Combined effect of natural antimicrobials and high pressure processing to prevent Listeria monocytogenes growth after a cold chain break during storage of cooked ham

The effect of high pressure processing (400 MPa for 10 min) and natural antimicrobials (enterocins and lactate–diacetate) on the behaviour of Listeria monocytogenes in sliced cooked ham during refrigerated storage (1 °C and 6 °C) was assessed. The efficiency of the treatments after a cold chain break was evaluated. Lactate–diacetate exerted a bacteriostatic effect against L. monocytogenes during the whole storage period (three months) at 1 °C and 6 °C, even after temperature abuse. The combination of low storage temperature (1 °C), high pressure processing (HPP) and addition of lactate–diacetate reduced the levels of L. monocytogenes during storage by 2.7 log CFU/g. The most effective treatment was the combination of HPP, enterocins and refrigeration at 1 °C, which reduced the population of the pathogen to final counts of 4 MPN/g after three months of storage, even after the cold chain break.