Prevalence of Listeria species and Listeria monocytogenes serotypes in ready mayonnaise salads and salad vegetables in Iran

摘要

Three hundred samples of ready mayonnaise salads and salad vegetables were used forisolation of?Listeria?spp. by?ISO 11290-1. The isolates were?identified using?biochemical tests, further confirmed by duplex PCR and differentiated via conventional agglutination serotyping. A total of 8.7% of the samples harboured?Listeria?spp., including 7%?Listeriamonocytogenes, 1%?Listeria innocua?and 0.7%?Listeria welshimeri. The?L. monocytogenes?isolates were divided into four serotypes of 1/2a (61.9%), 1/2b (19%), 3b (4.8%) and 4b (14.3%). The prevalence of?L. monocytogenes,?especially serotype 4b indicates that ready mayonnaise salads and salad vegetables could be potent sources of listeriosis.