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  • Water Activity (Aw)

    Measure of the free water or available water inside a food matrix. This is an important technical factor in food, as it influences the types and ability of microorganisms that might develop in a food product. The effectiveness of HPP as a microbial inactivation step depends greatly on the water activity levels: very dry foods or foods with Aw values below 0.87 are a more difficult target for HPP, due to the reduced efficacy of isostatic pressure in inactivating microbes in such low water availability conditions.