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In a context of changes in food processing practices towards safer foods with fewer additives, research by UMR INRAE-Oniris SECALIM aims to generate knowledge on the influence of food processing on microbial ecology and food safety. Nitrites are additives used in charcuterie products for their contribution to the pink color but also to limit the development of pathogenic bacteria such as Clostridium. However, nitrites can lead to the formation of nitrosamines, several of which are carcinogenic, which raises a public health problem. As part of an ANR collaborative project, we investigated whether the combination of biopreservation and High Pressure (HP) could compensate for the reduction in nitrites and guarantee the microbiological quality of cooked ham. Cooked hams reduced in nitrites were contaminated by two different bacterial communities from hams. One was dominated by Pseudomonas and Serratia, the other by Psychrobacter and Vibrio. Biopreservation was applied using a strain of Lactococcus lactis selected because it produces nisin and is capable of recovering from an HP treatment of 500 MPa¹. Applied alone, none of the treatments (biopreservation or HP) can durably stabilize the microbiota of hams during storage at 8°C. Nevertheless, the combination of biopreservation and HP treatment leads to an effective stabilization of hams initially dominated by Pseudomonas and Serratia, by the proliferation of the strain of L. lactis limiting the other species. On the other hand, in hams dominated by Psychrobacter and Vibrio, the combination of treatments does not allow the complete installation of the protective strain, leaving room for Psychrobacter and the spoilage bacterium Brochothrix thermosphacta capable of recovering after the HP treatment. Thus, although promising, the effectiveness of biopreservation and HPs depends on the nature of the initial microbiota present in the ham, and requires understanding the microbial ecology of food before considering it as an alternative to the reduction of nitrite.

1. Ramaroson, M., S. Guillou, A. Rossero, S. Rezé, V. Anthoine, N. Moriceau, J.-L. Martin, F. Duranton and M. Zagorec 2018. Selection procedure of bioprotective cultures for their combined use with High Pressure Processing to control spore-forming bacteria in cooked ham. International Journal of Food Microbiology 276: 28-38. https://doi.org/10.1016/j.ijfoodmicro.2018.04.010.

Associated publication:

Chaillou, S., M. Ramaroson, G. Coeuret, A. Rossero, V. Anthoine, M. Champomier-Vergès, N. Moriceau, S. Rezé, J.-L. Martin, S. Guillou and M. Zagorec 2022. Combination of high-pressure treatment at 500 MPa and biopreservation with a Lactococcus lactis strain for lowering the bacterial growth during storage of diced cooked ham with reduced nitrite salt. Microorganisms 10(2): 456. https://doi.org/10.3390/microorganisms10020456.

Funding and partners:

This study was carried out in partnership between UMR INRAE Oniris SECALIM, Micalis Institute, UMR INRAE AgroParisTech and French Institute of Pork (IFIP) and funded under the ANR-14-CE20-0004 BLac-HP project with the support of the bioinformatic platforme INRAE MIGALE.