A Survey Of The Infection Status Of Foodborne Pathogens For Pork Products From Pig Slaughterhouse In Beijing

In this paper,the food-borne pathogen contamination caused by E.coliO151:H7,S.enterica,L.monocytogenes and C.jejuni in pig products of slaughterhouses located in Beijing were investigated by the multiplex PCR which were designed originally.The nunmber of slaughtered pigs of the ten slaughterhouses were 7.4283×106,7.8853×106,6.7989×106 and 5.7449×106 separately from 2013 to 2016.The ratio slaughtered pigs outside Beijing to all the slaughtered pigs of ten slaughterhouses of Beijing was up to 84.64%?74.08%?72.69%? 73.92%from 2013 to 2016.There was a regular pattern between the number of slaughtered pigs and seasons.In detail,amount of slaughtered pigs was maximum:7.891 ×105 in January and the amount was minimum in September:3.02×105.The ratio of diseased pig to all the slaughtered pigs in Beijing from 2013 to 2016 was 1.56 ‰,1.29 ‰,0.80‰ and 0.46‰ respectively.The ratio was maximum in July:1.41‰ and minimal in May:0.75 ‰.Among ten main provinces,the number of diseased pigs from Heilongjiang was maximum:2.52‰.And the number of diseased pigs from Tianjin was minimal:0.27‰.600 samples of liver and lung detected by clear lesions were collected from five pig slaughterhouses in Beijing during the four different seasons.The positive rate of E.coliO157:H7,S.enterica,L.monocytogenes and Cjejuni was 0.50%,5.33%,2.67%and 1.33%by using multiplex PCR.The positive rate changed along with the seasons.The minimum positive rate was in June:4.67%and the maximum positive rate was in September:18.00%.The samples of slaughtered pigs from Heilongjiang had the highest positive rate:16.67%,while the samples from Beijing had the lowest positive rate:0.83%.Two sets of triplex real-time fluorescent quantitative PCR were settled.The result showed that the sensitivity of each simplex PCR assay of genome DNA and bacteria solution had good linear correlation.Compared with the simplex real-time PCR assay,the sensitivity of the S.enterica and the L.monocytogenes detected by using the triplex PCR assay does not reduced except for the E.coliO157:H7.The sensitivity of S.enterica,L.monocytogenes and C.jejuni by adapting the single detecting system was the same as by using the real-time PCR detecting system for these three pathogens.The standard curve with Ct value against lg(CFU/mL)showed good linear correlation.100 samples of liver and lung were examined by two sets of triplex real-time fluorescent PCR established originally.All positive samples were consistent with the standard testing method except for one L.monocytogenes positive samples,In summary,the data which came from diffrent seasons and pig slaughter houses provide the valuable information for the rational allocation of pig resources and creation of soientific regulatory measures.In conclusion,the established two sets triplex real-time assays are reliable and practical to detect four foodborne contamination caused by E.coliO157:H7,S.enterica,L.monocytogenes and Cjejuni for pork products.It also provides new techniques for detecting the infectious bacteria in clinical specimens.