Characterization of yeasts associated with Portuguese pork-based products.

Yeasts from pork-based products, such as country-cured hams and several types of bacon, were studied. Contamination levels ranged from 10(3)-10(9) CFU/g of fat. Identification using a simplified method (SIM) showed that the predominant species were Debaryomyces hansenii, Cryptococcus laurentii, Cryptococcus humicolus, Debaryomyces polymorphus and Pichia guilliermondii. Lipolytic activity was observed in 24 out of 29 of the isolated strains and was not a determinant for attaining high levels of contamination. The analysis of yeast long-chain fatty acid composition for most isolated strains showed a predominance of the acid C18:1 followed by decreasing proportions of the acids C16:0, C18:2, C18:3, C18:0 and C16:1. The fatty acid profiles were roughly similar for all yeasts analyzed suggesting that in these types of pork-based products the yeast lipid composition may have an ecological significance.