Water is used in food processing for many different purposes. Water is used in direct contact with the food or food contact surfaces (as an ingredient, steam, etc) or indirectly as a processing purposes. Therefore, water quality used in a food manufacturing plant has to be pure not only with respect to product safety, but also in view of the capability of production processes (e.g. cooling, heating and cleaning).

Water has been increasingly looked at as a valuable resource and its quality (and in this respect also safety) cannot be taken as granted. Potential physical, chemical and biological hazards introduced by water shall be adequately controlled, By water treatment when entering a food plant in many cases to ensure potable (drinking) water quality where needed. Physical hazards derived from incoming water are usually controlled by filtration (if necessary), and its effectiveness can be monitored by turbidity measurements. Chemical hazards include organic compounds, many pesticides and elements like heavy metals.

Biological hazards not only include the organisms of concern, but also the con – sequences of their presence, e.g. toxin formation by some types of algae. Waterborne micro – organisms potentially causing illness include bacteria, viruses, protozoa and helminths. The resistance / susceptibility of those organisms to commonly used treatments and the way of transmission needs to be considered to ensure water quality. Most of the pathogens are introduced into the water by animal and / or human sewage and do not grow in water. However, some are environmental pathogens that can grow in water.