypsin in soy milk to produce substances that are not easy to absorb.

4. Don't drink too much: Excessive drinking can easily lead to indigestion, bloating, diarrhea and other discomfort.

5. Don't drink on an empty stomach: Drinking on an empty stomach will convert protein into heat in the body and be consumed, thus reducing the nourishing effect.

People eat two or five kinds of nuts.

1, pistachio: it can be said that it is a friend of the soul. It can lower blood cholesterol and reduce heart disease.

2, pumpkin seeds: eating about 50 grams of pumpkin seeds every day can effectively prevent prostatitis and prostate cancer and lower blood pressure. Patients with stomach heat should eat less.

3. Peanut: Known as "longevity fruit", it is a good diet for tuberculosis patients and tumor patients.

4, pine nuts: known as "longevity fruit", containing protein, fat, sugar, often eat can nourish and strengthen the body. People with gallbladder dysfunction should eat carefully.

5. Cashew nuts: The content of saturated fatty acids in cashews is slightly higher than that in humans. Therefore, we should avoid eating too much; Contains a variety of allergens and may have allergic reactions. Therefore, it is best not to eat more cashews for the first time.

Three or ten kinds of food should not be eaten more.

1. Pickled vegetables: containing carcinogenic substance ammonium nitrite.

2. Stinky tofu: It contains a lot of volatile alkaline ammonia and hydrogen sulfide, which is a' rotten product' decomposed by protein and is harmful to human body.

3, monosodium glutamate; The daily intake should not exceed 3 grams, too much will increase the content of sodium glutamate in blood and limit the utilization of calcium and magnesium.

4, instant noodles: regular consumption will cause malnutrition.

5, sunflower seeds: eating too much will consume choline, which will hinder the body's fat metabolism and affect the function of liver cells.

6, spinach: contains more oxalic acid, zinc and calcium in food will be combined with oxalic acid and excreted, resulting in the lack of calcium and zinc.

7, preserved eggs: regular consumption will cause lead poisoning and calcium deficiency.

8, pig liver: regular consumption will lead to arteriosclerosis.

9. Barbecue: toxic substances such as benzopyrene will be produced during the smoking and roasting process, which will induce cancer.

10. Fried dough sticks: Alum is an aluminum-containing compound, which is toxic to brain and nerve cells and even leads to Alzheimer's disease.

Fourth, tea:

1, the water temperature for making tea should not be too high: different teas need different water temperatures, such as high-grade green tea, and boiling water of 70-80℃ should be put before brewing. 2, tea should be rushed now, not overnight: drinking overnight tea is not good for health.

3. Tea should be drunk at the same time: drinking green tea in summer, drinking black tea in winter and drinking scented tea in spring and autumn is a better way to drink at the same time.

4, tea should be drunk lightly, not too strong: excessive drinking of strong tea can lead to gastrointestinal dysfunction.

5, tea should be drunk at the right time: drinking tea after meals and at noon is beneficial, drinking tea on an empty stomach is flustered, and drinking tea at night is not fragrant.

6, tea should be warm to drink, hot drinking is harmful to health.

7. Tea is not suitable for administration: when taking sedative and antitussive drugs and sedative and antitussive drugs such as Anemarrhena asphodeloides, Fritillaria, and Semen Ziziphi Spinosae, you can't take tea together, and you can't drink tea when taking ginseng, codonopsis pilosula, gentleman, Smilax glabra, clematis, iron, ephedrine and atropine.

Five or eight kinds of food that should not be kept in the refrigerator.

1, tomatoes: cold storage, easy to appear black spots or cracks; If it is stored for a long time, it will become sour and corrupt.

2. Cucumber: The suitable storage temperature of cucumber is 10~ 12℃.

3. Green pepper: The suitable storage temperature of green pepper is 7 ~ 8 ′℃. It is easy to get frostbite and deterioration when stored in the refrigerator.

4. Banana: After being stored in the refrigerator, the skin will turn black.

5, chocolate: frosting after refrigeration, easy to mold.

6. Ham: When stored at low temperature, water will freeze into ice, and the ice will agglomerate and become soft, and the meat will become stale and the quality will decrease.

7, cold salad: cold salad is placed in the refrigerator for a long time before eating, which is very unsafe and prone to diarrhea.

8. Beer: Turbidity will appear when the drying temperature is low, and the taste will be greatly reduced.

Requirements and Precautions for Food Storage Three Precautions for Food Storage in Refrigerator in Summer

1, food placement is exquisite.

Food should not be put too much, and there should be a gap between it and the refrigerator wall to facilitate air circulation; Separate raw and cooked leftovers to avoid cross-contamination. Generally, cooked food is above and raw food is below. The temperature in the cold room is high and low, so animal foods such as fish and meat should be placed on it, while fruits and vegetables should be placed below. In the freezer, cold drinks and other foods are placed on the upper floor, while frozen fish and meat are placed on the lower floor.

2. The storage time is limited.

The cold storage time of raw meat is generally 1 ~ 2 days, and that of fruits and vegetables is 3 ~ 5 days. Eggs should be refrigerated in the refrigerator for a maximum of 15 days. Wipe the dirty eggshells first, but don't wash them with water. After five days of cold storage, even if the green leafy vegetables do not change color, it is best not to eat them. In the refrigerator, it is best not to store fish for more than two months. If the meat turns yellow due to cold, it means that the fat has been oxidized, and it is best to throw it away.

Don't wash the fruits and vegetables before putting them in the refrigerator.

Generally speaking, fruits and vegetables have a layer of wax on their surfaces to prevent microbial invasion. After washing fruits and vegetables, especially after washing with detergent, the waxy layer on the surface will be destroyed, and bacteria will easily enter the interior of fruits and vegetables, leading to deterioration and rot of fruits and vegetables.

Recommended refrigeration temperature:

Fresh meat, poultry, fish and dairy products: below 5℃;

Fresh eggs and live shellfish: below 7℃;

Fresh vegetables and fruits: 5 ~ 7℃;

After unpacking the packaged food: below 5℃.

Other considerations:

Vegetables and fruits are easy to dehydrate in cold storage, and their relative humidity should be 85%~95% and 80% respectively.

Vegetables and fruits release water and carbon dioxide when breathing, so proper air circulation should be maintained during refrigeration, and holes should be punched in the sealed film package to keep them fresh;

Eggs and vegetables don't need to be cleaned before storage, because the original protective film on the eggshell surface will be destroyed after cleaning, so that microorganisms can easily enter the eggs, while vegetables are easy to get moldy after cleaning. These two kinds of food should generally be cleaned before processing;

Fresh eggs taken out of the refrigerator should be used as soon as possible, and should not be stored for a long time or refrigerated again. Because the egg will "sweat" at room temperature after being taken out, small water droplets will destroy the surface protective layer of the eggshell, making it easy for polluting microorganisms to penetrate the eggshell and enter the egg;

Raw or half-eaten fish should be frozen before processing (-20℃ for 7 days or -35℃ for 15 hours) to kill possible parasites, or confirm that the manufacturer has carried out the above treatment;

Dry food raw materials (such as rice, flour, nuts, etc. Storage at room temperature should be packed in sealed containers (or packaging bags) to prevent moisture absorption and deterioration after moisture regain.