Isolation and Identification of Listeria spp. from White Cheese Samples Presented for Consumption in Istanbul

Abstract

In this study, 119 feta cheese samples taken from different vendors in Istanbul were examined for the presence of Listeria monocytogenes. Isolates were confirmed by the PCR method using iap and hlyA primers, and the antibiotic susceptibility of the identified strains was performed by the Kirby-Bauer protocol. Seven Listeria spp. were isolated from three (2.52%) of 119 cheese samples analyzed. The seven Listeria spp. obtained from these three samples were found to contain the iap gene region but not the hlyA gene region. As a result of the sequence analysis using the 16S rRNA gene region, it was determined that these isolates were L. seeligeri. As a result of antibiotic susceptibility tests, it was observed that L. seeligeri isolates showed ciprofloxacin (85.71%) and penicillin (42.85%) resistance. All strains were susceptible to amikacin, amoxicillin/clavulanic acid, chloramphenicol, rifampin, gentamicin, cefaclor, ampicillin, trimethoprim-sulfamethoxazole, tetracycline, vancomycin, and clarithromycin antibiotics. The detection of Listeria spp. isolates in feta cheese samples made with pasteurized milk revealed that packaging, distribution, and storage practices following the pasteurization process should be followed more strictly. It is recommended to apply controls at each stage to prevent contamination.

Preliminary study on antimicrobial activities of skin mucus fromby-catch of Elasmobranch species

“…Amplification was performed as was carried out in Thermal Cycler (Bio-Rad, USA) and programmed at 60 s initial denaturation at 95°C, 30 cycles of denaturation at 95°C for 15 s, annealing for 15 s at 53°C, and extension for 10 s at 72°C. The BLAST analyses of 16S rRNA sequences were obtained by using the National Centre for Biotechnology Information (NCBI) database (Kaya et al 2021).…”