Browsing by Author "Tirik, Nihan"

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Analysis of some physical, chemical and microbiological aspects of honey samples produced and consumed in Turkey
(Univ Nacional Cuyo, 2016-08-17) Bakırdere, Sezgin; Yaroğlu, Tolga; Tirik, Nihan; Karaca, Abdullah; Demiröz, Mehmet; Uludağ Üniversitesi/Karacabey Meslek Yüksekokulu.; 55670588100
Analysis of honey produced in the western part of Turkey was carried out in this study. Fifty honey samples, collected from the local market in this region were analyzed for their physicochemical parameters including hydroxymethylfurfural (HMF), electrical conductivity, sucrose, free acidity, moisture and water insoluble impurities, in addition to pathogenic microorganisms present. HMF amounts determined in 47 samples were found to be between 1.9 and 98.0 mg/kg with good reproducibilities (% RSD: 3.2% or better). There were no pathogenic microorganisms in any of the investigated samples. Electrical conductivity that gives information about their mineral contents was measured, and the mean value was found to be 0.33 mS/cm (N=34). In general, most of the samples were considered to meet the requirements of Turkish Food Codex and European Commission Directives.
Determination of As, Cd, and Pb in tap water and bottled water samples by using optimized GFAAS system with Pd-Mg and Ni as matrix modifiers
(Hindawi Publishing, 2013) Bakırdere, Sezgin; Yaroǧlu, Tolga; Tirik, Nihan; Fidan, Ali Kemal; Maruldalı, Onur; Karaca, Abdullah; Demiröz, Mehmet; Uludağ Üniversitesi/Karacabey Meslek Yüksekokulu.; 55670588100
Arsenic, lead and cadmium were determined in tap and bottled water samples consumed in the west part of Turkey at trace levels. Graphite Furnace Atomic Absorption Spectrometry (GFAAS) was used in all detections. All of the system parameters for each element were optimized to increase sensitivity. Pd-Mg mixture was selected as the best matrix modifier for As while the highest signals were obtained for Pb and Cd in the case of Ni used as matrix modifier. Detection limits for As, Cd, and Pb were found to be 2.0, 0.036 and 0.25 ng/mL, respectively. 78 tap water and 17 different brands of bottled water samples were analyzed for their As, Cd and Pb contents under the optimized conditions. In all water samples, concentration of cadmium was found to be lower than detection limits. Lead concentration in the samples analyzed varied between N.D. and 12.66 +/- 0.68 ng/mL. The highest concentration of arsenic was determined as 11.54 +/- 2.79 ng/mL. Accuracy of the methods was verified by using a certified reference material namely Trace Element in Water, 1643e. Results found for As, Cd, and Pb in reference materials were in satisfactory agreement with the certified values.
Determination of trace aflatoxin levels in agricultural products and foodstuffs using ELISA system after immunoaffinity clean-up procedure
(Edizioni Minerva Medica, 2014-12) Bakırdere, Sezgin; Yaroğlu, T.; Tirik, Nihan; Karaca, Abdullah; Demiröz, Mehmet; Uludağ Üniversitesi/Karacabey Meslek Yüksekokulu.; 55670588100
Total aflatoxin level as naturally occurring mycotoxin were determined in different foodstuffs such as apricot, figs, raisins, peanut butter, bread, tahin-pekmez (sesame oil-molasses) and red paprika commonly consumed in Turkey. Immunoaffinity column was used to eliminate or minimize the interferences coming from the matrix by cleaning-up the samples prior to measurement step. Recovery experiments were performed to check the reliability of the column clean-up procedure. Accuracy of the method was also checked by using rice as test material (T04151) and the results found were in good agreement with the certified value. Concentration of aflatoxins was found to be higher than quantitation limit in most of the bread samples. The highest concentration of aflatoxin was found in raisin as 3.90 mu g kg(-1) while aflatoxin level ranged between 0.72-2.30 mu g kg(-1) in red paprika.
Determination of trace aflatoxin M1 levels in milk and milk products consumed in Turkey by using enzyme-linked immunosorbent assay
(Taylor & Francis, 2014-01-02) Bakırdere, Sezgin; Yaroǧlu, Tolga; Tirik, Nihan; Karaca, Abdullah; Demiröz, Mehmet; Uludağ Üniversitesi/Karacabey Meslek Yüksekokulu.; 55670588100
Aflatoxin M1 (AFM1) levels in milk and milk products (kasar cheese, tulum cheese, dil cheese, cream cheese, white cheese) consumed in Turkey were determined in this study by using enzyme-linked immunosorbent assay (ELISA). Extraction procedure was optimised to obtain high extraction efficiency. Recovery experiment was also performed to test the suitability of the extraction system and it was observed that % recovery values for AFM1 were higher than 92%. The method used in this study was simple and suitable for the detection of AFM1 in these matrices. Results found from the samples were compared with the requirements of Turkish Food Codex (TFC). As much as 42.16% of cheese samples analysed were contaminated while 61/77 milk samples were found to be contaminated with AFM1 in the range of 0.005-0.410 mu g/L. It was found that five white cheese, one kasar cheese and four milk samples exceeded the criteria of 0.5 g/kg for cheese and 0.05 g/L for milk set by TFC.