NU FS100 Lecture Notes - Lecture 4: Cold Food Festival, Campylobacter Jejuni, Refrigerant
16 Mar 2018
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Document Summary
The use of low temperatures can extend the shelf-life of foods: cool storage: 16 to -2 c, refrigeration (0 - 5 c) not killing micro-organism, just slowing their growth. Fridges remove heat from inside and release it outside refrigerator (4. 5 c. 7 c) (cid:8213) when liquid evaporates it absorbs heat (cid:8213) when vapor condenses it releases heat (cid:8213) refrigerant: liquid that evaporates inside refrigerator to create cold temp. Psychrophilic bacteria can grow in fridges (l. monocytogenes, c. jejuni, Works best when foods are cooled right after slaughter or harvest (cid:8213) to allow rapid heat removal: hydrocooling, vacuum cooling. Refrigerated storage requires control of t, air circulation and humidity (80% to 95%) Energy requirements depend of: insulation, frequency of door opening, quantity of products, respiration rate. Modi ed gas atmosphere and hypobaric chambers reduce o2 availability. Effects: minimal effect on taste, texture and nutritional value (ex: vit.
