what is the promble for heat, cold microorganisms
cocci
It's to kill microorganisms to prevent the spread of germs.
It is in their genetic makeup. Often the more complex microorganisms will be more heat resistant compared to the lower forms.
Used to spread microorganisms on an agar plate
food can be carriers of microorganisms. remember that food can serve as a good culture medium for these microorganisms to thrive. that is why to prevent such spread of foodborne diseases it is really important to wash the food thoroughly and to cook them properly.
You certainly can use heat to kill microorganisms in a "protein-rich" solution if you don't care whether the proteins get denatured or not.
Infection
Microorganisms which spread diseases are harmful microorganisms.
Moist heat coagulates microbial proteins (including protein enzymes), inactivating them irreversibly.
Kills microorganisms in the water, preventing the spread of disease.
Yes, they help food stay fresh longer. Antimicrobial products kill or slow the spread of microorganisms. Microorganisms include bacteria, viruses, protozoans, and fungi such as mold and mildew.