Ibores goat's milk cheese: Microbiological and physicochemical changes throughout ripening

Abstract

The microflora of Ibores cheese made with raw goat's milk without any starter addition was studied throughout the ripening period. The microbial counts for total lactic acid bacteria, pre- sumptive lactococci and presumptive lactobacilli attained maxima of 9-10 log units with little or no variation throughout ripening. Leuconostocs and enterococci levels were 2-3 log units lower, also with little variation. Coliforms and staphylococci declined steadily from relatively high initial counts, the coliforms to low levels and the staphylococci disappearing completely. Moulds and yeasts were at low levels throughout ripening. Among the identified isolates, lactococci formed the prevalent group throughout ripening, followed by leuconostocs and enterococci at similar levels to each other, and then lactobacilli at low levels. The prevailing species and subspecies were Lactococcus lactis ssp. lactis, Leuconostoc mesenteroides ssp. dextranicum, Ln. mesenteroides ssp. mesenteroides, Weissella paramesenteroides, Enterococcus faecium, E. faecalis, Lactobacillus casei and Lb. plantarum. Small numbers of other species from each of the genera were also identified. The changes in certain physicochemical parameters during ripening were determined. By 60 days, the values of the pH, total solid content, and NaCl content were 5.18, 58.9% and 2.5%, respectively. The correlation of some of the physicochemical parameters with the log counts of the microbial groups was also established. Goat's milk cheese / ripening / lactic acid bacteria / identification