low temperature, or cold storageCanning is one of the main methods of preserving various foods for longer periods of time. Freezing reduces the ability of microorganisms to grow and, therefore, to contaminate and spoil or alter the properties of food.
7 Myths About Freezing Food That Keep Us From Saving Money
Freezing, in addition to slowing down the chemical reactions that spoil food, makes it possible to preserve and retain its nutritional properties, refrigeration And this solidify There are two main methods of cold storage.
Both are effective as long as they are done well and the food is not previously contaminated. The main difference between the two lies in the degree of temperature in which the food is preserved. But there is more.
Refrigerate, or how to slow down the activity of pathogens
what exactly does refrigeration do slow down the activity of microorganisms and enzymes (active proteins) of microorganisms. The idea is to slow down the action of the bacteria to a minimum so that the food has more time to spoil.
The main features of this method are:
- subject to food temperature between 0ºC and 8ºCThe temperature at which most pathogens are unable to multiply.
- Refrigeration does not alter foods because they retain all of their nutritional value and their organoleptic characteristics.
- time in which useful life is preserved two and twelve days, depends on the food. For example, fish is the one that lasts the shortest.
- Refrigerated foods do not remain unchanged but the occurrence of spoilage is delayed. So heRefrigeration has less effect than freezing Since microorganisms, although more slowly, can grow and change food.
- Refrigerated food can be cooked immediately.
- Almost all foods can be refrigerated without a change in taste or texture.
- Refrigeration can be applied to almost all foods.
freeze or stop bacterial action
The preservation principle of this system is similar to that of refrigeration; The lower the temperature, the further we move away from the ideal conditions in which microorganisms grow.
idea, in this case completely stop the action of bacteria, The main differences with refrigeration are:
- The temperature between meals is subject to –18ºC (the temperature of choice at home) and -25ºC: During this process the water present in the food turns into ice.
- Unlike refrigeration, with freezing, when the water freezes, the food dries out, which helps it keep better.
- The potential for food spoilage is reduced and the risk of spreading pathogenic microorganisms is also reduced because bacterial proliferation is impossible at such low temperatures.
- What is the shelf life of food preserved for? months and even years in some casesuntil the cold chain is broken.
- By freezing food, the activity of microorganisms and enzymes is not only slowed down but also stopped, which allows it to be preserved for longer than with refrigeration.
- Frozen food requires a defrosting process before it can be cooked, making the preparation process longer.
- Although almost all foods can be frozen (meat, fish, pre-cooked meals, fruits and vegetables) some are less resistant to the process, such as vegetables eaten raw such as lettuce, mushrooms, high Fatty foods such as cream and dairy, among others.
After refrigeration, freezing is one of the treatments that produces the least amount of change in food. When melted, they retain properties similar to those of the raw products used as raw materials.
But despite the benefits of freezing, Should not be used as a way to destroy bacteriaHowever molds, yeasts or parasites such as Anisakis die below -20ºC and therefore, cannot survive at refrigeration temperatures.
But other viruses and bacteria (eg listeria monocytogeneswhich can grow at -1.5ºC) can survive, remain dormant during the cold and wait for the temperature to rise to resume its metabolic functions.
Complex for effective freezing and refrigeration
The keys to effective refrigeration and freezing are the same for both forms of preservation: Pack food tightly and maintain a constant temperatureAvoiding ups and downs.
The environment in a freezer is very dry, so if food is not well preserved, water loss from the surface can cause food to burn which can affect texture, taste and colour.
On the other hand, temperature fluctuations during storage can cause undesirable changes in the food, such as ice crystals melting and refreezing to form larger crystals.
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