摘要：A relation between a method of production and treatment of milk and the incidence of E. coli being used as the indicator organism of hygienic quality of milk was studied. E. coli was tested in 0.001 mL of milk; when hand milking was applied, it was found in 6.81% of samples, when machine milking was used, it amounted to 88.6%. It was suggested that the improper maintenance of milking machines enabled the implantation of E. coli and contamination of milk with this organism. During milk storage in cans a lesser number of samples was E. coli positive (19.81%) than in milk kept in basins where the incidence of E. coli averaged to 43.36% and amounted up to 94.42% in relation to the total number of tested samples. Since the incidence of contaminated samples in some regions was significantly lower (11.86%), however, it is suggested that the consience of people during milk treatment plays a significant role in regard to the total number of E. coli. Of the milk samples taken at the dairy gate, 61.28% contained E. coli. Increased milk contamination with E. coli from the stable to dairy showed the accumulation of negative effects to milk and its possible dependance on the irregular methods applied in milk production. A low percentage of E. coli contaminated samples (34.53%) was established in the periods when milk producers were given more intensive instructions in regard to the adequate procedures to be applied in milk treatment. When the number of E. coli was compared during various seasons of the year and in different geographical regions (hilly versus plain regions), no proof could be found suggesting a significant effect of these factors to the isolation of E. coli and hygienic quality of milk. A study of E. coli thermoresistency showed that 7.0% of strains survived the pasteurization process suggesting a dependance of the results obtained in pasteurized milk upon a contamination level in raw milk.
