Development of a PCR-culture technique for rapid detection of yeast species in vacuum packed ham

A rapid assay for detection of yeast species in vacuum packed ham has been developed based on the polymerase chain reaction (PCR) coupled to a 24 h pre-enrichment at 25 °C. DNA was isolated from yeast inoculated ham samples and amplified using primers specific for the 18S rRNA gene sequences of yeasts. A detection limit of 102 CFU/cm2 was achieved following enrichment of samples experimentally inoculated with three yeast species frequently associated with meat products spoilage: Debaryomyces hansenii, Yarrowia lipolytica, and Kluyveromyces marxianus. Likewise, commercial sliced and vacuum packed ham samples were analysed using the PCR-culture technique. The results obtained in this work show that PCR amplification of a conserved region of the 18S rRNA gene in the yeast species could be potentially used as a rapid tool for detection of low levels of viable spoilage yeasts in meat products.