Risk assessment of Salmonella in Danish meatballs produced in the catering sector

• A modular process model was applied to estimate salmonellosis risk from meatballs.
• Data from observational studies in the Danish catering were successfully included.
• Scenario and sensitivity analyses were used to test the impact of critical steps.
• Temperatures higher than 70 °C had an important impact on the reduction of the risk.
• Prevalence and concentration impacted salmonellosis risk estimates the most.

A modular process risk model approach was used to assess health risks associated with Salmonella spp. after consumption of the Danish meatball product (frikadeller) produced with fresh pork in a catering unit. Meatball production and consumption were described as a series of processes (modules), starting from 1.3 kg meat pieces through conversion to 70 g meatballs, followed by a dose response model to assess the risk of illness from consumption of these meatballs. Changes in bacterial prevalence, concentration, and unit size were modelled within each module. The risk assessment was built using observational data and models that were specific for Salmonella spp. in meatballs produced in the catering sector. Danish meatballs are often pan-fried followed by baking in an oven before consumption, in order to reach the core temperature of 75 °C recommended by the Danish Food Safety Authority. However, in practice this terminal heat treatment in the oven may be accidentally omitted. Eleven production scenarios were evaluated with the model, to test the impact of heat treatments and cooling rates at different room temperatures. The risk estimates revealed that a process comprising heat treatment of meatballs to core temperatures higher than 70 °C, and subsequent holding at room temperatures lower than 20 °C, for no longer than 3.5 h, were very effective in Salmonella control. The current Danish Food Safety Authority recommendation of cooking to an internal temperature of 75 °C is conservative, at least with respect to Salmonella risk. Survival and growth of Salmonella during cooling of meatballs not heat treated in oven had a significant impact on the risk estimates, and therefore, cooling should be considered a critical step during meatball processing.