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    Clonal diversity and antifungal susceptibility of Candida spp. recovered from cow milk
    (Croatian Dairy Union, 2020) Hizlisoy, Harun; Onmaz, Nurhan Ertas; Al, Serhat; Karadal, Fulden; Yildirim, Yeliz; Gonulalan, Zafer; Gumussoy, K. Semih
    The aim of this study was the isolation, identification, phylogenetic analysis and antifungal susceptibility of Candida spp. from milk samples of healthy and mastitic cows in Kayseri/Turkey. Milk samples from 300 cows were found to be negative/positive for mastitis with the California Mastitis Test. Candida spp. was isolated by using the Brillance Candida Agar Base. Phenotypic tests, Matrix Assisted Laser Desorption Ionization - Time of Flight (MALDI-TOF), and VITEK-2 analyses were applied to confirm the obtained isolates. Resistance to flucytosine, fluconazole and caspofungin antifungals of the isolates were determined by Etest and VITEK-2. The genetic homologies of Candida spp. isolates were determined by Repetitive Extragenic Palindromic-PCR (RepPCR). In this study 62 (from 53 healthy, 9 mastitic) yeast isolates were obtained and 37 (59.6 %) were identified as non-albicans Candida (NAC) species. Phenotypic tests revealed that out of 62 isolates, 29 (46.7 %), 4 (6.5 %), 3 (4.8 %), 1 (1.6 %) and, 24 (38.7 %) were identified as Candida lusitaniae, Candida catenulate, Candida tropicalis, Candida silvicola and other yeast species, respectively. Only one sample (1.6 %) was identified as Candida albicans by MALDI-TOF however, according to VITEK-2, the agent was not confirmed as C. albicans. According to antifungal susceptibility testing by VITEK-2, one (2.7 %) of the isolates was resistant to fluconazole, one (2.7 %) was resistant to caspofungin, and 4 (10.8 %) were resistant to flucytosine. However, using E test, 10 isolates (27 %) were resistant to flucytosine. Using Rep-PCR, eight genotypic clones were observed. Genotype F (13.8 %) and G (13.8 %; 2 subtypes) were common clones in this study. In conclusion, NAC species were detected in healthy and mastitic cow milk samples. Epidemiological studies need to be conducted to track effectively the main source and to understand the diversity and distribution of the agent. It is necessary to consider the potential risks of yeast contamination in milk for public health. It is essential to focus on adequate sanitation procedures and storage conditions of milk.
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    Escherichia coli O157 in fish: Prevalence, antimicrobial resistance, biofilm formation capacity, and molecular characterization
    (Elsevier, 2020) Onmaz, Nurhan Ertas; Yildirim, Yeliz; Karadal, Fulden; Hizlisoy, Harun; Al, Serhat; Gungor, Candan; Disli, H. Burak
    This study was performed to survey the incidence of Escherichia coli O157:H7 contamination in fish samples which were obtained from different fish farms and retail markets. For this purpose, a total of 140 fish samples were analyzed according to ISO 16654 and screened for virulence genes by mPCR. Antibiotic susceptibility tests were performed with the disc diffusion method and isolates were genotyped by using Enterobacterial repetitive intergenic consensus (ERIC) PCR. Of the 140 analyzed sample, two (1.4%), from the same farm, were found to be contaminated with E. coli O157 serogroup, one of which harbored stx1 and the other eaeA gene. E. coli O157 serogroup were resistant to only ciprofloxacin and were not capable of forming biofilm and their ERIC-PCR patterns were different. In conclusion, the existence of pathogenic E. coli O157 serogroup in fish samples might be a significant threat to public health and fish could serve as a vehicle for transmission of these bacteria to consumers in Turkey.
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    Knowledge and attitudes in food safety and the occurrence of indicator bacteria on hands of food handlers at the point of pastrami sale
    (Ankara Univ Press, 2020) Yildirim, Yeliz; Onmaz, Nurhan Ertas; Gonulalan, Zafer; Hizlisoy, Harun; Al, Serhat; Karadal, Fulden; Kum, Erhan
    The aim this study was to evaluate food safety knowledge and attitudes of food handlers and to determine the presence of indicator bacteria on the hands of food handlers in the pastrami retail points in Kayseri, Turkey. Food handlers were interviewed and the samples were taken from their hands by touching the petri dishes. Food handlers' knowledge and attitudes were evaluated by questionnaires and checklists. Conventional methods were followed for microbiological analyses. The presence of total coliforms, E. coli, members of the family Enterobacteriaceae and S. aureus on the hands of food handlers were analyzed. Results indicated that coliforms were present in 37.3% of food handlers hands and 32% exceeded the limit when compared to the literature suggesting a target value of <2.5 cfu/cm(2). E. coli, Enterobacteriaceae and S. aureus were present in 10.6%, 44.6% and 34% of handler's hands, respectively. Food safety knowledge evaluation received high scores with mean score of 69.06%. Only one handler was below the score of 50%. Despite the high scores on food safety knowledge, high numbers of hand samples were found to be contaminated with pathogens. Data obtained from this study reveal that despite their adequate food safety knowledge, food handlers on pastrami retail points were found insufficient for implementation. Therefore, it is not only sufficient to provide food safety trainings but also the sources of problems, such as lack of hygiene infrastructure, in the practice should be identified and resolved in retail points.
