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Updated: Aug 15, 2026

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays
Published on: October 1, 2013
Trends in research related to the influence of "water activity" on microorganisms in food
1Procter & Gamble Company, Winton Hill Technical Center, Cincinnati, Ohio 45224.
Abstract:
The use of humectants and drying to make foods safe and stable has been one of the underlying principles of food preservation for centuries. With the more recent discovery that the ratio of water vapor pressure to that of pure water (aw) is a useful parameter when related to microbial growth and other stabilizing factors in foods, a valuable means of predicting stability factors based on water limitation has become available. Microorganisms have been categorized with respect to their capacity to grow and produce metabolites in various conditions of limited aw. In addition, the metabolic basis for microbial inhibition has now been determined and schemes for its genetic control have been uncovered. The implications that these discoveries have in a wide variety of applications are far-reaching.
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