FSHN 101 Lecture Notes - Lecture 27: Shelf Life, Psychrophile, Chemical Reaction

• School: University of Illinois
• Department: Food Science and Human Nutrition
• Course: FSHN 101
• Professor: Bohn Dawn

Document Summary

Provides cool storage of foods at temperatures ranging from 28f to 60. To be out of the (cid:862)da(cid:374)ger zo(cid:374)e(cid:863) food te(cid:373)perature (cid:374)eeds to be <40f . Water in the foods is not frozen: consequently, the shelf life of perishable products is extended only for a few days or weeks. Growth of nearly all pathogenic (ugly) microorganisms is prevented: however, some spoilage (bad) microorganisms (psychrophiles) may thrive. Freezing: provides cold storage of foods as temperatures lower than 28f. Growth of all microorganisms is prevented and some are destroyed. Contain four essential mechanical components: evaporator. Heat from the food changes liquid refrigerant into gaseous refrigerant: compressor. The temperature and pressure of the gaseous refrigerant is increased: condenser. Gaseous refrigerant condenses back into a liquid when the heat in the refrigerant is released from the back of the refrigerator: expansion valve. Shelf life increases (2-5 fold for every second: undesirable effects. Example: raw meats, raw poultry, raw fish.