Fermentation in cheese comprises oxidation-reduction of carbohydrates to yield organic acids, alcohols
and carbon dioxide. Furthermore, organic acid and amino acid metabolism produces a series of compounds
that positively or negatively affect final cheese quality. Under the strong selective pressure of the
acidic environment of cheese ripening, lactic acid bacteria have developed multiple stress-resistant
strategies, including decarboxylase and deiminase reactions that play a main physiological role during
the ripening process of cheese production. The control of the expression and activity of these enzymes is
one active strategy for intracellular acid-base homeostasis. This review covers relevant pathways and
aspects related to gene regulation of gene clusters present in starter or non-starter lactic acid bacteria
that are involved in sensory changes such as flavour development. From the point of view of food safety
the main decarboxylation pathways that lead to the formation of biogenic amines are described