Contribution to the study of staphylococcus contamination of cows' milk on a number of farms in Algiers: its impact on human health.

The authors describe a survey and screening programme for staphylococcus. The study covers 14 dairy farms in the Algiers region, from which 203 samples of cows' milk were taken for bacteriological testing. The survey results show that poor husbandry conditions are the main cause of staphylococcus in cows' milk. Staphylococcus was found in the milk of 30% of the cows sampled. These results were influenced by a variety of factors, in that: the contamination rate rose with the number of pregnancies, age, and volume of milk output of the cow, as well as the bedding thickness; the milk contamination rate was greater when milking occurred outside a milking parlour and when it was performed by machine; higher rates of staphylococcus infection were found in the milk of cows at the end of lactation, in red and white breeds, and in those with cylindricalteats. Identification of the bacteria found (staphylococcus) showed that coagulase- negative staphylococci were present in 67.21% of samples, whereas coagulase- positive staphylococci were present in only 32.79%. The average count for the latter was equal to 0.54 x 10(4) colony-forming units per ml of Staphylococcus aureus. Seventy percent of the milk analysed was free from staphylococci and most of the bacteria identified were not pathogenic to consumers (coagulase- negative staphylococci); nevertheless, consuming fresh milk still presents a degree of risk.