Secondary flora of Casar de Cáceres cheese: Characterization of Micrococcaceae

Abstract

We have identified 190 Micrococcaceae isolates made during the ripening of Casar de Caceres cheese, a semisolid cheese made from raw ewe's milk. The identification revealed that only 7 isolates (3.7%) belonged to micrococci and 183 (96.3%) to staphylococci. Among the staphylococci, only 7, isolated in the early stages of ripening, were coagulase positive. One was identified as Staphylococcus intermedius and the remaining 6 as S. aureus. The coagulase-negative staphylococci included among the most abundant species were: 115 isolates identified as S. xylosus, 36 isolates as S. caseolyticus though certain characteristics differed from the original description of the species and 10 isolates as S. saprophyticus. Some other isolates were identified as the following species of staphylococci: 4 as S. cohnii subsp. urealyticus, 1 as S. cohnii subsp. cohnii, 3 as S. lentus, 3 as S. sciuri, 2 as S. gallinarum, 1 as S. capitis subsp. capitis and 1 as S. caprae. The lipolytic activity of many S. xylosus isolates and the caseolytic activity of the S. caseolyticus isolates make them feasible candidates to be used with starters to improve the flavour of pasteurized-milk cheeses.