Main microbial flora present as natural starters in Cebreiro raw cow's-milk cheese (northwest Spain)

Abstract

Thirty samples of Cebreiro, a fresh or short-time-ripened raw cow's-milk cheese produced in Northwest Spain, were analyzed for the presence of aerobic mesophilic bacteria, (AMC) lactic acid bacteria (LAB), enterococci and Micrococcaceae. Mean AMC and LAB counts exceeding 10(9)/g were higher than those reported for other fresh or short-time-ripened cheeses, although Micrococcaceae occurred in lower numbers (< 10(5)/g) than reported for other raw-milk cheeses. Out of a total of 126 LAB representation isolates, 59 were identified as enterococci (38 as Enterococcus faecalis) 30 as lactococci (24 as Lactococcus lactis subsp. lactis), 25 as leuconostocs (14 as Leuconostoc mesenteroides) and 6 were identified as mesophylic lactobacilli. The enterocci in general were more proteolytic and produced more diacetyl/acetoin than the other LAB groups lactic acid bacteria isolated. It seems that a starter for making Cebreiro cheese should contain these microorganisms so as to reproduce the typical characteristics of traditional raw milk Cebreiro cheeses.