Influence of ripening conditions on survival of brucella melitensis in traditional lighvan cheese (ewe milk cheese)

Abstract

In developing countries, brucellosis is a reported and in most of cases, consumption of raw milk and traditional cheeses contaminated with Brucella spp., especially B. melitensis, is the main cause of disease. The aim of this study was to evaluate the effects of ripening conditions (ripening temperatures: 4, 9 and 14°C and salt concentrations: 8, 12 and 15%) on survival of B. melitensis in traditional Lighvan cheese (a typical Iranian brine-ripened cheese) manufactured with raw ewe’s milk during 150 days of ripening. Results showed that the viable counts of B. melitensis changed significantly (p< 0.01) as a function of storage temperature. B. melitensis survived significantly better at 4°C and 9°C than 14°C (p<0.01). All of salt concentrations (8, 12 or 15% NaCl) significantly (p<0.001) affected the inactivation of pathogen. B. melitensis had been completely eliminated at the end of ripening period (150 days). Our findings indicated that the using of hurdle technology (the two limiting factor, namely temperature and salt concentration), is a powerful tool to eliminate B. melitensis in Lighvan cheese after at least 5 months of ripening.