Characterization of lactic acid bacteria isolated from raw cows’ milk cheeses currently produced in Galicia (NW Spain)

Twenty cheeses belonging to the four Protected Designations of Origin manufactured in Galicia (NW Spain) (6 Arzúa-Ulloa, 4 Tetilla, 6 Cebreiro and 4 San Simón da Costa) were selected from a total of 60 cheeses on basis of their (typical) sensorial profiles. A total of 218 lactic acid bacteria (LAB) isolates were obtained from the predominant microflora of the selected cheeses and were identified as Lactococci (98 isolates), Leuconostocs (56), Mesophilic Lactobacilli (54), Pediococci (8) and Enterococci (2). Eighty-four of the isolates produced mainly malty, spicy or sulfide flavours in pasteurised whole milk, and were not characterized further. Some good producers of diacetyl-acetoin in milk (>100 mg/L) were found among a total of 129 LAB selected, although the isolates were generally less acidifying and less proteolytic than many of those obtained 10–15 years ago. The results suggest that the microflora in cheese-making environments have undergone changes, with the most evident difference being the practical absence of Enterococcal strains among the current isolates.