Progresion of phage infection of lactococcal dairy starters in the presence of the bacteriocin nisin or lactococcin 972 in milk [Dataset]

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).