Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 3Citation - Scopus: 5Production of Food Grade Ss-Galactosidase From Artisanal Yogurt Strains(Taylor and Francis Ltd., 2010) Tarı, Canan; Üstok, Fatma Işık; Harsa, ŞebnemSuperior artisanal isolates of thermophilic lactic acid bacteria producing high lactic acid and β-galactosidase were isolated from traditional Turkish yogurt samples from the Toros mountain region from a highly bio-diverse environment. A full factorial statistical design, with the factors of types of strains and medium formulations under static and agitation conditions, were applied to investigate the effects on β-galactosidase and lactic acid production. Streptococcus thermophilus 95/2 and Lactobacillus delbrueckii subsp. thermophilus 77 exhibited remarkable potential as promising starter culture candidates valuable to various applications in the dairy industry. The efficiency of cell disruption methods was investigated on the extraction of intracellular β-galactosidase enzyme. Lysozyme enzyme treatment was determined as the most effective method, which resulted in approximately 1.5 and 10 times higher enzyme activity than glass bead and homogenization treatment, respectively. © Taylor & Francis Group, LLC.Article Citation - WoS: 39Citation - Scopus: 49Prevalence and Antibiotic Resistance of Foodborne Staphylococcus Aureus Isolates in Turkey(Mary Ann Liebert Inc., 2011) Aydın, Ali; Muratoğlu, Karlo; Sudağıdan, Mert; Bostan, Kamil; Okuklu, Burcu; Harsa, ŞebnemIn this study, 154 Staphylococcus aureus isolates were detected from 1070 food samples (14.4%) collected from seven cities in Turkey. Antimicrobial susceptibility testing against 21 antibiotics was performed by agar disk diffusion method, and those isolates resistant to any antibiotic were further analyzed to determine minimum inhibitory concentration by E-test and polymerase chain reaction analysis of vanA and mecA genes. According to disk diffusion test results, a total of 139 strains were resistant to at least one tested antibiotic, with 39 (25.3%) strains being multidrug resistant (MDR) and the other 15 strains being susceptible to all antibiotics. Penicillin G, linezolid, erythromycin, and tetracycline took up 71.4%, 23.4%, 18.2%, and 15.6% of the tested strains, respectively. In addition, all of the strains were susceptible to vancomycin, oxacillin, cefoxitin, and imipenem. Only one strain (S158B) was resistant to both teicoplanin and cefazolin. On the other hand, the presence of vanA and mecA genes was not detected in the strains. Pulsed-field gel electrophoresis analysis was used to identify genetic-relatedness of the MDR strains. It is noteworthy that some strains from different sources showed 100% homology; however, some of MDR strains were found unrelated with 60% or less homology. The high diversity observed in pulsed-field gel electrophoresis results indicated the possible contamination of S. aureus from different sources and routes.