Biocontrol of ochratoxigenic Penicillium nordicum in dry-cured fermented sausages by Debaryomyces hansenii and Staphylococcus xylosus.

Penicillium nordicum is the main ochratoxin A (OTA) producing mould in dry-cured meat products. The use of autochthonous microorganisms as protective cultures is a promising strategy to control this hazard. The aim of this work was to evaluate the effect of Debaryomyces hansenii and Staphylococcus xylosus isolated from dry-cured meat products as biocontrol agents (BCAs) against P. nordicum during the ripening of dry-cured fermented sausages. The BCAs were added to the dough, and P. nordicum were inoculated on the surface after stuffing. Then, the sausages were ripened following a traditional processing. The growth of the microorganisms was determined by plate count at the beginning and at the end of ripening. To assess the implantation of BCAs in the sausages, the yeasts and staphylococci isolated from the sausages at the end of processing were identified by sequencing the 16S and 18S rRNA respectively, and they were characterized by pulsed field gel electrophoresis (PFGE) of the chromosomal DNA. OTA was quantified by UHPLC-MS/MS. BCAs were able to colonise and develop throughout the processing. Although none of the BCAs reduced the growth of P. nordicum, a OTA decrease was observed in the sausages inoculated with D. hansenii individually or combined with S. xylosus. The drop of OTA amount was particularly marked in the portions where the casing was damaged allowing the mould to grow inside the sausages. In these areas, OTA was not detected in the inoculated batches. In conclusion, D. hansenii could be proposed as BCA individually or in combination with S. xylosus for the biocontrol of OTA hazard in dry-cured fermented sausages.