Molecular detection of Salmonella isolated from eggs and egg-based products

Document Type : Original Article

Authors

1 Molecular Biology Research & Studies Institute, Assiut University, Egypt

2 Faculty of Veterinary Medicine, New Valley University, New Valley, Egypt.

3 Faculty of Veterinary Medicine, Assiut University, Egypt.

Abstract

This study aimed to investigate the prevalence of Salmonella in eggs and some egg-based products in Sohag city, Egypt. 120 samples of hen's eggs (Baladi & farm), mayonnaise and cream cake were examined for conventional and molecular detection of Salmonella. The samples were divided into egg-shell Baladi, egg-content Baladi, egg-shell farm, egg-content farm, mayonnaise and cream cake (20 each). All the samples were subjected for conventional enrichment culture. 25 g of each sample was added to 225 ml of 1% buffered peptone water and incubated at 37°C for 24 hours, one ml of the enriched media was then transferred to Rappaport-Vassiliadis broth and incubated at 40°C for 48h. A loopful was then streaked on Salmonella-Shigella agar to look for colorless colonies with a black center. Biochemical identification was performed using triple sugar iron agar test, lysin iron agar test and urease test. The results of conventional culture showed that 30% of egg-shell Baladi, 10% of egg-content Baladi, 20% of egg-shell farm and 15% of egg-content farm samples were positive for Salmonella. However, all of the mayonnaise and cream cake samples were Salmonella-free. The Salmonella isolates were then identified using PCR. The results by PCR showed that Salmonella were detected from 30% of egg-shell Baladi, 5% of egg-content Baladi, 15% of egg-shell farm and 10% of egg-content farm samples. Salmonella Enteritidis was isolated from only one sample of egg-shell Baladi and only one sample of egg-content farm, while no Salmonella Typhimurium was isolated from any of the samples.

Keywords

Files

Share

How to cite

Statistics