A Strange Spoilage in Goose Sausages and <em>Levilactobacillus Brevis</em>, Mould and Enterococci Are the Responsible

Abstract

The aim of this work was to investigate the microorganisms and their metabolites responsible for the spoilage of goose sausages produced in a small facility in Lombardy, a northern region of Italy. Spoilage was first detected by sensorial analysis using the “needle probing” technique; however, the spoiled sausages were not marketable due to the high ammonia and vinegar smell. The added starter culture did not limit or inhibit the spoilage microorganisms, which were represented by Levilactobacillus brevis, the predominant species, and by Enterococcus faecalis and E. faecium. These microorganisms grew during ripening and produced a large amount of biogenic amines, which could represent a risk for consumers. Furthermore, Lev. brevis, being a heterofermentant, also produced ethanol, acetic acid and a variation in the sausage colour. The production of biogenic amines was confirmed in vitro. Furthermore, as observed in a previous work, a second cause of spoilage can be attributed to moulds that grew during ripening; both the isolated strains, Penicillium nalgiovense, added as starter culture, and P. lanoso-coeruleum, present as environmental contaminant, grew between the meat and casing, producing a large amount of total volatile nitrogen, responsible for the ammonia smell perceived either in the ripening area or in the sausages. This is the first description of Levilactobacillus brevis predominance in spoiled goose sausage.