Listeriosis risk assessment: Simulation modelling and “what if” scenarios applied to consumption of ready-to-eat products in a Spanish population

A one dimensional model was developed to assess the risk of listeriosis in Navarra (Spain) due to the consumption of smoked fish (salmon and trout) and sliced cooked ham (vacuum or non-vacuum-packed). Data regarding serving size, proportion of consumers, time of storage, refrigerator temperature, prevalence and counts of Listeria monocytogenes were loaded into the model in order to describe the variability, using Monte Carlo simulation. The final output of the model was the estimation of the annual number of listeriosis cases, the consumption of cooked ham being the responsible for the higher prediction of cases. Different “what if” scenarios have been studied in order to assess the likely impact of strategies in the estimated cases. Temperature storage at 4 °C through the food chain (including storage at home) has been demonstrated to be the best tool to decrease the risk of this serious illness.