Causal hidden variable model of pathogenic contamination from pig to pork

Abstract

Risk assessments relating to food safety over more than one step along a production chain are frequently hampered by lack of detailed quantitative data. This study set out to develop a Bayesian hidden variable model to integrate available limited data of the combined occurrence of three bacterial pathogens, Listeria monocytogenes, Yersinia enterocolitica and Yersinia pseudotuberculosis, with causal assumptions along three steps of pork production chain. The pathogen occurrence data were animal specific both on conventional and organic pig farms and at the abattoir, but merely farm specific at meat cutting plants. The model was able to incorporate all data concerning different types of testing at different steps of the chain, and missing data values were dealt with in a straightforward manner. It provides a tool for quantitative risk assessments and for estimating the causal risk mitigation effects by combining external data with the specific follow-up data. Intervention effects are provided with Bayesian credible intervals indicating the uncertainty due to all information sources included in the model. Combined prevalence in Finnish pork was estimated to be 1-11% and it could be reduced to 0-2% if head was removed intact and rectum sealed off.

Piglets Are a Source of Pathogenic Yersinia enterocolitica on Fattening-Pig Farms

“…The carcasses become contaminated with the pathogen in the slaughterhouses by contamination from tonsils and intestinal contents (8,22). The level of carcass contamination can be reduced with such hygiene practices as removing the head and bagging the rectum (1,20,26,28), but these alone fail to completely eliminate the carcass contamination. Therefore, reducing the occurrence of the pathogen at the farm level is also needed.…”

Enteropathogenic Yersinia in the Pork Production Chain: Challenges for Control

“…At the same time, the prevalence of Y. enterocolitica O:3 in the tonsils of sampled pig increased from 56% to 72% (Christensen and Lüthje ). It has been estimated that the combined prevalence of Listeria monocytogenes, Y. enterocolitica , and Y. pseudotuberculosis detected (using isolation methods) in Finnish pork cuts for minced meat would decrease from 1% to 11% to 0% to 2%, if the both the removal of head with tonsils and bagging of the rectum were used (Ranta and others ). It has also been recommended that head meat should be cut in a separate room on a separate table (Borch and others ).…”

Simulation‐based assessment of Microbiological Criteria on Salmonella in poultry meat

“…In the absence of extensive longitudinal data from the whole food chain, statistical models can be used to describe such a link (Ranta J. et al, 2010). Based on these models, simulations can be made, under certain scenarios or assumptions, to provide risk managers with useful information.…”

“…In the next section, as in Ranta et al, 2010 , a state space model based on idea of hidden carriage describing is proposed:…”