Since refrigerators have been around, we have lost a lot of trouble with storing food. But even in the refrigerator or freezer, food is not always safe. Certain species of mold or microbes can also develop at low temperatures. How to store food so that the products are longer tasty, appetizing and do not lose their value?
Food deteriorates under the influence of ubiquitous microorganisms, such as bacteria and fungi. Some products are particularly unstable due to the content of easily rotting proteins or quickly rancid fats. The main ingredient - water - has the greatest impact on the deterioration of the quality of food products. The more water there is, the faster the chemical reactions take place and the faster the microbes grow. Therefore, many methods of food preservation (drying, smoking, s alting,freezing ) primarily reduce the water content. It removes it or changes the state of aggregation, preventing the growth of bacteria and mold. The durability of the products can also be extended by lowering the temperature and limiting the access of atmospheric oxygen and light.
Storing food in the refrigerator
Forfood storage fridgeis irreplaceable. It used to be coldest under the freezer. Now the refrigerator and freezer compartments are usually separated. You must read the instructions to know which shelf to store fish and meat (temperature must be lowest) or cheese (moderate). But even in the refrigerator, food is not completely safe. Although bacteria multiply the fastest at a temperature of 7 to 60 degrees C, it is common on fruits and vegetablesYersiniawithstands minus 2 degrees C. Similarly,Listeria , which is cold-resistant and can cause food poisoning when stored in the refrigerator for a long time. Both bacteria can be present in, for example, cottage cheese, while others are often found in poultry. How to protect yourself from them? Without extending the recommended storage period and observing hygiene. So let's wash the fruit. Keep the curd for a short time. We insulate poultry from the rest of the products by wrapping them in foil and making sure that the juice does not drip. It is also worth remembering that even in a freezer, at a temperature of minus 12 degrees C, certain species of harmful mold can develop.
You must do itHomemade freezing
Temperature in industrial cold storesis minus 20-30 degrees C, but minus 18 degrees C in a home freezer is enough to ensure safety. The meat to be frozen must be absolutely fresh. It should not be washed or crushed. Designed for longer storage, it must be frozen to a temperature of minus 10-18 degrees C and it must be kept constantly. At home, it is worth freezing berries. First overnight - loose in a single layer on a tray, then pour them into airtight plastic bags. They will be fresh for up to several months, as long as they are kept at a constant and as low temperature as possible.
Vegetables should not always be refrigerated
The cold of the fridge - paradoxically - accelerates the spoilage of tomatoes, cucumbers and peppers. They get stains when taken out of it. If we buy frosted tomatoes (from the cold store) in the supermarket, we should eat them right away. They are firm, but the cooling temperature destroys their resistance to mold and bacterial diseases. The optimal temperature for tomatoes is the same as in the cellar, i.e. 10-13 degrees C, for cucumbers - not lower than 7 degrees C. If we have a choice of either a room temperature of 20 degrees C or 6 degrees C in the fridge, choose rather 20 degrees C, especially for 2-3 days. Cucumbers and tomatoes will have a much better flavor, and tomatoes that are not fully red will ripen quietly (but not in the sun, because they will be too warm). All root vegetables, potatoes and longer-lasting fruits, such as apples, can be stored in the cupboard for a few days. Potatoes can be stored well in the cellar temperature, that is 10 degrees Celsius, and if we cannot provide such temperature, potatoes have to be bought on a regular basis. In the refrigerator they will start to decompose starch into simple sugars and they will become sweet, and in a heated cellar - they will sprout. The cold is tolerated well by lettuces and root vegetables - beets, carrots, parsley, radishes - even 0 ° C (but not below). Citrus fruits are not afraid of cold either, because they are protected by a thick peel, but they will also withstand room temperature, but dry faster in it. Perishable berries (strawberries, blueberries, raspberries, blackberries, wild strawberries, blueberries) are better to be stored in the refrigerator, but not longer than a few days (raspberries and wild strawberries up to two days). Tomatoes (and apples, melons and peppers) should not be stored with lettuce and cucumbers, which turn yellow faster in this company. This is due to the ethylene released by tomatoes, which is used in ripening rooms.
Safe storage of frozen food
After purchase, each frozen food should be put in a thermo-insulating bag and moved to the home freezer as soon as possible. Remember that the taken out frozen food is much more perishable than the fresh product. It never issterile - although the low temperature inhibits the growth of microorganisms, it only kills them in 70%. The rest of the bacteria are just waiting for favorable conditions to start multiplying immediately. The juice that leaks when thawing is an excellent medium for them. Defrosting, freezing and thawing - this is a recipe for producing a microbiological mine. That is why we only buy frozen, loose and stone-hard food. Collapsing always indicates storage at different temperatures - e.g. once it was minus 30, then minus 20 degrees C. Such temperature changes are against the rules. Then the water, despite freezing, slightly melts or evaporates. If we feel that the contents of the bag are softening under our fingers, we should not put it in the freezer, but use it.
ImportantRead labels
- Pay particular attention to the storage conditions of minimally processed, not chemically preserved food specified by the producers. If we read that something "should be eaten by … (date here)" and next to "store at a temperature of 0 to 2 or 4 degrees C", then the shelf life only applies to the given temperature, not higher.
- Liquid products in cartons are thermally fixed (pasteurized) and aseptically poured, i.e. sterile and microbiologically safe.
- The manufacturer guarantees that he will keep the best features of the product until the given date (usually with a safety margin). Read how much time can be kept after opening; even hours are important, because then the product loses sterility and microorganisms develop in it.
- The expiry date of the canned goods refers to a closed can. After opening, you get oxygen and the contents must be eaten within 2 days. Store it in the refrigerator after moving it from the can to the vessel - because the contact of oxygen with metal has a negative effect (when opening it, the metal insulating coating is destroyed).
