Lactic acid bacteria decarboxylation reactions in cheese

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.