BIOLOGY 2EE3 Lecture Notes - Lecture 12: Food Spoilage, Wood-Decay Fungus, Proteolysis
4 Dec 2017
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Document Summary
Biological structures such as rinds or shells. Some food spoilage is desirable: changes to milk to form cheese, yogurt, butter, etc, raw milk has a neutral ph, contains the nutrients lactose, fat, protein, minerals, and naturally harbors microbes such as lactic acid bacteria. Refrigerated, pasteurized milk: begins with reduced microbial load from heat processing, and storage at cold temp increases generation time. Salted butter: low water activity, a solid structure to reduce microbial mobility, low ph. Cheese: lower water activity (salt, little water), and its solid structure reduces microbial motility. Yogurt: has a ph < 4. 4, which is inhibitory to many contaminating microbes. Techniques are used to minimize food spoilage: multiple methods used to prevent food spoilage. Increase acidity: reduction of water activity of food, control of temperature, addition of chemical preservatives, use of modified atmosphere packaging (map, hurdle technology.
