Like all organisms, microorganisms rely on available water in food for growth. They take up water by moving it across the cell membrane. This water movement mechanism depends on a water activity gradient – on water moving from a high water activity environment outside the cell to a lower water activity environment within the cell. […]
Water activity is an important property. It predicts stability with respect to microbial growth, rates of deteriorative reaction, and physical properties. Thus, worldwide food safety agency 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 […]
WATER ACTIVITY (aw) is derived from fundamental principles of thermodynamics and physical chemistry. As a thermodynamic principle there are requirements in defining water activity that must be met. These requirements are: pure water (aw = 1.0) is the standard state, the system is in equilibrium, and the temperature is defined. In the equilibrium state μ = […]
