HOW THE COLD CHAIN IMPACTS THE SHELF LIFE OF A READY-TO-EAT FOOD REGARDING LISTERIA MONOCYTOGENES

摘要

For RTE foods that are able to support the growth of L. monocytogenes, a European Regulation (n°2073/2005) specifies that the 100-CFU/g limit "applies if the manufacturer is able to demonstrate that the product will not exceed the limit of 100 CFU/g throughout the shelf-life". Many factors can interfere on the evolution of the pathogen (time-temperature history, pH, aw, associated microflora…). The objective of this work was to demonstrate the impact of the cold chain on the shelf-life of a deli meat, sliced cooked ham. Sliced cooked ham data were obtained from challenge-tests with artificially inoculated packages with L. monocytogenes. These data are useful for estimating growth parameters and model validation. We tested different scenarios of storage temperature: from theoretical to more realistic scenarios based on data from a survey carried out in France. The variability of temperatures as well as characteristics of the product, and initial contamination level at the end of the manufacturing line, were taken into account in predictive models to calculate the time to reach the regulatory limit and to determine the shelf life. We showed that shelf-life determination is strongly dependant of the scenario chosen to simulate the cold chain.