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High Pressure (HP) (cold pasteurization) and biopreservation (addition of lactic ferments) are two food preservation technologies. These treatments, applied in isolation, are ineffective against the spores produced by certain bacteria known as sporulating. In contrast, HPs are able to induce the germination process, which transforms spores into so-called vegetative cells that can be controlled by biopreservation.
The objective of this study was therefore to combine HP and biopreservation to control sporulating bacteria (and their spores), naturally present in cooked ham and interfering with its preservation. Lactic acid bacteria were therefore selected on the basis of their antagonistic properties with respect to sporulating bacteria and their resistance to HP treatment.
From a collection of 63 strains of lactic acid bacteria of various origins, 14 strains were first selected according to safety and innocuity criteria. The antagonistic effect of these strains, against sporulating species of Bacillus and Clostridium, made it possible to retain a strain of Lactobacillus curvatus and a strain of Lactococcus lactis. Their resistance and their ability to grow, after the application of an HP treatment, were then characterized.
Although the strain of L. curvatus was found to be the most resistant to HP, only the strain of L. lactis demonstrated the ability to grow after treatment was applied. For this reason and after verifying the absence of biogenic amines produced in ham, toxic to varying degrees, this strain was considered the best candidate to develop a new treatment combining HP and biopreservation in cooked ham.

Partners : This work was carried out in the framework of the ANR BLac-HP project (ANR-14-CE20-0004) with 10 partners including UMR SECALIM and MICALIS