Microorganisms、too embarrassed to ask others about！（Part 8）

Microorganisms grow in frozen food?
All activities of living organisms, including microorganisms, are carried out through liquid water. Therefore, microorganisms cannot multiply when completely frozen. That is why ice cream has no expiration date. The same is true for the mammoths in the permafrost of Siberia, which are preserved in a state that does not allow them to decay.
The growth of microorganisms is indeed suppressed in the frozen state. However, microorganisms do not die even in the frozen state. Even if they are frozen to a crisp, they will begin to thrive once they are brought back to room temperature. In other words, temperature is necessary for the growth of microorganisms, but not necessarily for their survival.

Can microorganisms live in a vacuum?
Air is not always necessary for microbial survival. Lyophilization is often used to preserve microorganisms for long periods of time. Microorganisms can be stably preserved for long periods of time by freezing the microorganisms with an appropriate cell protectant such as monosodium glutamate and then allowing the water to sublimate. Of course, the microorganisms cannot grow in this state, but they can be preserved for a long period of time.
Although not exactly a vacuum, there are many microorganisms that thrive in the absence of air. These are called anaerobic bacteria. Some well-known examples are Bacillus botulinum, Bacillus tetanus, and Bifidobacterium bifidum. Many so-called lactic acid bacteria also survive in the absence of oxygen. A great number of microorganisms live in the intestines of humans and animals, but most of them are said to be anaerobic bacteria.