Background and Aim : Changing lifestyles and daily needs to fruits and vegetables, as well as new diseases, have increased the use of this part of the food pyramid. Accordingly, it is important to prepare ready-to-eat packages with minimal
contamination with pathogenic bacteria, which are abundant in vegetables. Among the isolated bacteria, the rate of
contamination of leafy
vegetables with Escherichia coli was higher than other bacteria, as most intestinal diseases are caused by the consumption of
vegetables associated with this microorganism. Therefore, in the present study, the
contamination of packaged salad and
vegetables with Escherichia coli, with more importance, as well as other pathogenic bacteria were assessed.Methods : Total of ۷۰ vegetable and salad samples were alternately collected from packaging companies. The rate of
contamination was examined by using microorganism total counts, and coliform bacteria counts tests as well as identification of Escherichia coli bacteria and enterococci according to ISO (Iranian national standards organization standard) number ۱۰۰۸۲. In addition, molecular confirmation test was performed by PCR method due to food microbiology protocols recommended by standards organization, in order to detect the uidA gene for initial confirmation of Escherichia coli species. stx۱, stx۲ and eae genes were then detected by using multiplex-PCR to determine Escherichia coli pathotypes.Results : The obtained data showed microbial
contamination with different rates in all samples. So that the average microorganism total count and coliform counts in
vegetables and salads samples were ۳۰۰×?۱۰?^۵ Cfu/gr and ۱۶۰۰×?۱۰?^۲ Cfu/gr, respectively. ۳۵ (%۵۰) of the samples were positive for Escherichia coli, and the PCR result confirmed this result. Enterococci bacteria were identified in ۱۴ (%۲۰) samples.Conclusion : The results showed high rate of coliform contamination. Despite the low rate of
contamination with other studied bacteria, due to the importance of pathogenicity of isolated bacteria, it is necessary to reconsider the washing and packaging processes in order to reduce this contamination.