Effect of a nisin‐producing lactococcal starter on the late blowing defect of cheese caused by <i>Clostridium tyrobutyricum</i>
Marta Ávila, Natalia Gómez‐Torres, Pilar Gaya, Sonia Garde
Abstract
Summary Clostridium tyrobutyricum causes swelling, cracks and off‐flavours of cheeses (late blowing defect, LBD) due to butyric acid fermentation. To control this spoilage bacterium, we investigated the use of nisinogenic Lactococcus lactis subsp. lactis INIA 415 as starter in cheeses contaminated with C. tyrobutyricum spores. Control cheese made with spores showed LBD after 14 days of ripening. However, in cheese made with the bacteriocin producer and spores, in which (unlike control cheese) bacteriocin activity was detected throughout ripening, LBD occurred after 21 days. At this stage, level of lactic acid was 1.22‐fold higher ( P < 0.01) and concentrations of propionic and butyric acids were 2.15‐ and 2.32‐fold, respectively, lower ( P < 0.01) in cheese made with the nisin producer than in control cheese, according to the less pronounced spoilage symptoms showed by the former cheese. The bacteriocin producer delayed the appearance of LBD, although it cannot arrest completely C. tyrobutyricum growth.