Lactic acid bacteria isolated from a hand-made blue cheese

Nearly 500 strains isolated from different media used to study the aerobic mesophilic and lactic acid flora of Valdeon cheese (a Spanish hand-made blu e cheese) have been identified. Nearly 95% of aerobic mesophiles were lacti c acid bacteria (LAB). From these, Enterococcus (40.4%) and Lactococcus (42 .2%) were the dominant genera, with Lactobacillus (4.1%) and Leuconostoc (5 .0%) being also found. The selectivity of the other media used was variable and this is discussed. Several species of Enterococcus were isolated from our samples (Ent. avium, Ent. faecium and Ent. durans), although one was ou tstanding (Ent. faecalis, 24.7% of the total of strains identified). The do minating LAB species found was Lact. lactis subsp, lactis (31.1%) Other LAB identified were Lact, raffinolactis, Lb. plantarum, Lb. casei, Leuc. mesen teroides subsp dextranicum, Leuc. mesenteroides subsp. mesenteroides and Le uc. paramesenteroides. The evolution of the lactic-acid flora found during the manufacture and ripening of this variety of cheese showed a pattern mar ked by the dominance of lactococci and enterococci during the first stages and the substitution of lactococci by lactobacilli and leuconostoc from dry ing onwards which would be, along with enterococci; the major genera found, in the cheese at the stage of consumption. From a technological point of vi ew, the quantitative importance of certain species such as Lact. lactis and Ent. faecalis, as well as the presence of others, ie. Lb. plantarum and Le uc. mesenteroides, suggest their possible use as starters in the industrial manufacture of this variety. (C) 2000 Academic Press.