Enhancement of Proteolysis by a Lactococcus lactis Bacteriocin Producer in a Cheese Model System

The accelerating effect exerted on proteolysis in cheese−curd slurries by the bacteriocin producer Lactococcus lactis IFPL 105, which is able to induce cell lysis in starter adjuncts with high peptidase activity, Lactobacillus casei subsp. casei IFPL731, and Lactococcus lactis subsp. lactis T1 has been studied. The optimum conditions for the use of the bacteriocin producer have been investigated to avoid late acidification by the starter and promote early cell lysis with the subsequent release of the intracellular peptidases and the acceleration of ripening without altering the cheese-making process. The induced cell lysis was of special importance in the case of Lc. lactis T1, because this strain possesses high peptidase activity and therefore can greatly influence the development of cheese flavor when added as an adjunct starter. In this study, it has been found that addition of Lc. lactis IFPL 105 does not interfere with proper acidification of the curd by the starter and increases the level of amino nitrogen correlated with early lysis of adjuncts, owing to the presence of bacteriocin. Keywords: Bacteriocin; lysis; proteolysis