Changes in the microbial flora of Tenerife goats' milk cheese during ripening

Abstract

Abstract Changes in the microbial flora of Tenerife goats' cheese, manufactured from raw milk without the addition of starter cultures, were studied during ripening. Lactic acid bacteria (lactococci, leuconostocs and lactobacilli) were the dominant microorganisms throughout ripening. Lactococcus lactis ssp. lactis was the most common Lactococcus found (78.9% of isolates classified as lactococci). It reached maximum numbers in 2-day-old cheeses and decreased afterwards during ripening. Lactobacillus plantarum (56.9% of isolates classified as lactobacilli) and Lactobacillus paracasei ssp. paracasei (37.2% of isolates) were the main species of lactobacilli isolated. L. plantarum was present in high proportions in 2-day-old cheeses but decreased during ripening, whereas L. paracasei ssp. paracasei , present initially at low numbers, increased during ripening and was the predominant Lactobacillus in 60-day-old cheeses. Leuconostoc mesenteroides ssp. dextranicum (81.8% of isolates classified as leuconostocs) was the main species identified as leuconostoc and its numbers decreased throughout ripening, particularly during the last month. Enterococcus faecalis and Enterococcus faecium , micrococci, moulds and yeasts were found at significant numbers and could contribute to the ripening process. Microorganisms used as an indicator of the bacteriological quality of the cheeses (Enterobacteriaceae, coliforms and faecal coliforms) and Staphylococcus aureus decreased sharply in the interior of the cheeses throughout ripening.