FIELD: medicine.
SUBSTANCE: invention refers to a method of producing a mutant lactobacillus Streptococcus thermophilus, to a milk ferment, a method of producing a fermented milk product and to the fermented milk product. The offered invention can be used for producing the fermented milk products with improved storage characteristics. A method of producing the mutant lactobacillus Streptococcus thermophilus characterised by weaker postoxidation, than a parent strain is implemented by introducing in DNA a genome of said parent strain of mutation codon 552 coding histidine, of teh domain HA of lactose permease. Said mutation induces replacement of said histidine by amino acid which is distinct from serine, tyrosine, histidine and threonine.
EFFECT: invention allows producing the mutant lactobacillus Streptococcus thermophilus characterised by weaker postoxidation and suitable particularly for producing the fermented milk products.
10 cl, 5 dwg, 3 tbl, 2 ex
