[Long-term cryopreservation of microbial strains relevant to food hygiene]

Experiments on long-time cryopreservation at -20 degrees C were conducted, using 42 microbial strains of relevance to food hygiene. Blood slant agar was coated with 10% glycerol solution, so that all strains were in re-culturing conditions, following 12 months of storage. Re-culturing of 18 in 20 of the microbial genera used in the experiment was possible after 24 months of storage, if strains had been kept only in 10% glycerol solution. The method proved suitable particularly for strain keeping of highly sensitive genera (Lactobacillus, Pseudomonas, Aeromonas, Shigella).