Yeasts in the raw ewe’s milk

ABSTRACT

Background: The contamination of milk by fungi, often represented by potentially pathogenic species, may pose a riskfor consumers, when the product is consumed in natura or even in the processed form. Also, it should be considereddetrimental effects in the processing of milk derivative products. In relationship to other milk producing animal species,ovine milk occupies the fourth place in the global production, contributing with 1.3% from the grand total. In Brazil, themajority of sheep’s milk is used for the production of fine cheeses and yogurts. The aim of this study was to evaluate theoccurrence of yeasts in the ewe’s milk.Materials, Methods & Results: Five hundred and eighty-eight milk samples were obtained, of which 106 came fromanimals with clinical mastitis and 482 from healthy animals. Aliquots of 0.1 mL milk were first plated on acidified yeastmedium agar. Then the yeast colonies were streaked onto Hicrome Candida Differential Agar Base (HIMEDIA®) andsubjected to biochemical analysis by API 20C system (Biomérieux®). The identification was made by using conventionalstandardized test panel. A total of 60 fungal species were isolated from 53 (9%) milk samples. They were classified intothe following genera Candida spp. (70.00%), Rhodotorula spp. (11.70%), Trichosporon spp. (6.70%), Geotrichum spp.(5.00%), Pichia spp. (5.00%) and Cryptococcus sp. (1.70%). Potentially pathogenic yeasts were identified as Candidaglabrata (n = 8), C. tropicalis (n = 6), C. parapsilosis 1 (n = 5), C. albicans (n = 4), Pichia guilliermondii (n = 3) andTrichosporon asahii (n = 1).Discussion: The majority of sheep’s milk is not directly consumed by the population, being mainly destined for the production of cheeses of important market value. Therefore, typical sensorial and organoleptic characteristics found in cheese maybe influenced, as early as the beginning...