الفهرس 
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Abstract
This investigation was designed to estimate prevalence rate of Salmonella and E. coli in100 samples of frozen half cooked (packaged) and ready-to-eat sausage and nuggets (25 each) that collected from different supermarkets, grocery-stores, and restaurants in Assiut, Egypt.
Salmonella was recovered from 6 and 6% of the examined frozen half cooked (packaged) and ready-to- eat sausage and nuggets. Isolated Salmonella from packaged frozen Sausage were serotyped as S. enteritidis, S. typhimurium, and S.essen in the same percent (4%, 1/25 for each). The serovars isolated from packaged frozen nuggets were S. enteritidis and S.montevideo also in the same rate (4%, 1/25 for each).
Only one out of the 25 examined ready to eat Sausage samples had S. typhimurium (4% 1/25) and No Salmonella serotype was detected in the ready to eat nuggets (0%).
Molecular Identification using Polymerase chain reaction technique (PCR) showed 6 isolates were positive for Salmonella and produced the predicted 284bp amplification product.
E. coli was recovered from 14% varied between the frozen packaged and the ready to eat samples. In the frozen packaged sausage, the serotypes detected were O26: H11 (4%), O111: H2 (4%) O146: H2 (4%) and O127: H6 (8%); while in the examined ready to eat sausage samples, the most encountered serotypes were O26: H11 (4%), O111: H2 (8%) and O159 (4%) Regarding the packaged frozen nuggets, the detected serotypes were O26: H11 (4%), O111: H2 (4%) and O146: H21 (4%) while in the ready to eat nuggets, O44: H18 (4%) and O121: H7 (4%).
Molecular Identification using Polymerase chain reaction technique (PCR) showed 14 isolates were positive for E. coli and produced of its characteristic gene (phoA) that predicted 720bp amplification product.
Analysis of virulence genes of Salmonella showed that the prevalence of sopD, stn, and sopB was100% (n = 6) but the pefA was not detected. While, analysis of virulence genes in the E.coli isolates showed that the prevalence of papC gene was 100% in EIEC O159 (n = 1), 37.5% possessed stx1 gene in serotype ,O26:H11,87.5% possessed eaeA gene in serotype O111:H2 (n=4 ),O26:H11 ( n= 3) while stx2 was not detected in EHEC , eaeA gene was 66.5% in serotype O146:H21( n=2 ) inEPEC and STa ,CFAI genes were not detected in ETEC O127H:6 ( n = 2).
All the isolated Salmonellae (100%) are able to form biofilm with (red, dry, and rough (rdar) phenotype within 24-48 hours. The genetic factors csgD involved in biofilm formation are also involved in adherence and colonization of host tissues was identified in all obtained Salmonella isolates (100%). Like Salmonella, all isolates of E. coli produced biofilm CR agar and adrA gene was detected in all E. coli isolates.