Dynamics of lactic acid bacteria in “Pecorino di Tramonti”—a ewe’s milk cheese—with particular emphasis on enterococci: a preliminary study

Abstract

The autochthonous lactic microflora involved in the production of the artisanal “Pecorino di Tramonti” cheese—a ewe’s milk cheese—was evaluated at the date of production and during ripening. Two batches, spicy and mild (not spicy) cheese, of premium quality Pecorino di Tramonti were produced from raw ewe’s milk without starter cultures, according to a very traditional technique. Lactic acid bacteria were monitored by counting on selective media. Counts for mesophilic rods and cocci on MRS and LM17 ranged from 6 to 8 Log CFU/g, respectively, during the entire ripening, but different growth trends could be observed between the two kinds of cheese. Enterococcal levels increased during the 1st month and decreased thereafter throughout ripening. A total of 169 cultures was selected randomly and identified by numerical analysis of ribopatterns. Ribotypes could be grouped in five clusters corresponding to different taxons. Enterococcusfaecium proved to be the dominant species, followed by Lactococcuslactis subsp. lactis, L. lactis subsp. cremoris, Enterococcus faecalis and Enterococcus durans.