Acta Veterinaria et Zootechnica Sinica ›› 2025, Vol. 56 ›› Issue (10): 5137-5147.doi: 10.11843/j.issn.0366-6964.2025.10.033

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Investigation of Salmonella Contamination in Pork Production Process and Reduction Control of Key Points

MENG Chuang1,2,3(), JIN Xuanchen1,3, PENG Tongtong1,3, ZHAI Xianyue1,2,3, KANG Xilong1,2,3, JIAO Xinan1,2,3, PAN Zhiming1,2,3,*()   

  1. 1. Jiangsu Key Laboratory of Zoonoses, Yangzhou University, Yangzhou 225009, China
    2. Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
    3. Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality of Ministry of Agriculture and Rural Affairs, Yangzhou University, Yangzhou 225009, China
  • Received:2025-01-03 Online:2025-10-23 Published:2025-11-01
  • Contact: PAN Zhiming E-mail:mengchuang@yzu.edu.cn;zmpan@yzu.edu.cn

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Abstract:

This study aims to explore the prevalence and critical control points of Salmonella within the pork production chain, encompassing pig farms, slaughterhouses, and pork markets, through Salmonella isolation and molecular typing. Samples from pig farm, slaughterhouse and pork markets with interconnected were collected for Salmonella isolating and serotyping. Pulsed field gel electrophoresis (PFGE) methods were used for molecular typing of Salmonella isolates to analyze critical control points of contamination. The effect of increase washing times on Salmonella depletion was evaluated by comparing the changes of Salmonella isolation. The results showed that 417 Salmonella strains were isolated from 950 different types of samples with a total isolation rate of 43.9%. Among of them, 80 fecal samples from farm, 470 pig carcasses and environmental wipe samples from slaughterhouse and 400 pork samples from supermarkets showed isolation rate of 28.8%, 34.5% and 56.8%, respectively. In different slaughtering stages, samples after splitting showed the highest separation rate of 51.0% while the separation rate of the samples after chilling was significantly reduced to 23.0% (P < 0.05). Nine different serotypes were identified from the Salmonella isolates, and the predominant serovars were Salmonella Derby (39.6%), Salmonella Typhimurium (38.1%), Salmonella London (10.3%) and Salmonella Rissen (8.4%). There were 32 pulsotypes were identified in 67 Salmonella Derby isolates by PFGE analysis, of which the isolates from slaughterhouse samples contain the most widely pulsotypes distribution. The isolates from the same sampling visiting appeared in the same pulsotypes, and there were pulsotypes contains isolates from farms, slaughterhouse, and markets with similarity more than 95%, indicating the characteristic of spreading along the production chain. Two times more washing operations for 1 min were added after splitting, which significantly reduced the average isolation rate of Salmonella from 41.7% to 20.0% (P < 0.01) in the subsequent slaughtering process. These results indicate that Salmonella can be spread along the pork production chain via cross-contamination at critical control points such as splitting, offering vital insights and guidance for the prevention and control of Salmonella in pork.

Key words: pork, production chain, Salmonella, PFGE, critical control point

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