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Genetic diversity in Swiss cheese starter cultures assessed by pulsed field gel electrophoresis and arbitrarily primed PCR
Author(s) -
Jenkins J.K.,
Harper W.J.,
Courtney P.D.
Publication year - 2002
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.2002.01212.x
Subject(s) - starter , pulsed field gel electrophoresis , genetic diversity , gel electrophoresis , biology , polymerase chain reaction , genetics , microbiology and biotechnology , food science , genotype , gene , medicine , population , environmental health
Aims:To assess intraspecific genetic heterogeneity among commercial Swiss cheese starter culture strains ofLactobacillus helveticus,Streptococcus thermophilusandPropionibacterium freudenreichii and to compare the efficacy of two genetic typing methods. Methods and Results:Two genetic typing methods, pulsed field gel electrophoresis (PFGE) and arbitrarily primed PCR (AP‐PCR), were used. NineStrep. thermophilusstrains revealed eight PFGE and five AP‐PCR genotypes. SeventeenLactobacillusstrains yielded 16 and five genotypes by PFGE and AP‐PCR, respectively. ElevenPropionibacteriumstrains yielded 10 PFGE genotypes. Cluster analysis of PFGE profiles generated similarity coefficients forStrep. thermophilus,Lact. helveticusandProp. freudenreichiistrains of 29·5%, 60·3%, and 30·5%, respectively. Milk acidification rates forStrep. thermophilusandLact. helveticus were determined. Conclusions:Pulsed field gel electrophoresis is more discriminatory than AP‐PCR. TheLact. helveticus group is more homogeneous than the other species examined. Strains with > 87% similarity by PFGE consistently had the same acidification rate and AP‐PCR profile. Significance and Impact of the Study: Bacterial strains sold for Swiss cheese manufacture in the United States are genetically diverse. Clustering of genetically related bacteria may be useful in identifying new strains with industrially relevant traits.