Predicting the risk of Listeria monocytogenes outgrowth, especially for ready-to-eat foods and drinks

Listeria is a constant concern for the food industry and for regulators, as it can cause the serious illness listeriosis. While this pathogen is inactivated by heating, there is still a risk that it can contaminate a finished product post-processing, for instance upon contact with processing equipment, transportation belts, or during slicing, filling, packaging, etc. It is critical to understand whether and how the food product you are developing can support the growth of Listeria – especially for ready-to-eat products that are generally not heated before consumption. The microbiological criteria for release are very strict for ready-to-eat products, but even more so when the product can support Listeria monocytogenes growth.

In addition, when L. monocytogenes is encountered in production environments, it is crucial to tailor your preventive measures to the specific sub-species. NIZO can characterise sub-species with the highest level of resolution.

Designing safety into your product and processes

By modelling the inactivation and growth of Listeria monocytogenes, NIZO can determine whether the product you are developing is at risk to support the growth of the pathogen – before you finalise your process and formulation. And we can validate your Listeria bio-protection system to ensure that it is robust enough to meet market requirements.

Modelling Listeria survivability in cheese

Assess the microbial safety of your cheese through our lactic acid calculation model! Use our model to evaluate the microbial safety of your cheese product. The model calculates the amount of undissociated lactic acid against the cut-off value for inhibition of L. monocytogenesThe outcome states if your cheese is inherently safe or not, based only on its lactic acid content.

NIZO can help you to make your product safer

  • Model potential Listeria outgrowth in your product, and assess the risk 
  • Evaluate your Listeria control strategies, including your bio-protection systems 
  • Provide knowledge-based advice on formulations and processes to minimise risk 

Any questions?

Martin Ham is happy to answer all your questions.

Meet Martin Ham