*3.7.1 Isolation from cheese sample*

Ward and Timmins [110] published another investigation which found that three strains isolated from cheese samples having *Lactobacillus casei, Lactobacillus paracasei* and *Lactobacillus rhamnosus* were distinguished by PCR. In MRS agar samples, 63 isolates were cultivated and evaluated with sugar fermentation phenotypes. These isolates then belonged to the casei group. PCR primers were developed for 16S rRNA gene preserved areas and particular fragments were amplified with PCR. The agarose gel separated the amplified products from the data base and retrieved their gene sequences. These three distinct strains in the region VI of 16S rRNA have given unique amplified products. At the end of the process, a product containing the 16S rRNA *Lt. paracasei* gene was discovered in 51 of 63 isolates and a product containing the 16S rRNA gene *L rhamnosus* was given in 12 of 63 by primers, whereas a product containing the *L. casei* primers was not detected.
