Bacterial role in flavour development.

The role of bacteria in the production of non volatile and volatile compounds involved in the fermented meat flavour is discussed. Lactic acid bacteria produce D-lactic and acetic acids which may give a sour note. By reducing the pH, they also modulate the other bio-chemical bacterial activities. In muscle tissue proteins are degraded into peptides and lipids into fatty acids mainly by endogenous enzymes. In fermented meat products with a high pH lipases from very lipolytic species of Staphylococcus could increase lipolysis. Bacteria could also play a role in the production and degradation of free amino acids. Staphylococcus and to a lesser extent, lactic acid bacteria could participate in the production of methyl-branched aldehydes and their corresponding alcohols and acids from branchedchain amino acids. By their nitrate reductase and catalase Staphylococcus species limit fatty acid oxidation and aldehyde production. Staphylococcus could contribute to the ester content as they can produce or hydrolyse esters in vitro.