Microbiological changes throughout ripening of goat cheese made from raw, pasteurized and high-pressure- treated milk

The bacteriological quality during ripening of raw (RA) pasteurized (PA; 72 degreesC, 15 s) and pressure-treated (PR;500 MPa, 20 degreesC, 15 min) goa t milk assessed by enumeration of total bacteria, psychrotrophic bacteria, Enterobacteriaceae, lactobacilli, enterococci, Micrococcaceae and lactococc i was evaluated. The high pressure treatment applied was as efficient as pa steurization in reducing the bacterial population of milk. Experimental che eses were made from RA, PA and PR milks to study the microbial population d uring ripening. Lactobacilli and lactococci were the predominant microbiota present during ripening in all the cheeses. There were no differences in n umbers of starter bacteria during ripening However, lactobacilli counts for RA milk cheese were significantly higher than for PA and PR cheeses in all the ripening stages studied. Micrococcaceae and enterococci remained at a secondary level, and no differences were observed between cheeses at the en d of ripening. On the other hand, the number of Enterobacteriaceae decrease d during ripening, but faster in PR milk cheese than in PA and RA milk chee ses. The results of this study suggest that goat cheese made from PR milk h ad similar microbiological characteristics to PA milk cheeses. (C) 2001 Aca demic Press.