Food Division Chemistry

Water Activity - Testing

The regulation of water as an ingredient in foods and food products was the earliest form of food preservation.

The availability of water for microbial growth and biochemical reactions may be controlled by dehydration, freezing and the addition of solutes such as salt and sugar, thus having the potential to prolong shelf-life of a product.

Water Activity (aW) is defined as the measure of availability of liquid water and is defined as the ratio of the equilibrium pressure of the sample (P) to the equilibrium vapour pressure of pure water (Po) at the same temperature and pressure, aW = P/Po, and can have values from zero (bone dry) to one (pure water).

Equilibrium Relative Humidity (ERH) refers to the atmosphere surrounding food. ERH = 100 x aW; where the aW refers to the activity of water in solid and liquid foods.

At ILS we are fully equipped to carry out Water Activity (aW) and Equilibrium Relative Humidity (ERH) testing.

Contact ILS -  for more information and prices on water activity and pH testing and analysis.

pH - Testing

The pH of food and drinks is regualrly monitored in many areas of the food industry.

Controlling the pH in the manufacture of dairy products is important in controlling pathogens, making sweet or sour butter and yoghurt production

In the drinks industry pH is important in the taste of wine, a monitor for factory water systems and beer production.

The pH of carcasses in the meat industry is an indicator of quality for both pre and post slaughter as well as the storage of meat.

For the making of bread and batter pH is used to control the multiplication of pathogenic organisms.

In marmalades and syrups the ph of the finished products influences the length of storage for a product.

The same is also applied in the production of sauces or cold salads where by adding small amounts or organic acids to lower the pH shelf lifes are extended.

The pH of added water is monitored as fluctuations can affect the intrinsic qualities of the food product.

Contact ILS - for more information and prices.