Extended Shelf Life of Foods

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Extended Shelf Life of Foods

Food preservation is a critical control point that influences and determines a whole range of outcomes, ranging from preservation of nutritional quality, food safety, the wholesome nature of food, texture, taste and organoleptic qualities, and consumer appeal, along with compliance to several points in the value chain that include long-term storage, long-distance transportation and marketing. The purpose of food preservation is to eliminate any possible microbiological harm to the people who eat the food, to maintain the quality of food (texture, taste, smell), and to preserve or protect the nutrition of a safe food product. The processes of food preservation can be classified into physical method, chemical method, biological method, and preservation by controlled or modified atmosphere. Physical methods are heat treatment, cold processing, dehydration, irradiation (or cold pasteurization). Chemical methods are salting, curing, smoking, and preservatives. Biological method is fermentation. The main idea of heat treatment is to kill the microorganisms in food and inactive the tissue enzymes. Heat treatments are thermisation, pasteurization, UHT (Ultra High Temperature), sterilization, and blanching. Thermisation is a method of sterilizing raw milk with heat, 57 – 65 oC for at least 15 seconds to kill the mesophilic microbes. Pasteurization is a preservation process by giving heat to food, for example milk, to reach a minimum temperature for a minimum length of time and then immediately cooling it to 4 oC. Pasteurization can be differentiated to LTLT (Long Time Low Temperature) which is heating at 62 – 65 oC for 30 minutes, and HTST (High Temperature Short Time) which is heating at 72 – 75 oC for 15 – 40 seconds. All the pasteurized products have to be chill-stored (4 oC). UHT (Ultra High Temperature) processing holds milk at 135 – 140 °C for 1 – 2 second. Sterilization is the preservation process to inactivate of all kinds of...
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