This article discusses the basic ways of water-preparation in food industry. Water-preparation plan with elements of disinfecting for production of drinking water and drinks is given. The analysis shows that water should meet definite microbiological requirements. In order to reduce its fatal influence on the health of people the clearing and preparation of water are necessary. Development of techniques and means of clearing without chemical technologies, including ozone treatment technologies, allows one to lower and to get rid of application of chemical compounds and reagents. At the moment the ozone treatment water technologies with consequent treatment on filling filters are the most rational. Ozone is the strong oxidant and disinfects water faster than chlorine in some times. With activated carbon use both the flavouring qualities and smell become better. Technology of mutual ozone processing with absorption is the most perspective for water purification and disinfection, possessives a high efficiency in comparison with attitude to pathogen microorganisms, does not lead to the formation of harmful collateral products. Therefore, the questions of development of safe technologies and means for water preparation and treatment are actual and well timed

Seventy-one percent of the earth surfaces is covered by oceans. Water therefore is an important habitat for microorganisms and the other living beings. A consistent microbial biodiversity is present in water from phototrophs to chemioorganotrophs. The complex relationships between different microorganisms and the environment are often modified by organic, chemical and physic contaminations. The input of organic material can determine pathogenic pollution. The presence of pathogens has to be monitored to eliminate serious problems for animal and human health. Water, in fact, can be a vehicle direct (drinking water) or indirect (irrigation water) for microbial pathogens | Il 71% della superficie terrestre è costituito dagli oceani. L'acqua pertanto è un importante ambiente per i microrganismi, oltre che per tutti gli altri esseri viventi. Una grande varietà di tipi microbici colonizzano l'habitat acquatico, dai fototrofi ai chemiorganotrofi. Le dinamiche che si creano fra i diversi componenti microbici e l'ambiente sono spesso alterate da contaminazioni organiche, chimiche e fisiche. L'immissione di materiale organico può anche essere fonte di inquinamento di microrganismi patogeni la cui presenza va monitorata al fine di evitare seri problemi alla salute umana e animale. L'acqua, infatti, può rappresentare un veicolo di trasferimento, sia diretto (acqua potabile), sia indiretto (acque di irrigazione), di microrganismi patogeni