Storage temperature and microbiological quality of bulk raw milk in Rio Pomba, Minas Gerais

Abstract

The refrigeration of raw milk in bulk tanks represents an obstacle in the milk production chain associated with the selection of spoilage psychrotrophic bacteria with negative consequences for the industry. The aim of this work was to evaluate the temperature and microbiological quality of raw milk stored in 15 refrigeration tanks in the city of Rio Pomba, Minas Gerais, in the seasons, between October 2016 and July 2017. The temperature of the milk in each tank was determined at the time of sample collection. Subsequently, counts of aerobic mesophilic, psychrotrophic, pro teolytic psychrotrophic, lipolytic psychrotrophic, lecithinase-producing psychrotrophic and Pseudomonas sp. were determined. There was no difference (p > 0.05) in milk temperature at the time of collection among the 15 bulk tanks, however, the temperature averages were above 4.0 ºC, therefore in disagreement with Normative Instruction n.º 76. The aerobic mesophilic count varied between 3.4 and 6.8 Log CFU/mL, and 42% of the samples did not comply with the legal standard. The count of psychrotrophic microorganisms presented variation between 3.0 and 8.1 Log CFU/mL with mean equal (p > 0.05) to the count of aerobic mesophilic microorganisms. More than 50% of the samples presented counts of Pseudomonas sp. above 4.0 log CFU/mL. It was concluded that the hygienic-sanitary conditions in the production of raw milk in the city of Rio Pomba, MG, were inadequate, thus highlighting the importance of contamination prevention of raw milk through the implementation of Good Practices in productive chain.

Keywords

• leite cru refrigerado
• microbiota deterioradora
• qualidade