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    Mycotoxigenic and phylogenetic perspective to the yeasts and filamentous moulds in mould-matured Turkish cheese
    (Elsevier, 2021) Onmaz, Nurhan Ertas; Gungor, Candan; Al, Serhat; Dishan, Adalet; Hizlisoy, Harun; Yildirim, Yeliz; Tekinsen, Filiz Kasap
    This study was conducted to determine the diversity of yeasts and filamentous moulds in mould-matured cheese (MMC) consumed in Turkey. Overall, 120 samples were collected from 12 different geographical locations between March 2016 and April 2017. The morphological observation was applied in combination with matrixassisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and molecular analyses to determine yeasts and filamentous moulds in the cheeses. High-performance liquid chromatography (HPLC) technique was used to evaluate the ability of mycotoxins production of fungal isolates and the presence of mycotoxins in cheese samples. A total of 241 fungi (81 filamentous moulds and 160 yeast) were recovered, and Penicillium roqueforti and Debaryomyces hansenii were the most frequently isolated species in all cheese samples. The rep-PCR results indicated a high level of genetic diversity among fungal isolates, regardless of isolation source or geographical origin. Filamentous mould strains isolated from MMC were found to synthesize at least one mycotoxin (Aflatoxin B1, B2, G1 and G2, citrinine, cyclopiazonic acid, mycophenolic acid, ochratoxin A, penicillic acid and roquefortine C). Although mycotoxin producing ability was observed from all isolates, none of the cheese samples were found positive for these mycotoxins. AFM1 was detected in 8 (6.6%) MMC samples from which 2 (1.6%) were above the legal limits (0.05 mu g/kg) set by the Turkish Food Codex (TFC) and European Commission (EC). In conclusion, Turkish MMCs were found to be contaminated with toxigenic fungi, so a potential public health risk, while low, exists. Therefore, the selection of nontoxigenic filamentous mould strains for cheese manufacturing and control of the ripening conditions is a critical need to ensure the quality and safety of Turkish MMC.
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    Occurence and antimicrobial resistance of Staphylococcus aureus and Salmonella spp. in retail fish samples in Turkey
    (PERGAMON-ELSEVIER SCIENCE LTD, 2015) Onmaz, Nurhan Ertas; Abay, Secil; Karadal, Fulden; Hizlisoy, Harun; Telli, Nihat; Al, Serhat
    The aims of this study were to investigate the presence of Staphylococcus aureus and staphylococcal enterotoxins, as well as Salmonella spp. and to determine the antimicrobial susceptibilities of the isolates from fish samples. A total of 100 fish samples were analysed consisting of 30 anchovy, 35 trout and 35 sea bream. The presence of SEs was detected using ELISA and its genes confirmed by mPCR. Also, S. aureus and Salmonella spp. were detected in 9 (9%) and 5 (5%) samples, respectively. None of the S. aureus isolates had SEs and SEs genes. The resistance rates of the S. aureus isolates to erythromycin, tetracycline, and penicillin G were found to be 33% while Salmonella spp. isolates were resistant to trimethoprim-sulfamethoxazole, gentamicin and neomycine in 20%, 20% and 80%, respectively of the samples. It is of utmost important for public health that retail fish markets need to use hygienic practices in handling and processing operations. (C) 2014 Elsevier Ltd. All rights reserved.
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    Toxigenic Staphylococcus aureus in some animal- originated food products marketed in Turkey: presence and Public Health concerns
    (Ist Zooprofilattico Sperimentale Abruzzo & Molise G Caporale-Izs A&M, 2024) Karadal, Fulden; Onmaz, Nurhan Ertas; Hizlisoy, Harun; Yildirim, Yeliz; Al, Serhat; Gonulalan, Zafer; Bagci, Cemalettin
    This study aimed to detect the presence of Staphylococcus aureus in some animal source food (ASF) including emulsified meat products (sausage and salami), dry fermented meat product (soudjouk), semi dry meat product (pastrami) and raw chicken meat. Sixty six (38.8%) of 170 samples were found to be positive for S. aureus. . It was determined that S. aureus was found in 17 (56.6%) salami, 27 (54%) raw chicken meat, 9 (30%) soudjouk, 9 (30%) pastrami, 4 (13.3%) sausage samples. Staphylococcal enterotoxins (SEs) were identified in 5 out of 66 (7.5 %) isolates food matrices including 3 (4.5%) SEA, 2 (3.03%) SEC. The sea and sec genes were detected in 3 (4.5%) of 66 isolates. The results of this study highlight the need to provide suitable control strategies concerning production, sales, and storage to prevent the spread of enterotoxigenic S. aureus isolates in ASF. The key contribution of this study is its revelation of the presence of S. aureus in animal products sold in Turkish local markets, highlighting the potential public health risks associated with animal foods.