DNA fingerprinting of thermophilic lactic acid bacteria using repetitive sequence-based polymerase chain reaction

DNA fingerprints of lactic acid bacteria were generated by polymerase chain reaction using a primer based on the repetitive elements found in the genome of Streptococcus pneumoniae (BOX-PCR). The method made it possible to identify 37 isolates from raw milk, industrial starters and yogurt. Differentiation at species, subspecies and strain level was possible for Lactobacillus delbrueckii subsp. lactis , Lb. delbrueckii subsp bulgaricus and Str. thermophilus . BOX-PCR was also applied to studying the strain composition of a starter culture and the direct detection of strains in commercial fermented milk.