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Chapter 3 : Natural Microbial Ecosystems and Their Progression in Fresh Foods
Category: Food Microbiology; Applied and Industrial Microbiology
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The microbial ecosystem of fresh foods is not as complex as that of the corresponding preharvest products, and this is due in large part to the removal of many microbes from meats by animal carcass washing in which hot water, steam, and/or organic acids are applied. Assuming that fresh foods are harvested, processed, packaged, and stored according to acceptable procedures, the fate of each group of microbes can be predicted if one knows how the foods are packaged along with the time and temperature of storage. While some fresh foods are inhibited by specific toxic products of others, some are inhibited by as-yet-unknown means, and this is discussed further in a section on nonspecific microbial interference. When fresh foods that contain a typical microbiota undergo refrigerator spoilage, some or all of the microbial growth parameters come into play. A number of studies on the fate of S. aureus in chicken pot pies, in macaroni and cheese dinners, and in laboratory culture media were published by researchers at the Campbell Soup Co. in the 1960s. Overall, this research demonstrated the inability of this pathogen to compete with naturally occurring organisms under various conditions. The microbial ecosystem of fresh foods is composed of a large number of bacterial genera and species, with most consisting of Gammaproteobacteria and Firmicutes. Whatever the mechanism of microbial interference, both the direct and demonstrated mechanisms, along with the less well-defined mechanisms, interact to affect microbial progression in fresh foods.
The most common genera of bacteria found in foods, beverages, and food processing environments
Commonly reported genera of yeasts and molds in most fresh, preserved, and fermented foods a
Predominant microbial groups on intact lamb carcasses held at 5°C in air a
Demonstrated and suggested mechanisms of microbial interference in foods