Course:FNH200/Lessons/Lesson 07/Page 07.4
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7.4 Summary of Lesson 7
- Low temperature processing and its packaging materials are designed to extend the food's shelf life by slowing down microbial growth and chemical/enzymatic reactions.
- Microbial growth and chemical/enzymatic reactions will resume once the food is thawed or exposed to "warmer" temperatures.
- Refrigeration (cool storage) refers to temperatures between -2°C to16°C . In particular at 4°C. This provides only a short term shelf-life extension in food as psychrotrophic organisms can still grow.
- During refrigeration, the temperature, humidity and gas atmosphere composition must be monitored in order to prevent undesirable changes in the food.
- Modified atmosphere packaging (MAP) is commonly used with some refrigerated products to enhance the shelf life of the product.
- Below -9.5°C, there is no significant growth of spoilage or pathogenic organisms
- Freezing refers to temperatures below the freezing point of water. In the food industry, a minimum of -18°C is required. Food is preserved by the use of lower temperatures and lower water activity.
- During freezing, several factors (e.g. freezing rate, final storage temperature, etc) must be controlled in order to prevent undesirable changes (oxidation reactions, freezer burn, ice crystal damage, etc)
- Packaging materials should assist in preventing these undesirable changes.
Supplemental Videos:
Reference
Potter, N. N. and J.H. Hotchkiss. 1998. Cold Preservation and Processing. Chapter 9 in Food Science, 5th ed. Chapman and Hall, New York, NY.
Authorship:
FNH 200 Course content on this wiki page and associated lesson pages was originally authored by Drs. Brent Skura, Andrea Liceaga, and Eunice Li-Chan. Ongoing edits and updates are contributed by past and current instructors including Drs. Andrea Liceaga, Azita Madadi-Noei, Nooshin Alizadeh-Pasdar, and Judy Chan.
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