Use of a bacteriocin-producing transconjugant as starter in acceleration of cheese ripening

The non-conjugative 46 kb plasmid that encodes the biosynthesis of lacticin 3147 in Lactococcus lactis IFPL105 has been transferred to the starter L. lactis IFPL359, used in goatʹs milk cheesemaking. The accelerating effect exerted on proteolysis and development of sensory characteristics of semi-hard cheese by the bacteriocin-producing transconjugant L. lactis IFPL3593 (Lac+ Bac+ Imm+), which is able to induce cell lysis in starter adjuncts with high peptidase activity, has been studied. It has been demonstrated that the use of IFPL3593 as starter accelerates cheese ripening as it increases the level of amino nitrogen correlated with early cell lysis of adjuncts. The fact that the bacteriocin-producing microorganism used is immune to the bacteriocin, allowed proper acidification of the curd without altering the cheese-making process.