MOLECULAR CHARACTERIZATION OF SOME PATHOGENIC BACTERIA ISOLATED FROM MAYONNAISE

Abstract

The purpose of this study was to determine the molecular characterization of some pathogenic bacteria isolated from commercial and small producers mayonnaise sold in restaurants and supermarkets in Assiut governorate. In the present study, the samples were analyzed for the presence of Salmonella spp., listeria spp. and staphylococcus aureus and according to microbiological analysis, Salmonella spp., listeria monocytogenes and staph. aureus were detected in 3 of 40 (7.5%), 3 of 40 (7.5%) and 7 of 40 (17.5%) of examined samples of small producers mayonnaise, respectively. The examined samples of commercial mayonnaise were free from salmonella spp. and listeria spp. but staph. aureus could be detected in 2 samples in a percentage of 5%. The presumptive isolates were further confirmed by PCR using specific primers of Salmonella invA isolates, L. monocytogenes 16S rRNA gene and Staph. aureus clfA gene and serotyping of Salmonella. These results indicated that small producers mayonnaise samples may contain pathogenic bacteria and thereby represent a risk to the consumers in regard to foodborne diseases. Thus, it is essential to include the effective hygiene practices as an important safety measure in the production of small producers mayonnaise. Bacterial loads were detected in mayonnaise including hazardous bacteria in spite of a high acidity of the product. This high light the importance of improving production situations and hygienic status in ready to eat foods establishments.