Food can be altered by different environmental factors such as temperature, humidity, time, etc. All types of food contain microorganisms on their surface that, generally, at room temperature can multiply progressively, affecting their qualities.
Heat and cold are opposite physical properties, but they are used to ensure that food is in optimal condition for consumption. If we subject a food to high sources of heat, that is, we cook it, we make it fit for consumption. However, if it cannot be consumed immediately, it is best to subject it to cold processes to preserve its properties for longer and prevent the proliferation of microorganisms. Both affect food. heat speeds up the metabolism and cold slows it down.
The most important thing is a good chain of conservation, that is, from the original production (vegetables, fish, meats ...), to the refrigerated transport and to the point of sale. For example, vegetables after being cut can lose up to 15% of vitamin C if they are not frozen or consumed fresh.
Heat and food
Heat has a ripening effect on food. When it is done in a controlled way, by cooking them, this product can be transformed into a food suitable for human consumption. However, if it is not controlled, the heat favors the growth of bacteria and fungi, thus rendering it useless for consumption.
The only way we have to guarantee that some products are acts for consumption is by subjecting them to high temperatures long enough:
• Fish and shellfish can contain anisakis larvae that cannot withstand temperatures above 60º.
• Raw meat can transmit toxoplasmosis or contain contaminating microorganisms.
• Unpasteurized milk can contain listeria bacteria -very dangerous during pregnancy-, salmonella, Escherichia coli or C
• The consumption of raw egg is not recommended in large quantities because it affects the absorption of vitamins by the body.
However, vegetables are foods that generally, if consumed raw, after washing or sanitizing them, do not cause problems.
Cold and food
Keeping food in the old window "chiller" or modern refrigerator prevents it from spoiling. In fact, the action of cold prolongs the life of the cells and tissues that make up food.
The cold can help to refrigerate food, that is, if we are going to consume it in a short period of time, it is placed in a low temperature area so that it retains its properties and slows down the appearance of microbes, fungi or bacteria that may break them down. The refrigerator temperature for the refrigerated area must be between 0 and 5ºC.
However, when these foods are not going to be used for a long period of time, the best system is freezing. Thus, these microorganisms are subjected to temperatures in which they cannot develop, below 0º, although in order for them to remain unchanged for more than several weeks, they must be frozen below 18º C. With these temperatures, the food can remain in a freezer up to 5 - 12 months without its quality being affected. It is advisable to follow the directions on the food product label.
Freezing has a minimal effect on the quality of nutrients and is one of the best preservation methods, avoiding the growth of microbes, toxins or natural degradation processes.
Food Freezing Considerations:
• Freezing does not disinfect. It only sleeps microbes, although anisakis is rendered ineffective by freezing fish and shellfish.
• The freezers must be at least - 20ºC.
• Freezers should not have a lot of space between food.
• Use special bags and plastic containers, to avoid altering food by improper freezing.
• Food placed in the freezer must not be hot.
• Food that has been frozen and thawed should never be re-frozen.
• It is convenient to freeze the food in portion containers.
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