Antilisterial and antistaphylococcal activity of a Lactococcus lactis strain isolated from Brazilian fresh Minas cheese

AbstractLactococcus lactis QMF 11, isolated from Brazilian fresh cheese, produces bacteriocin like inhibitory substances (bac+). To evaluateL. lactis QMF11 possible application on biopreservation systems of dairy food, co ‐inoculation studies were performed in pasteurized milk (8 °C, 10 days) targeting the inhibition ofListeria monocytogenes ATCC 7644 orStaphylococcus aureus ATCC 25923.Lactobacillus sakei ATCC 15521 was used as a negative control for bacteriocin production (bac−).L. monocytogenes andS. aureus reached 8 log CFU  ml−1 and 5.4 log CFU  ml−1 in monoculture, respectively, compared to<2.3 log CFU  ml−1 and 4.7 log CFU  ml−1 in co ‐culture withL. lactis QMF 11. Instead, in the presence of the bac−,L. monocytogenes population reached 7.3 log CFU  ml−1 andS. aureus populations 5.5 log CFU  ml−1. These results indicate thatL.lactis QMF11 may have potential for be use as biopreservative culture in dairy products, mainly because of its antilisterial activity.Practical applicationsThere is a renewed interest in the use protective bacterial cultures or their metabolites to guarantee the microbiological safety and to extend the shelf life of dairy products, in a process called biopreservation. The research in this area has been leveraged by consumers demand for naturally preserved foods. Dairy products are natural niches forLactococcus lactis strains, and these bacteria have been associated with food production and preservation since an...
Source: Journal of Food Safety - Category: Food Science Authors: Tags: Original Article Source Type: research