MICROBIOLOGICAL QUALITY OF PASTEURIZED MILK SOLD IN SUPERMARKETS IN MERIDA-VENEZUELA

The purpose of the work was to evaluate the microbiological quality of pasteurized milk and flavored UHT (ultra high temperature) milk commercialized in supermarkets in Merida city, located on the Andes mountain range, northwest of Venezuela, in July 2017. Methods: The present study is quantitative approach, descriptive type, and experimental cross-sectional design. A stratified random sampling was carried out in selected supermarkets in the Libertador municipality. The counts of mesophilic aerobic bacteria, coliforms, molds, presumptive determination of Staphylococcus aureus and Pseudomonas aeruginosa were made in specific culture media for each microbial group. The identification of the isolated bacterial strains was carried out according to that indicated by MacFaddin (2003), supplemented with API (R) systems. The average counts of the sanitary quality indicators in whole pasteurized milk indicate mesophilic aerobic bacteria 7.4x10(2) CFU/mL, total coliforms 4.9x10 CFU/mL and molds 0.5x10 CFU/mL. In pasteurized skimmed milk the average values were mesophilic aerobic bacteria 7.2x10(4) CFU/mL, total coliforms 8.1x10(2) CFU/mL, fecal coliforms 7.5x10 CFU/mL and molds 0.8x10 CFU/mL. In flavored UHT milk, only 3.8x10 CFU/mL aerobic mesophilic bacteria and 0.1x10 CFU/mL mold were detected. No presence of S. aureus or P. aeruginosa was detected in any of the milk samples analyzed. It was posible to identify from pasteurized milk, 3 Gram negative strains corresponding to Citrobacter freundii, Enterobacter spp. and Escherichia coli. Show that pasteurized whole milk and flavored UHT milk meet the microbiological quality requirements, while pasteurized skim milk is considered unacceptable for consumption.