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Government regulations recommend water activity measurements in food

FDA, USDA, USP, AOAC, ICH, ISO, Eudralex – regulatory bodies around the globe require the use of water activity. We've compiled a complete regulation reference list. 

Water activity is an important property. It predicts stability with respect to microbial growth, rates of deteriorative reaction, and physical properties. The U.S. Food and Drug Administration has incorporated water activity into safety regulations. These regulations detail specific requirements and practices to assure that products are produced under sanitary conditions and are pure, wholesome, and safe. Use the table below as a reference to U.S. government safety regulations that recommend the use of water activity.

Table 1. Thirteen government safety regulations for food, pharma, and cosmetics
Agency Product Type Reference No.  Last Update Description
FDA Food FSMA Sec. 103 12-5-16 Describes preventative actions and risk based approach to safety, identifies the need to monitor preventative controls but does not mention water activity specifically
FDA Food 21 CFR part 117 12-5-16 Outlines the practice for Hazard Analysis and Risk-Based preventative controls, including monitoring practices for testing such as water activity (does not specifically mention water activity)
FDA Food 2013 Food Code 2017 Food code acts as a guide for determining hazards and preventative controls as part of new FSMA regulations. The definition of potentially hazardous foods, as found under "Time/Temperature Control for Safety Food" in the 2017 food code is based on aw and pH and uses Interaction Tables A and B
FDA Food 21 CFR part 113 5-1-16 Thermally processed foods are described as being unsusceptible to bacterial growth if under 0.85, older code that is superseded by information in the 2013 food code
FDA Food 21 CFR part 110.8 4-4-15 GMP's outlined in this section under manufacturing operations (2) indicate that GMP's can be verified by monitoring water activity of the product to make sure it stays at safe levels
USDA RTE meat Generic HACCP Model 10 2-5-05 Identifies water activity as the appropriate way to monitor the drying process, specifically in place of moisture-protein ration
USDA RTE meat Compliance Guidline for Jerky (Including small plants) 5-27-14 Identifies the need to verify water activity to demonstrate the product meets the critical control point, and it recommends aw lower than 0.70 to control mold but also references the 0.85 level
USDA RTE meat Compliance Guidline for Control of Listeria 1-2014 Discusses options for making sure products are free of listeria including a post lethality treatment that prevents growth (water activity can be used for this purpose, but it doesn't specifically mention it)
USP Pharma USP 1112 2006 Provides justification for reduced microbial testing if low water activity (below 0.60)
USP Pharma USP 51 5-51-16 Method for Microbiological Testing now mentions that the testing refers to only those product with a water activity higher than 0.60 and references USP 1112
ICH Pharma Q6A Decision Tree 6 and 8 Oct 1999 References whether the product is inherently dry such that it will not support microbial growth, then provide scientific evidence of such and microbial limits testing may not be necessary
ISO Cosmetics ISO 2961 6-1-2010 Guidelines for the risk assessment and identification of microbiologically low risk products–many references to water activity
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