Purpose: The study determined the prevalence, antibiotic sensitivity profile and biofilm-forming abilities of CC and LM isolates along the processing lines of swine slaughtered for human consumption.
Methods: A six-month study (May–October, 2014) isolated CC and LM and estimate the contamination level along pork processing line. Three hundred swabs (2 cm² area) and tissue samples were collected during the processing (Rectal swab before slaughtering, Skin swab before scalding/singeing, Skin swab after scalding/singeing, Pool of skin swab from cranial part, Pool of skin swab from caudal part, Swab of small intestine, Knife swab, Table swab, Liver tissue, and Kidney tissue). Scalding and singeing were the two processing methods considered in this study. Antibiotic sensitivity was assessed using the disc diffusion method. Biofilm mass was determined over a 5-day period using the Crystal Violet Binding Assay.
Results: Overall prevalence of CC and LM was 29% and 14%, respectively. High aerobic plate counts (log 7 CFU/cm² - log 8 CFU/cm²), higher than the < log 6 CFU/cm² stipulated by International Food Standard Agencies. Campylobacter count (4.14 - 5.77 mean log CFU/cm2 for scalding process and 0.995 - 5.93 mean log CFU/cm2 for singeing process) and LM count (1.76 - 4.24 mean log CFU/cm2 for scalding process and 0.995 - 3.27 mean log CFU/cm2 for singeing process) were within the international limit (log 2 CFU/cm² - log 7 CFU/cm²) stipulated by International Food Standard Agencies. Generally, CC strains were very resistant to all the antibiotics tested, while LM was moderately sensitive to all antibiotics used. All strains produced biofilm; however, biofilm forming abilities was not significantly different (P > 0.05) between strains.
Significance: The biofilm forming abilities of these strains will lead to persistence of these pathogens in food and food processing environment.