Abstract:

According to the National Food Safety Standard, Food Microbiological Examination: Salmonella (GB 4789.4—
2010), CHROMagar medium was used for the isolation of Salmonella from 1 350 samples collected from broiler slaughter
and processing chain. The duplex PCR method for invA and hut gene was used to further identify the isolated strains. The
isolated Salmonella strains were tested for their antimicrobial susceptibility against 10 kinds of antibiotics (combination) by
using Kirby-Bauer method. The susceptibility was determined by the standard of Clinical and Laboratory Standards Institute
(CLSI, 2010). The results showed that 156 strains of Salmonella were identified from the samples. Approximately 13.53%
of the broiler feces samples were Salmonella positive. The occurrences of Salmonella contamination after defeathering,
bowel, evisceration and cleaning were 0.00%, 7.23%, 9.80% and 11.54%, respectively. The occurrences of Salmonella
contamination before and after chilling were 14.50% and 9.33%, respectively. For Salmonella isolated from broiler slaughter
and processing chain, the highest drug-resistance of all strains was nalidixic acid (100%) and ampicillin (85.90%). Many
isolates were resistant to trimethoprim/sulfamethoxazole (44.23%), gentamicin (39.10%) and tetracycline (35.26%). All of
the isolates were susceptible to ceftriaxon, and 53.85% of them were multi-drug resistance. The Salmonella isolates from
broiler slaughter and processing chain had 39 antimicrobial resistance profiles. Therefore, the contamination and drugresistance
of Salmonella were severe in the broiler production chain.

Key words: Salmonella, broiler slaughter and processing chain, contamination, antimicrobial resistance