Introduction: The contamination of poultry carcasses in slaughter house according to the number of poultry and systems has a risk for human health. In this research some Gram- negative bacteria were isolated from alimentary canal. In addition, serotyping of Salmonella was performed.

Materials & methods: Four hundred alimentary canal specimens from 80 industrial poultry farms (5 chickens per farm) were sampled and sent to Ilam University laboratory. Gram-negative bacteria were isolated and identified by mean of standard biochemical tests. The serotyping of salmonella isolates was carried out by the Razi Vaccine and Serum Research Institute, Karaj, Iran. Sequence analyses for a representative selection of Gram-negative bacteria were performed commercially by Macrogen, South Korea.

Findings: Out of 80 flocks, species of some genera including Proteus, Escherichia, Enterobacter and Salmonella were isolated form 75 (94 %), 40 (50%), 30 (38%) and 5 (6%) flocks, respectively. The results showed that three salmonellae were identified as Salmonella O7 (Group C1), one O8 (Group C2) and the other as O9 (Group D).

Discussion & Conclusions: The high presence of the bacteria in poultry’s alimentary tract in slaughter house immediately before they were slaughtered may be a pose for human health hazards. Thus, based on the findings of this study poultry’s alimentary tract bacteria should be considered as a potential source of contamination for the public health.