Perishable food is found commonly within refrigerators inside houses and buildings. Within the game, perishable foods will slowly turn stale, and then become rotten. However a food's lifespan can be extended with a working refrigerator as refrigeration extends the foods life twice as long. A good plan for long-term survival is to eat perishable foods before non-perishable foods, as their speed of rot will accelerate after the power goes out.
However, even if left refrigerated with the power on, perishable foods will eventually become rotten and dangerous to eat, but with a high cooking level, some rotten food can be used in crafting recipes for recovering their usages.
Rotted perishable food restores under 1/2 of the hunger value of a fresh item but will make a character sick consuming it, even if cooked. Foods such as Steak, Salmon and Eggs are also dangerous to eat raw, and can lead to sickness. These types of foods must be cooked first before being consumed to avoid illness.