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

Abstract

Lactococcus lactis QMF 11, isolated from Brazilian fresh cheese, produces bacteriocin like inhibitory substances (bac+). To evaluate L. 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 of Listeria monocytogenes ATCC 7644 or Staphylococcus aureus ATCC 25923. Lactobacillus sakei ATCC 15521 was used as a negative control for bacteriocin production (bac−). L. monocytogenes and S. 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 with L. lactis QMF 11. Instead, in the presence of the bac−, L. monocytogenes population reached 7.3 log CFU ml−1 and S. aureus populations 5.5 log CFU ml−1. These results indicate that L. lactis QMF11 may have potential for be use as biopreservative culture in dairy products, mainly because of its antilisterial activity. Practical applications There 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 for Lactococcus lactis strains, and these bacteria have been associated with food production and preservation since ancient times. As a dominant species in dairy ecosystems, L. lactis strains are very interesting because they are not likely to require regulatory approval for practical application as bioprotective cultures.

Revealing the microbial heritage of traditional Brazilian cheeses through metagenomics

“…S4). Further analysis such as strain isolation and genome sequencing will be valuable in providing more information about specific genes and should pave the way for technological studies focused on the use of these strains, as biopreservatives, for example, as was shown with the L. lactis strain QMF11 isolated from a Brazilian cheese, which has strong anti-listerial activity (Costa et al, 2018).…”

Bacteriocins Produced by LAB Isolated from Cheeses within the Period 2009–2021: a Review

“…Pediococcus pentosaceus was isolated from ripened Minas cheese, an artisanal cheese made with raw cow's milk, detecting the presence of the pediocin PA-1 gene in the LAB isolated [40]. Cabral Carvalhaes Costa et al [41] isolated L. lactis QMF11 from fresh Minas cheese. Two strains of Lactobacillus plantarum, LCN 17 and LCN 43, were isolated from artisanal ewe's cheese from Rio Grande do Sul [42].…”