Difference Between Putrefaction and Fermentation

Regarding the difference between putrefaction and fermentation, in the involvement of microorganisms in food, the production of food that is convenient and beneficial for humans is called fermentation, and the production of unfavorable and harmful food is called putrefaction.
In addition, fermented bacteria (eg, Bacillus natto, yeast) can be stored frozen, but about 20 to 30% of the yeast will die if frozen. This is because more than 70% of the yeast cells are composed of water, and the water turns into ice when frozen.
When water turns into ice, it expands in volume (maximum ice crystal formation zone), causing fatal damage such as damage to yeast cell membranes.