Investigation And Source Tracing On Contamination Of Salmonella In The Broiler Slaughter And Processing Production Chain And Analysis Of Their Resistance

Salmonella are a kind of serious foodborne pathogens, and the food poisoning causedby Salmonella rank the first or second in the world. In recent years, due to the abuse ofantibiotics, drug-resistance of Salmonella has been constantly enhanced accompanyingwith continuously widened spectrum of multiple drug resistance, which has caused greatdifficulties on prevention and treatment of salmonellosis. Broiler is the main carrier of thespread of Salmonella, and its slaughter and processing often lead to serious Salmonellacontamination. In order to prevention and control the contamination, the investigation,source tracing and resistance analysis of Salmonella in broiler production chain should betaken, which also can provide scientific basis for rationally readjusting the use ofantibiotics.The samples on carcasses, cloaca, crop contents of broiler, environment, equipmentsand apparatus surface were obtained from the production chains of three broiler slaughterand processing plants(FX,LA, GZ). National standards and PCR were performed for theisolation and identification of Salmonella, then enterobacterial repetitive intergenicconsensus PCR(ERIC-PCR) were used for subtyping of isolates and the NTSYS-pc2.10software was applied to make clustering analysis. A total of24among the investigated1349samples were detected from FX, LAand GZ, the total detected rate was1.78%, thedetected rate at FX was0.18%, which was lower than that of LA(4.49%) and GZ(2.39%),and the difference was significant(P<0.01).In FX, Salmonella was only isolated from oneeviscerated broiler carcass, which belonged to V genotype, in LA, genotype I isolated fromcontents of crop and carcasses after chilling, in GZ, genotype VI were isolated frombroiler cloaca, fingers, eviscerators’ glove and carcasses after slaughtered, defeathering andevisceration, genotype IV were isolated from the eviscerators’ glove and carcasses afterdefeathered and chilled, but genotype III and II could be isolated from the surface oftransportation and fingers respectively. The genotype of Salmonella isolated frompre-slaughter broiler cloaca or contents of crop is consistent with these from some ofbroiler carcasses, equipment and apparatus, and these Salmonella also can lead tocross-contamination in the defeathering, evisceration and chilling. The results indicatedthat Stages of pre-slaughter, defeathering, evisceration and chilling can lead to Salmonellacontamination in the plants.By the Kriby-bauer agar diffusion method,20kinds of antibiotics were choosed for antibiotics sensitivity tests. The doxycycline and streptomycin got the highest resistancerate of50%, while the most sensitive antibiotics was imipenem with sensitivity rate of upto100%among the24strains of Salmonella. In13strains of drug-resistant Salmonella,15.4%were resistant to3-4antibiotics,23.1%to9-11antibiotics,53.8%to12-14antibiotics, and the multiple drug resistance spectrum wasSTR-DO-TC-AM-AMC-CFZ-TM. The results indicated that broiler products is theimportant source of infection of multi-drug resistant Salmonella, which caused by theabuse of antibiotics in farm.