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[Insight] Water Activity to Determine The shelf Life of Food

Very often, if appropriate control is not carried out in advance, part of the water contained in food and pharma products is subject to the development of bacteria and mold. These microorganisms can determine the shelf life of food or drugs over time and therefore expiration, creating potential health risks for consumers. This fundamental parameter is called aW, water activity.

Water activity (aW) is the amount of “free” or “available” water in a product compared to “bound” water, the value is ranging from 0 to 1.0. Pure water have activity value 1.0. 

But what does this free water mean?

In fact, water exist in a material as the free water and the bound water. Free water is physically and weakly bounded, for example by the surface bonding, while the bound water is chemically and strongly bounded to the material. This means, the free water can be used by the microorganism to live in the food/pharma products.

That is why, water activity could provide the detail information on microbial growth, the chemical and biochemical stability of the product and  most importantly the shelf life.

While total water content does not provide all those information. 


Our Steroglass’ WATERLAB is completed with the Dew Point Sensor, offers you a fast (less than 5 minutes), direct and accurate analysis of your samples’ water activity.

Feel free to contact us!