Molecular Epidemiology And Risk Analysis Of Campylobacter Based On Pork Production Chain

Campylobacter is an important foodborne pathogen,and the diarrhea caused by it is among the highest in bacterial diarrhea,causing a huge burden on the social economy.As an important host of Campylobacter,pigs leak the contents of the intestine during the production and processing of pork.Manual operation and equipment can cause a large number of Campylobacter to contaminate the carcass of the pig,which endangers human health.Collect epidemiological data of Campylobacter in the process of pork production and processing,and study its epidemiological laws in combination with molecular typing techniques to understand its propagation patterns and traceability.To further study the risks to human health caused by Campylobacter in pork,and to provide scientific advice for risk decision-making,this study based on epidemiological data to establish a quantitative microbiological risk assessment,the risk of caustic mycosis caused by eating pork to evaluate1 Epidemiological Study on Campylobacter in Pork Production ChainPork samples from farms,slaughterhouses and markets were collected and 10 steps were collected for Campylobacter monitoring.The strains of Campylobacter isolates from the same batch were selected for multi-site sequence molecular typing.The results show that before slaughter,after gutting,the market is the important parts of Campylobacter contaminated pork.The MLST results obtained two homologous complex types and 17 sequence types.The MLST results were clustered and the results showed that all isolates were divided into 7 clusters.One of the clusters containing Campylobacter covered all the pork production chains,indicating that the Campylobacter contamination during the production and processing of pork is closely related to the breeding stage.2 Quantitative risk analysis models for exposure assessment of Campylobacter during pork processingBased on the epidemiological data of Campylobacter in the process of pork production and processing in the first chapter,the distribution data of the positive rate and carrying capacity of Campylobacter in pork during the operation of each production and processing link were fitted and fitted according to the fitted distribution function.During the production and processing of pork,the exposure model of Campylobacter was used.Finally,Monte Carlo simulation technology was used to simulate the carrying capacity of Camplobacter and the positive rate of Campylobacter in pork during the processing of pork production.The simulation calculation of the exposure assessment model was established to obtain the contamination of Campylobacter in pork production and processing process.The simulation results were compared with the actual monitoring results.The prediction results were consistent with the actual results.The repetitiveness of the model was verified and the error was less than 1%.The results show that the model has a more stable forecasting ability3 Quantitative risk assessment models on Campylobacter in porkTaking the Curvularia exposure assessment model in Chapter II of pork production and processing as the core,and referring to some international models and poultry consumption models,a quantitative risk assessment of the risk of human infection and pathogenicity caused by Campylobacter in pork was conducted.Establish an exposure assessment model for the pork production chain and consumption process.Using the quantitative risk assessment model established in this study,the probability of Campylobacter infection and disease caused by consumption of pork was calculated.The average value was 0.00638,0.00217;that is,419 people were consumed per 100,000 people due to pork consumption every year.Infected,142 pathogenic.This value is higher than the quantitative risk assessment of Campylobacter in poultry meat,and 118 people per 100,000 people are pathogenic.This may be because there is no freezing stage in pork,and a large amount of reference is made to the Campylobacter model in poultry meat,resulting in more realistic model predictions.The situation is high.After sensitivity analysis,identify the key factors.By changing the control effect of each control point,the control effect is evaluated.The simulation of key control factors revealed that when the Campylobacter carrying capacity was decreased by one log value,the control of the growth of Campylobacter was best before slaughter(a decrease of 21.89%).Because there are many modeling methods to choose from,it is necessary to choose the right model according to different situations to build a suitable risk assessment system.Many factors such as complicated operation processes in the pork production process increase the difficulty of establishing a model.After the model is established,according to the specific The difference in production conditions and the effect of different control measures are quite different.In the absence of data,we can only discuss the specific cost-effectiveness of the control strategy for the time being,so as to be able to refer to the specific control measures and strategies.