Enterococcus faecium: a promising protective culture to control growth of ochratoxigenic moulds and mycotoxin production in dry-fermented sausages

Moulds positively contribute to the development of typical characteristic flavour and aroma of dry-fermented sausages. However, some mould species, such as Penicillium nordicum and Penicillium verrucosum, may contaminate this product with ochratoxin A (OTA). For this reason, the control of toxigenic moulds is needed. Strategies based on the use of antifungal microorganisms present in the native microbial population in the dry-fermented sausage processing could be a promising strategy. The aim of this work was to study the effect of Enterococcus faecium strains on P. nordicum and P. verrucosum growth and OTA production in a dry-fermented sausage-based medium at conditions of temperature and water activity similar to those occurring during the ripening of these meat products. Six strains were screened to evaluate their growth capacity and antifungal activity against P. nordicum and P. verrucosum at three fixed temperatures related to the sausage ripening. The two E. faecium strains that decreased growth of both species were chosen to further evaluate their effect on growth of P. verrucosum and P. nordicum and their mycotoxin production under conditions simulating the dry-fermented sausage ripening. The presence of E. faecium SE920 significantly reduced OTA production of P. nordicum although it did not affect P. verrucosum. E. faecium SE920, isolated from dry-fermented sausages, could be a good candidate to reduce OTA production by P. nordicum in dry-fermented sausages.