Impact of Lactobacillus curvatus 54M16 on microbiota composition and growth of Listeria monocytogenes in fermented sausages.

Lactobacillus curvatus 54M16 produced bacteriocins sak X, sak Tα , sak Tβ and sak P. The aim of this study was to investigate the anti-listerial activity of the bacteriocins-producing strain against Listeria monocytogenes in vitro co-culture experiments and during the manufacture of fermented sausages. In MRS broth, Lb. curvatus 54M16 was able to inhibit L. monocytogenes to undetectable levels after 48 h at 20 °C or 5 days at 15 °C. Anti-listerial activity was lower during the production of fermented sausages with pathogen inoculation at levels of approximately 4 Log CFU g-1 . However, total inhibition of L. monocytogenes native to the raw ingredients was achieved over the course of the fermentation. Moreover, 16S rRNA-based analysis revealed the ability of Lb. curvatus 54M16 to dominate and affect the bacterial ecosystem, whereas spoilage-associated bacterial genera, such as Brochothrix, Psychrobacter, Pseudomonas and some Enterobacteriaceae, were found until the end of ripening in sausages without Lb. curvatus 54M16. The use of the bacteriocins-producing Lb. curvatus 54M16 in fermented sausages could be an important contribution to product safety, provided that eco-physiological factors and other preservation methods are maintained at levels required for the inhibition of pathogens in controlled conditions.