Biodiversity of Lactobacillus helveticus bacteriophages isolated from cheese whey starters

Twenty-one Lactobacillus helveticus bacteriophages, 18 isolated from different cheese whey starters and three from CNRZ collection, were phenotypically and genetically characterised. A biodiversity between phages was evidenced both by host range and molecular (RAPD-PCR) typing. A more detailed characterisation of six phages showed similar structural protein profiles and a relevant genetic biodiversity, as shown by restriction enzyme analysis of total DNA. Latent period, burst time and burst size data evidenced that phages were active and virulent. Overall, data highlighted the biodiversity of Lb. helveticus phages isolated from cheese whey starters, which were confirmed to be one of the most common phage contamination source in dairy factories. More research is required to further unravel the ecological role of Lb. helveticus phages and to evaluate their impact on the dairy fermentation processes where whey starter cultures are used.