DOI: 10.20350/digitalcsic/17860
title: Progresion of phage infection of lactococcal dairy starters in the presence of the bacteriocin nisin or lactococcin 972 in milk [Dataset]

description: This dataset compiles the results of experiments carried out to explore the nature of putative interactions among bacteriocins and phages targeting lactococci in the context of milk fermentations. Bacteriocins, ribosomally-synthesized antimicrobial peptides involved in bacterial welfare and bacteriophages, viruses that exclusively infect bacteria, encounter frequently in the dairy environment. Previous studies performed in broth demonstrated the existence of positive bacteriocin-phage interactions (BaPI), suggesting that the presence of bacteriocins may increase the risk of a failed fermentation in the event of phage contamination. The dataset comprises measurements of the plaque size (diameter in mm) of different phages infecting distinct lactococcal strains in the presence of the bacteriocins nisin or Lcn972. The decrease of pH during fermentation of phage-contaminated milk driven by lactococci in the presence of nisin or Lcn972 is also reported. These values may be employed to calculate the percentage of inhibition (PI) compared to a control fermentation and define the nature of the interactions (positive, neutral or antagonistic).
description: File 01_plaque size_(nisin-phages) compiles plaque diameter measurements (mm) of different phages (c2, bIL170, P335, CHPC1183, p2 and sk1) infecting Lactococcus cremoris MG1363, L. cremoris MG1614, L. cremoris D1-20 or Lactococcus lactis IL1403 in the presence and absence of nisin. File 02_plaque size_(Lcn972-phage) presents plaque diameter measurements (mm) of phage sk1 infecting L. cremoris MG1614 or L. cremoris D1-20 in the presence and absence of Lcn972. File 03_pH_(Nisin-bIL170 milk fermentation) summarizes the pH evolution during milk fermentations by L. lactis IL1403 in the presence of nisin and phage bIL170, applied either individually or in combination. File 04_pH_(Lcn972_Sk1 milk fermentation) compiles pH data obtained during milk fermentations performed with several lactococcal strains, including the phage-sensitive strains L. cremoris MG1614 and L. cremoris D1-20; as well as the Lcn972-producing strain L. lactis IL1403/pBL1E and its non-producing counterpart, L. lactis IL1403. Fermentations were carried out using single strains or strain combinations, in the presence or absence of phage sk1. Each sheet corresponds to a specific experimental setup. Sheet 1 (Single strains) includes data from fermentations performed with individual strains. Sheet 2 (MG1614 combinations) contains data from the fermentation by L. cremoris MG1614 combined with L. lactis IL1403/pBL1E at different ratios. Sheet 3 (D1-20 combinations) presents data from the fermentation by L. cremoris D1-20 combined with L. lactis IL1403/pBL1E at different ratios. Sheets 4 (MG1614+phage) and 5 (D1-20+phage) compile data from fermentations carried out with L. cremoris MG1614 and L. cremoris D1-20, respectively, in the presence of different concentrations of phage sk1. Sheet 6 (MG1614 combinations + phage) includes data from the fermentation by L. cremoris MG1614 combined with L. lactis IL1403/pBL1E or L. lactis IL1403 at a 10:1 ratio in the presence of several phage sk1 concentrations. Sheet 7 (D1-20 combinations + phage) compiles analogous data or fermentations using L. cremoris D1-20 combined with L. lactis IL1403/pBL1E or L. lactis IL1403 at a 10:1 ratio, in the presence of different concentrations of phage sk1.