Pasteurized milk: efficiency of pasteurization and its microbiological conditions in Brazil

This study aimed to verify the pasteurization efficiency and the microbiological quality of milk sold in the city of Rio de Janeiro, Brazil. The microbial quality of pasteurized milk samples was assessed by sample testing for the presence of Salmonella spp., coliforms at 35 degrees C, coliforms at 45 degrees C, and mesophilic bacterial counts. In addition, the pasteurization efficiency was verified through tests of neutral phosphatase and peroxidase enzymes. Salmonella spp. were not detected in any (100%) of the analyzed samples. However, 85 (70.8%) and 69 (57.5%) of the samples were noncompliant with current legal standards for coliforms at 35 degrees C and 45 degrees C, respectively. As for the aerobic mesophilic bacteria, 48 (40.0%) of the samples were noncompliant. From the 120 samples of pasteurized milk studied, 100% were negative for neutral phosphatase, whereas 12 (10.0%) were negative for peroxidase. Logistic regression indicated the absence of relationship between present lactoperoxidase and all the microbiological parameters studied, which suggested that the quality of pasteurized milk was associated with factors related to steps before or after heat treatment.