Debaryomyces hansenii, Proteus vulgaris, Psychrobacter sp. and Microbacterium foliorum are able to produce biogenic amines

Abstract

The occurrence of biogenic amines (BAs) produced by the microbiota of fermented foods is a source of health concern. The three bacteria Microbacterium foliorum, Proteus vulgaris and Psychrobacter sp. and the yeast Debaryomyces hansenii, isolated from surface-ripened cheeses, are known to contribute to their aromatic properties. The potential of each of these strains to produce BAs was investigated, both in pure cultures of each bacterium in a laboratory medium supplemented with amino acids and in mixed cultures with D. hansenii in a model cheese during the ripening process. BAs were quantified using HPLC. In the laboratory medium, all microbial strains produced at least one biogenic amine. P. vulgaris produced the highest amount of BAs, mainly putrescine and isoamylamine, with a total of 195 mg.L−1. In all of the model cheeses, the highest levels of BAs were determined at the end of ripening. With D. hansenii and M. foliorum, the total levels of BAs were below 10 mg.kg−1 of cheese. Gram-negative bacteria, in association with D. hansenii, produced up to 25 mg.kg−1 of BAs. Histamine was produced when Psychrobacter sp. was present, and isoamylamine, when P. vulgaris was present in the cheese ecosystem. Though these strains are able to catabolise amino acids into flavour compounds, they are also able to produce BAs, particularly putrescine, isoamylamine and histamine, showing the simultaneous expression of the two catabolic pathways. This study is a preliminary work on the assessment of the impact of all ripening microorganisms on the sanitary quality of cheese.