Water activity

Microorganisms need free water for growth. The water activity (AW) is a measure for the amount of water which not is bound e.g. to salts and thus available for the microorganisms. The water activity of a sample has a great influence on its stability.

Most bacteria need a water activity above 0.75 for survival and growth. Most moulds cannot grow at a water activity below 0.65. DB Lab has equipment for determination of the water activity in small samples.