Microbial flora of technological interest in raw ovine milk during 6°C storage

Abstract

Changes in the microbial flora of ovine milk of medium hygienic quality (initial mean total plate count 3.3 × 105 cfu/mL) were studied throughout refrigerated storage at 6°C. Total plate counts after 48 h of refrigerated storage (mean count 4.6 × 105 cfu/mL) were under the current standards in the European Union (EU) for raw ovine milk to be used for cheesemaking after heat treatment. However, after 96 h, mean total plate counts (1.6 × 107 cfu/mL) were above the standards. Lactococci were found at levels higher than Pseudomonas spp. in milk freshly drawn (54.5% and 3.5% of total plate count, respectively) and after 96 h at 6°C (47.9% and 33.9% of total plate count, respectively). Lactobacilli, enterococci, coliforms and thermodurics were found at values lower than lactococci and Pseudomonas spp., before and after refrigerated storage (≤ 0.08% of the total plate count). A significant growth (P < 0.001) was detected for mesophiles, Pseudomonas spp. and lactococci after 96 h of refrigeration at 6°C; however, thermodurics, coliforms, lactobacilli and enterococci, showed no significant increase (P > 0.05). Presumptive Escherichia coli (β‐glucuronidase‐positive) underwent a decrease throughout storage at 6°C.