Biogenic amine production and degradation profiles of selected cheese isolates in cheese-derived model ecosystems

Biogenic amines (BA) are nitrogenous compounds commonly accumulated in cheeses as a consequence of microbial amino acid decarboxylation. Although the ability to produce or degrade BA is generally considered strain-dependent, the actual contribution of cheese environmental conditions in shaping microbial metabolism remains poorly understood. In this study, microorganisms isolated from different cheeses were screened for their ability to produce or degrade BA in chemically defined media. Four BA-producing isolates, namely PWC (Weissella cibaria), PLP (Lactiplantibacillus plantarum), PEF (Enterococcus faecium), and PEH (Enterobacter hormaechei), together with two BA-degrading isolates, DLP (Lactiplantibacillus plantarum) and DLF (Limosilactobacillus fermentum), were selected and cultivated in three cheese broth media prepared from long-ripened grana cheeses, medium-ripened pecorino cheeses, and surface-ripened cheeses. The cheese broths differed markedly in buffering capacity, peptide composition, precursor amino acid (PAA) availability, and endogenous BA content, despite showing similar initial pH values. No residual lactose or glucose was detected in the media, suggesting that microbial metabolism mainly relied on nitrogen compounds and amino acid catabolism. After incubation, distinct metabolic responses were observed depending on the cheese matrix. Long-ripened grana cheese broth promoted proteolysis and amino acid accumulation, whereas medium-ripened pecorino and surface-ripened cheese broths favoured BA accumulation, particularly tyramine, putrescine, and cadaverine. Multivariate analysis showed that sample clustering was mainly driven by cheese broth composition rather than by microbial taxonomy or preliminary in vitro phenotype. Overall, the results indicate that environmental and physicochemical characteristics of cheese matrices, especially buffering capacity and availability of peptides and PAA, strongly modulate microbial BA metabolism and may override strain-specific metabolic traits.