Quantitative Risk Assessment for Salmonella in Lettuce (Lactuca sativa) Consumed in Benin, West Africa

The present study aims at quantitatively assessing the risk associated with Salmonella in lettuce (Lactuca sativa) consumed in Benin (West Africa). To that end, a survey was conducted involving 550 respondents to determine the conditions under which the product is handled along the supply chain and its consumption pattern. The prevalence and concentration of Salmonella in lettuce were collected from the literature. The consumption data and the data on Salmonella concentrations in lettuce were combined to estimate the exposure to Salmonella using a probabilistic risk assessment method. The @Risk software package (Palisade USA) was used to run Monte Carlo simulations with 10,000 iterations. Three dose-response models were used to assess the risk of salmonellosis. Different scenarios were tested to identify factors that could influence the risk of salmonellosis. The results showed that lettuce is exposed to temperature abuse under inappropriate hygienic conditions. In 90% of the cases, the exposure to Salmonella was between 3 and 7 log CFU/serving. The risk of salmonellosis per serving varied from 7.7% to 95% depending on the dose-response used with the scenario taking into account the current handling conditions of the lettuce. In contrast, when considering the scenario where the cold chain is respected along the supply chain, the risk of salmonellosis varied from 0% to 3.3% depending on the dose response used. The study highlights the importance of the cold chain, good agricultural practices and good hygienic practices to reduce exposure to Salmonella through the consumption of lettuce and thus the risk of salmonellosis.