الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
The present study was undertaken to determine the incidence and distribution of Listeria species in table eggs and some egg-based product samples.Genotyping of L. monocytogenes isolates were determined to detect 16 SrRNA gene as a target by using Polymerase chain reaction.A total of 130 samples including 40 balady hens’ eggs, 40 farm hens’ eggs, 25 cream cakes, and 25 mayonnaise samples were collected randomly from Assiut city and analyzed for the presence of Listeria species.
The study revealed that 6 (15%) and 4 (10%) of the shell and content of balady hens’ eggs respectively, 2 (5%) and 5 (12.5%) of the shell and content of farm hens’ eggs respectively, 4 (16%) of cream cakes were contaminated with Listeria species on the other hand Listeria species failed to be detected in the examined mayonnaise samples.
Out of 40 balady hens’ eggs samples examined in this study, Listeria species were isolated from 15% of the egg shell including 2 (5%), 1 (2.5%), 1 (2.5%), 1 (2.5%), and 1 (2.5%) L. monocytogenes, L. ivanovii, L. welshimeri, L. innocua and L. murrayi respectively, and were isolated from 10% of the content including 2 (5%), 1 (2.5%), 1 (2.5%), L. monocytogenes, L. welshimeri, and L. innocua respectively, while other Listeria species couldn’t be detected.
Among 40 farm hens’ eggs samples examined in this study, Listeria species were isolated from 5% of the shell including 1 (2.5%), and 1 (2.5%), L. monocytogenes, and L. ivanovii respectively, and were isolated from 12.5% of the content including 1 (2.5%), 1 (2.5%), 2 (5%), and 1 (2.5%) L. monocytogenes, L. ivanovii, L. welshimeri, and L. innocua respectively.
The incidence of Listeria species in cream cake samples was 16% including 2 (8%), 1 (4%) and 1 (4%) L. monocytogenes, L. innocua, and L. grayi respectively.This study revealed that L. monocytogenes was the most predominant isolate. PCR was carried out for the detection of 16SrRNA gene for L. monocytogenes isolated from eggs and cream cake samples, all isolates showed an amplification of 1200bp fragment specific for the 16SrRNA gene with total percentage of 100%.