Influence of educational level of dairy farmers, suitability of facilities, and milk production profile on bacterial contamination of milk and milking environment

Abstract

The objective of this study was to verify whether there is an association between bacterial contamination of milk with their milking practices and the socioeconomic profile of milkers. Fourteen farms were studied, which were characterized in terms of workers' socioeconomic backgrounds and microbiological profiles of the main contamination sites during the milking. Results were compared statistically. Aerobic mesophiles (AM), total coliforms (TC), and coagulase positive staphylococci (CPS) were enumerated, and Salmonella spp. was surveyed in water, hands, teats, equipment, utensils, and milk (from the cooling tank). The average age of farmers was 47 years old, 24 of which were dedicated to dairy farming. Only one farm had an outsourced workforce. Of all farmers, 93% performed two milkings a day through a mechanical bucket milking system, using piped well-water. In the milking parlors, there were sinks and/or faucets, floor, ceiling, and electric lighting. Before milking, milkers had their hands washed, discarded the first three milk jets, washed the cows' udders, and dried them with disposable tissue paper, but did not perform pre- and/or post-dipping. Raw milk was refrigerated in all evaluated farms immediately after milking, mostly in an expansion tank. Average contamination by AM was 3.19 log CFU/cm² or mL and by TC of 0.77 log CFU/cm² or mL. CPS was not detected in water, but in the other samples, the average count was 0.75 log CFU/cm² or mL. Salmonella spp. was not detected in the samples obtained in the evaluated farms. There were significant differences among farms, and raw milk contamination was influenced by farmers' schooling level, performance or not of good practices, conditions of the facilities, and production volume.