Microbiological Quality and Incidence of Some Pathogenic Microorganisms in La Serena Cheese Throughout Ripening

Fifteen batches of La Serena raw ewes' milk cheeses have been analyzed at different stages of ripening for microbiological quality and occurrence of some pathogenic microorganisms. Values of pH, percent moisture content, and percent NaCl were also determined. The microbiological quality was in general very poor, because 46.6% of samples contained levels between 10⁴ and 10⁷ CFU/g of coliforms and fecal coliforms, at 60 d of ripening. In spite of this, staphylococci were only detected, at low levels, in two out of 15 60-d ripened cheeses. Salmonella arizonae was the only species of Salmonella detected. Listeria monocytogenes was isolated in five samples in very low levels. Campylobacter jejuni was not found in any of the cheeses analyzed.