Bacteriocin‐phage interaction (BaPI): Phage predation of Lactococcus in the presence of bacteriocins

Abstract

Bacteriophages infecting dairy starter bacteria are a leading cause of milk fermentation failure and strategies to reduce the risk of phage infection in dairy settings are demanded. Along with dairy starters, bacteriocin producers (protective cultures) or the direct addition of bacteriocins as biopreservatives may be applied in food to extend shelf‐life. In this work, we have studied the progress of infection of Lactococcus cremoris MG1363 by the phage sk1, in the presence of three bacteriocins with different modes of action: nisin, lactococcin A (LcnA), and lactococcin 972 (Lcn972). We aimed to reveal putative bacteriocin‐phage interactions (BaPI) that could be detrimental and increase the risk of fermentation failure due to phages. Based on infections in broth and solid media, a synergistic effect was observed with Lcn972. This positive sk1‐Lcn972 interaction could be correlated with an increased burst size. sk1‐Lcn972 BaPI occurred independently of a functional SOS and cell envelope stress response but was lost in the absence of the major autolysin AcmA. Furthermore, BaPI was not exclusive to the sk1‐Lcn972 pairing and could be observed with other phages and lactococcal strains. Therefore, bacteriocins may facilitate phage predation of dairy lactococci and their use should be carefully evaluated.

The Impact of HPP-Assisted Biocontrol Approach on the Bacterial Communities’ Dynamics and Quality Parameters of a Fermented Meat Sausage Model

“…In particular, HPP, bacteriophages, and bacteriocinogenic lactic acid bacteria (LAB) have recently been explored as innovative hurdles applied in the multi-hurdle technology concept. Although positive interactions between phages and bacteriocinogenic LAB for a bactericidal effect on a target pathogen have been documented, bacterial regrowth still occurs in biocontrol carried out under atmospheric conditions [ 8 , 9 ]. High hydrostatic pressure (HHP) is a well-established non-thermal technology in which a packaged food product is immersed in a pressurized fluid, such as water, at pressures up to 600 MPa, which promotes microbial inactivation by disrupting cellular integrity [ 10 ].…”