Hefei Slaughter Pigs Health Survey

There are three major standards including aerobic bacterial count, Ccoliformbacteria and pathogenic bacteria for microbiological examination of food hygiene.Listeria monocytogenes (Lm) and Salmonella are two of most importantfood-borne pathogens. Lm could even cause meningitis, septicemia and abortionof pregnant women, and the mortality rate could be as high as 30％. All over theworld, Salmonella infection causes the most serious bacterium food poisoning innumber of cases and population.Accordingly, the present study was investigated①the Lm contamination rate in marketing pork,②the Lm contaminationstatus in slaughter process of abattoir, and③aerobic bacterial count andcontamination of Coliform bacteria and Salmonella in pig carcass. This study wasto know the hygienic situation of slaughter pig in Hefei, and consequently,provide a scientific basis for improving the hygienic management of the slaughterprocess, for establishing the pig slaughter Hazard Analysis and Critical ControlPoints (HACCP) system, for strengthening the hygiene monitoring for pigslaughter, processing, storage, transportation, marketing, for improving hygienequality of pork products, and finally, for preventing and controlling food-borneillnesses from Salmonella and Lm.1 Investigation of Lm contamination in marketing porkThe contamination of Listeria monocytogenes in marketing pork wasdetected by polymerase chain reaction (PCR). As a result, four Listeriamonocytogenes strains were isolated in 370 pork samples, and the positive ratewas 1.08％. It indicated that the marketing pork was contaminated by Listeriamonocytogenes with lower level and there was possibility of listeriosis andpotential danger of food poisoning in Hefei. The hly gene of two Lm isolates wassequenced from p190 to p970 nucleotide (DNA, 780 bp) and compared with thesequences of 14 reference strains registered in GenBank. The results showed thatthe difference distance of Lm hly gene nucleotide sequences had no relationshipwith its distribution, origin and source.2 Investigation of Lm contamination in slaughter processBased on the contamination of Lm in marketing pork in Hefei, furtherretrospect survey on the contamination rate of Lm in the slaughter process in 5designated areas was conducted by PCR. Altogether, 750 samples were collectedfrom the slaughtered pig skin and carcass surface, ground and water used inslaughtering. Among them, none was Lm positive, which was not identical withthe previous reports. As for the reason, it might be due to the low concentration insamples (less than 10~2 cfu/ml), the influence of processing factors, andcontamination of many other bacterium. 3 Investigation of aerobic bacterial count, Coliforms bacteria and Salmonellacontamination in slaughtered pig carcassBase on the criteria of national standards, 700 samples from pig carcasssurface and meat were examined for aerobic bacterial count, Coliform bacteriaand Salmonella contamination. The results showed that the overall positive rateof aerobic bacterial count and Coliform bacteria reached 47％and 22.5％respectively, while the overall positive rate of Salmonella in carcass surface andmeat samples was 24.2％and 17％respectively. Among them, the mainserogroups were group B and group E1, and the dominant serotype was S.reading.There was a positive correlation between Coliform bacteria and Salmonellacontamination. It indicates that it is seriously necessary to improve the quality ofpig carcass hygiene and enhance the higiene level of production and processing.It is helpful to reduce the Salmonella contamination if it was paid more attentionon the control of Coliform bacteria. It is also helpful to insure healthy pig andunhealthy pig isolating, reduce the Salmonella contamination to processingsurroundings and products if it was brought into effect on Anti-mortemmanageness and Anti-mortem inspection. Moreover, Salmonella dominant strainsdistribute irregularly in different regions.