Non-starter LAB

Amino acid degradation is important for the synthesis of volatile compounds and the transamination of some amino acids methionine, branched-chain, and aromatic amino acids. Transamination is the main degradation pathway that leads to the formation of a-keto acids, which are then degraded into various aromatic compounds. The conversion of amino acids to keto- and hydroxyl acids is initiated by lactobacilli, and Lactococcus strains further convert these products to carboxylic acid. This cooperation between LAB and non-starter LAB can enhance cheese flavor. 

Biotic factors also modulate the expression of the flavor-related activities of LAB. Microbial interactions, which can be beneficial (cooperation), neutral or adverse (inhibition), determine the succession of microbial communities in fomented foods (Pelaez and Requena 2005 Irlinger and Mounier 2009). Interactions occur within the strains and species of the LAB starter, between starto-and non-starter LAB (Martley and Crow 1993 Grappin et al. 1999 Crow et al. 2001), and between LAB and other microbial groups (Narvhus and Gadaga 2003). Microbial interactions can also impact cell death. As an example, the lysis of strains of Lact. helveticus in Swiss cheeses induces a concomitant lysis of Strep, thermophilus (Deutsch et al. 2002)... 

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