Accelerated cheese ripening: use of Lac−mutants of lactococci

Summary Lactose-negative mutants ofLactococcus lactissubsp.lactisandLacto-coccus lactissubsp.cremoriswith good autolytic properties were used at two different levels in addition to the normal starter in Gouda-type cheesemaking experiments. Increased numbers of bacteria were observed in fresh cheese, and the pH changes during ripening were as normal. A more rapid development of soluble N compounds was observed in cheeses with mutant addition, especially withLc. lactissubsp.lactisIMN-L2–3 andLc.lactissubsp.cremorisIMN-C12–1, compared with the control cheese. Cheese with addedLc. lactissubsp.lactisIMN-L2–3 andLc.lactissubsp.cremorisIMN-C12–1 showed the most extensive ripening and the highest product quality of the mutants tested. The experimental cheeses were graded higher than the control cheese. The ripening time was significantly reduced, and the quality was retained at an acceptable level during storage.