Inactivation of Listeria monocytogenes during dry-cured ham processing

The effect of Serrano and Iberian dry-cured ham processing and ripening on Listeria monocytogenes inactivation at the surface of whole hams was investigated. Salted hams were surface inoculated (6.5 log CFU) with a cocktail of 4 L. monocytogenes strains isolated from environment and products of a meat industry. Serrano and Iberian hams were ripened for 16 and 24 months, respectively. A decrease of at least 4.6 log units on the surface of Serrano ham was recorded after 4 months for L. monocytogenes counts, which remained under the detection limit thereafter. L. monocytogenes declined by >5 log units on the surface of Iberian ham during the first 9 months and was not detected afterwards. The higher nitrite content of Serrano ham might have accelerated the decrease of the pathogen. This study validates the inactivation of L. monocytogenes on the surface of whole dry-hams during extended ripening. •L. monocytogenes declined by >4.6 logs on Serrano ham after 4 months.•L. monocytogenes declined by 5.4 logs on Iberian ham after 9 months.•The higher nitrite content of Serrano ham might have accelerated the decrease.•Ham processing was highly effective in inactivating L. monocytogenes during ripening.