Wikipedia describes Water activity as an element amount used to symbolize the energy status of the water in a system. It is determent as the vapor pressure of water above a sample divided by that of pure water at the same temperature, consequently, pure distilled water has a water activity of exactly one. It is extensively used in food science as a easy, clear-cut measure of the dryness of food, foods characteristically have an optimum water activity at which they have the greatest shelf life. Water activity is also used in the pharmaceutical production and chemicals for moisture sensitive products.

Pet food production is one of the fasted growing industries worldwide valued at $91  billion  dollars  in  2018  Gone  are  the  days  of  feeding  your  pet  scraps  from the table; pet food today is carefully formulated to provide healthy diets, avoid allergies, and provide variety.

Since water activity testing is critical to ensure quality and safety of manufactured products, it is common to find water activity instruments in most quality assurance laboratories. As with any laboratory test method, good laboratory practices require routine verification assessments for water activity to make sure the instrumentation is working properly. This can be accomplished by running tests on standards of known value and comparing the test results to the actual values. While this can be difficult for some common quality assurance tests that do not have independent standards, such as moisture content, water activity standards exist in the form of electrolytic (salt) solutions. These water activity standards are one of the most important tools available to laboratory personnel to provide them with confidence in their water activity testing results and facilitate troubleshooting.