**5. Phage sensitivity of LAB starters used in dairy industry**

Virulent phages of *Lactococcus lactis* spp. are the most frequently encountered phages in milk plants during cheese and dairy beverages production. Additionally, phages attacking *Streptococcus thermophilus* are often observed in cheese and less distinct in yoghurt manufacturing. Phages against *Lactobacillus* spp. and *Leuconostoc* spp. starter cultures represent a minor problem [23]. Currently, in production of dairy beverages functional *Lactococcus* and *Streptococcus thermophilus* texturizing strains with ability to produce exopolysaccharides (EPS) are commonly used. In nature it is very difficult to find strains with similar rheological properties differing in resistance to phages. Thus, phage contamination of texturizing strains can lead to serious problems in ensuring quality dairy products.
