Refrigerating or freezing food, even if the temperature is extremely cold, cannot kill microorganisms. Temperatures approaching 0°C and lower delay the growth and the metabolism of microorganisms. In fact, prepared frozen food (a temperature of -32°C is used to avoid the formation of ice crystals) is increasingly popular. However, as soon as the food is defrosted, the microorganisms start to grow again, which is why it is highly recommended to never refreeze food which has been previously frozen and then thawed out.
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