DNA typing methods for differentiation of yeasts related to dry-cured meat products

Abstract

RFLP analysis of the ITS and 18S rDNA, RAPD-PCR using mini- and microsatellite primers and RFLP analysis of mitochondrial DNA were examined to discriminate yeasts related to dry-cured meat products at species and strain level. Seven species and 35 strains of yeasts usually found in dry-cured meat products were tested. RFLP analysis of the ITS1-5.8S rDNA-ITS2 and 18S rDNA did not allow the separation at species level of all of the species tested. RAPD with a M13 primer was found to be useful for differentiation of Rhodotorula mucilaginosa, Candida zeylanoides, Yarrowia lipolytica, Debaryomyces hansenii and Saccharomyces cerevisiae. However, no differences were observed between Debaryomyces polymorphus and Pichia carsonii. RAPD analysis with microsatellite primers (GACA) 4, (GTG) 5 and (GAC) 5 enabled discrimination at species and strain level. However, the degree of discrimination by means of RAPD-PCR depends highly on the primers used. Thus, the PCR fingerprinting with primer (GACA) 4 enabled a higher level of discrimination than primers (GAC) 5 and (GTG) 5. The RFLP analysis of mtDNA allowed the discrimination at the species and strain level except for R. mucilaginosa, where no polymorphisms were observed in the strains tested. RAPD analysis with primer (GACA) 4 and the restriction analysis of mtDNA used in the present work are useful for the differentiation at species and strain level of yeasts related to dry-cured meat products.