Quantification of Enterococcus faecalis and Enterococcus faecium in different foods using rRNA-targeted oligonucleotide probes

The abundance of Enterococcus faecalis and Enterococcus faecium in different Spanish foods was evaluated by using taxon-specific oligonucleotide probes targeted against extracted rRNA. Two satisfactory methods were developed for RNA extraction. Although the yield and purity of total RNA obtained largely depended on the type of food, method 1 should be recommended. The quantitative results obtained with the oligonucleotide probes DB6 for E. faecium and DB8 for E. faecalis showed that these two species accounted for less than 0.5% of the active microflora in all the food samples tested. These results suggest that enterococci form only a minor portion of the microflora of these products.