Microbiological changes in ‘San Simón’ cheese throughout ripening and its relationship with physico-chemical parameters Original Research Article

Changes in the microbial flora of San Simón cheese, manufactured from raw milk without the addition of starter cultures, were studied during the manufacture and ripening, with the object of contributing to the characterization or typifying of this variety. Microbial counts from cheese surface were, on the whole, 1 log unit lower with respect to the ones taken in the core of the cheese, with the exception of the counts in MSA and OGYEA media. Lactic acid bacteria (major microbial group) reached their maximum counts in 4-week-old cheese from core samples, although on the surface of the cheese the maximum count of lactococci and leuconostoc were obtained after 2 weeks. Other microbial groups (Micrococcaceae, Enterococci and Enterobacteriaceae) reached their maximum counts in 1-week-old cheese and decreased slightly afterwards during ripening. The decrease of the Enterobacteriaceae was a little more striking, although they did not disappear completely at the end of the ripening process. The evolution of major physico-chemical parameters investigated during manufacture and ripening of San Simón cheese, contribute to the slight decrease of all microbial groups, since the parameter values during ripening were not markedly dysgenic for any of the microbial groups investigated.