Salmonella Typhimurium is the most common serotype of Salmonella in British pigs.  It was unknown what proportion of human STM cases are attributable to the consumption of pig-meat and whether one form of pig-meat, e.g. bacon or pork, poses a higher risk to consumers than others. Therefore, a farm-to-consumption risk assessment was developed to estimate the risk of illness from consumption of pork, bacon and sausages containing pig meat.  Also, the contribution of pig meat consumption to the overall burden of STM illness was estimated. 

Using the typical farm-to-consumption approach, the risk assessment was split into six distinct modules, each representing a separate part of the production chain.  These included Farm, Transport, Slaughter & Procsessing, Retail & storage, Preparation & Consumption and Human Effect (Dose response).  The first five modules completed the exposure assessment, where the prevalence and microbial load of STM infection/contamination of pigs and pig meat products through the production chain were estimated.  The risk was characterised by combining the exposure assessment with the hazard characterisation (Human Effect module).

Results show that the risk of illness per serving varies between pig-meat products and exposure route (cross-contamination of hands/chopping boards or ingestion of inadequately cooked pig meat).  When comparing the mean risk of illness per serving cross-contamination of hands/chopping boards from preparing pork cuts posed the greatest risk (mean risk of illness per serving 9.14*10^-7, which translates to 1 in every million servings causing illness). The lowest risk was for the consumption of inadequately cooked bacon (mean risk of illness per serving 1.8*10^-10, which is equivalent to 1 in every 5 billion servings causing illness).

The expected number of cases of STM originating from pig-meat per year was estimated from the mean risk of illness per serving for each pig-meat product by each of the two exposure routes (i.e. undercooking and cross-contamination) and the level of consumption of those products.  This suggested that approximately 30% of all STM cases are attributable to pig-meat.  However, this estimate should be treated with caution since good quality consumption data for pig-meat products was one of the data deficiencies identified by the MRA.

Veterinary Laboratories Agency, UK