Our study is on the impact of the water quality of milking parlor and cattle drinking on the physico-chemical and bacteriological quality of the milk. For this, milk and water samples were collected from six farms in northern Tunisia. Results of the study showed that milk physico-chemical properties were generally within intervals close to the required standards for milk but the majority of the collected milk samples can be qualified as having poor hygienic quality. The milking parlor’s cleaning water quality, based on statistical results, affected total aerobic mesophilic flora (TAMF) as well as total milk coliforms. Cows drinking water quality, based on statistical analysis, affected milk fat content. It is clear that water quality was not the only factor affecting the quality of milk. Thus, the search for sources of contamination throughout the raw milk circuit, other than the quality of drinking water and cleaning of the milking parlor, has shown that hygiene practices (preparation for milking) and type of milking constitute the major sources of milk contamination by TAMF, total coliforms (TC), fecal coliforms (FC) and Escherichia coli (EC). After all, the increase of milk bacterial load throughout the production chain on the farm is the result of successive contaminations associated with poor hygiene practices during milking.

Keywords: Milk, water, quality, hygiene, bacteriology.