Storing food without oxygen
Food is usually protected against air - due to oxygen, which accelerates chemical changes and thus spoilage of food. So it's worth buying vacuum-packed products. You can also use special containers at home equipped with an air-sucking pump. There are also food products industrially packed in the so-called a modified atmosphere, i.e. with a reduced level of oxygen and an increased level of carbon dioxide. We will recognize such products by the sealed foil. Colored products, even pre-packed, are damaged by light, because the carotenoids contained in them degrade faster under the influence of light. That is why, for example, carrot juice in a bottle, it is better not to keep it on top, but put it in the cupboard. Before air access and drying wellsecures the so-called food wrap. On the other hand, aluminum foil is used for baking and additionally protects against light. Also suitable for packing food for travel. It is worth knowing that it is inadvisable to use it with acidic products, because aluminum reacts with acids. As for the containers - not all are suitable for all products. Meat, cold cuts, cheese and butter should not be placed in plastic containers that contain substances that dissolve in fat. We should make sure that the product is certified by the National Institute of Hygiene, and the manufacturer guarantees safe storage of food with fat.
Storing green vegetables
But the lack of oxygen is not always a good thing. It can even be dangerous when it comes to green vegetables. By storing, for example, spinach under anaerobic conditions, we accelerate its spoilage. The respiratory processes taking place in the tissues increase the temperature, and the lack of air access may result in the production of very harmful nitrites in vegetables. Lettuce in particular needs oxygen to prevent it from starting to breathe anaerobically. We make a mistake when we pack it in a plastic bag so that it does not dry out and remains brittle. Firstly, lettuce will lose its taste, and secondly, and more importantly, the nitrates it contains, which are not themselves toxins, will start to reduce to harmful nitrites without oxygen. Some plant species (including chives, parsley, radishes, dill) tend to accumulate nitrates because they need nitrogen to make protein. Nitrates are also accumulated by root vegetables, such as e.g. carrots and beets, which are the most beetroots. These products must be sprinkled with water to prevent them from drying out and losing their firmness, and store them in an open or perforated bag or wrapped in paper.
How to store:
Meat, processed meat and poultry
Raw meat should not be washed before putting it in the fridge, because then we increase the amount of water that will be readily used by microorganisms (that's why the meat is packed in trays with a water-absorbing lining. It is best to cool the meat quickly to a temperature of 0-2 degrees C. If you want to extend the storage time, you can sprinkle it with lemon juice, because the acid slows down the growth of microorganisms.
Fish
Must be kept on ice, i.e. at a temperature of minus 1-2 degrees C. But we do not have such conditions at home, so in fact, the fish should be prepared after bringing it from the store, or the day after cleaning and washing. Unless we buy frozen - thenit must be put in the freezer immediately. If it's skinny, it will last much longer than fat, up to three months. Smoked fish can be kept at a higher temperature, but always in cling film - so that the smell does not spread to other dishes.
Dairy products
Breaks down quickly under the influence of microorganisms. When shopping, check the use-by date. The lower the storage temperature (above zero), the better. Yellow cheeses stay fresh for several days. It's best to wrap them in food paper. Before serving, they should be removed from the refrigerator to give them flexibility and flavor at room temperature. The curd cheeses are unstable. The expiry date stated on the package is usually 48 hours. It may be longer if you buy cottage cheese in foil packaging hermetically sealed by the manufacturer. Eggs can be stored in the refrigerator for 2-3 weeks. It is important not to wash them beforehand (the natural coating on the shell is a barrier to bacteria), and always scald them before use, because on average one in 1000 eggs is contaminated with Salmonella. UHT milk and milk drinks in sealed cartons have a relatively long shelf life. After opening, they can be eaten without boiling for a maximum of 12 hours. Yoghurts and kefirs must be refrigerated according to the date specified by the manufacturer - no longer!
Fats
Chemical and enzymatic reactions take place during their storage, which causes them to become rancid. The storage time depends on the temperature, light, atmospheric oxygen and the type of packaging (the best dark glass). Vegetable oils are not an attraction for microorganisms because they do not contain water. Refined are produced with the addition of substances protecting against oxidation. They can be kept for up to a year without a refrigerator, preferably with limited light. More valuable cold-pressed oils are less durable and should be refrigerated at 4-6 degrees C (up to 3 months). In the oil, under the influence of low temperature, lumps may form, but it is okay. Butter is the most difficult because it can become moldy. We keep them in the refrigerator and we keep an eye on the use-by date! The butter will be stored the longest when clarified by our grandmothers' method: after boiling and cooling down, remove the layer of "scum" and pour out the water. Lard at 6-8 degrees C can be stored for several months.
Cereal products
Bread is best eaten during the day. It becomes stale the fastest, changing the taste, smell and texture at a temperature close to zero, therefore it is not stored in the refrigerator. It quickly becomes moldy in foil. On the other hand, freezing bread inhibits the processes of spoilage andenables storage for several months without fear of losing its taste. Flour preparations are also frosted - dumplings, dumplings, dumplings, cakes, pizzas.
Silage
We keep it at a temperature below 10 degrees C. They must always be covered with juice to prevent air from entering them, which causes the growth of mold and putrefying bacteria.
Ready meals
They will last 2-4 days at a temperature below 10 degrees C, the longest - acidic dishes, because the acid reduces the growth of microorganisms. That is why some dishes should be acidified by adding tomato paste. Main rule: cool quickly. Do not keep on the stove, especially on a ceramic plate, which is slowly cooling down - because then microorganisms that are not indifferent to he alth or toxic, e.g.Clostridium perfingens , which can cause food poisoning, multiply.