Impact of intervention strategies on listeriosis risk in cooked ham: Biopreservation and high pressure processing

Biopreservation and post-lethality treatments (PLT) are the basis of operating procedures applied to reduce the levels of Listeria monocytogenes in ready-to-eat food. The combination of these strategies must be wisely selected, and their interaction should be considered in quantitative microbial risk assessments (QMRA) assessing the listeriosis risk. The aim of the present study was to develop a QMRA model to assess the impact of intervention strategies, including formulation with lactate, bioprotective cultures and the use of high-pressure processing (HPP), on reducing the listeriosis risk associated to the consumption of cooked meat products by elderly populations. Particularly, the interaction between the formulation with lactate and the application of HPP was addressed as lactate is reported to exert (i) a piezo-protection on L. monocytogenes inactivation by HPP and (ii) a piezo-stimulation effect on the growth rate of survivors. Results showed that the reduction of product's shelf-life or the use of biopreservation strategies (lactate and bioprotective cultures) were more effective in reducing the listeriosis risk than mild HPP treatments. Moreover, the application of a mild HPP treatment in combination with the formulation with lactate did not result in a higher risk reduction compared to the formulation of lactate alone. On the other hand, the application of a 5-log PLT was more effective for risk reduction compared to other strategies. The results provided in this work can help in the design of measures to control L. monocytogenes that have the desired impact on risk of reduction.