Abstract

Dairy production in the Peruvian Andes is mainly based on small herds. However, there is little information on how hygiene affects milk quality during the rainy season. The study's objective was to evaluate the hygienic factors of milk and milking practices during the rainy season in small herds located at two high Andean altitudinal levels. The characteristics of the factors related to the milking process were recorded using an observation guide, and 108 raw milk samples were collected from 18 herds with Brown Swiss cows at two altitude levels. Samples were obtained from the milk collection containers and milk. The results showed that 56.5% of the samples analyzed were unhygienic, with no significant differences in bacterial counts between altitudinal levels. However, a strong correlation was identified between precipitation and the presence of coliforms (0.726) and mesophilic aerobes (0.861). Factors such as milking location, hand washing, and use of cleaning agents were associated with microbial contamination, acquiring odds ratios (OR) of 4.04, 5.26, and 4.71, respectively, during the months of heavy rain. The study concludes that the hygienic quality of milk in small high Andean herds significantly deteriorates during the rainy season, with counts of total coliform bacteria and mesophilic aerobes exceeding recommended levels, particularly during peak rainfalls. This finding highlights a direct relationship between the intensity of rainfall and the quality of milk, underscoring the need for improved milking practices in the rainy season to ensure the safety of the products.