Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 2Citation - Scopus: 2Comparison of Conventional Culture Method and Fluorescent in Situ Hybridization Technique for Detection of Listeria Spp. in Ground Beef, Turkey, and Chicken Breast Fillets in Izmir, Turkey(International Association for Food Protection, 2014) Baysal, Ayşe HandanThe occurrence of Listeria species in refrigerated fresh chicken breast fillet, turkey breast fillet, and ground beef was evaluated, comparing the conventional culture method and fluorescent in situ hybridization (FISH). FISH uses hybridization of a nucleic acid sequence target of a microorganism with a specific DNA probe labeled with a fluorochrome and imaging by a fluorescence microscope. First, Listeria was inoculated in chicken breast fillet, turkey breast fillet, or ground beef, and the applicability of the FISH method was evaluated. Second, Listeria was detected in fresh chicken breast fillet, turkey breast fillet, and ground beef by culture and FISH methods. Listeria was isolated from 27 (37.4%) of 216 samples by the standard culture method, whereas FISH detected 25 (24.7%) preenriched samples. Of these isolates, 17 (63%) were L. innocua, 6 (22%) L. welshimeri, and 4 (14.8%) L. seeligeri. Overall, the prevalences of Listeria spp. found with the conventional culture method in chicken breast fillet, turkey breast fillet, and ground beef were 9.7, 6.9, and 20.8%, whereas with the FISH technique these values were 11.1, 6.9, and 16.7%, respectively. The molecular FISH technique appears to be a cheap, sensitive, and time-efficient procedure that could be used for routine detection of Listeria spp. in meat. This study showed that retail raw meats are potentially contaminated with Listeria spp. and are, thus, vehicles for transmitting diseases caused by foodborne pathogens, underlining the need for increased precautions, such as implementation of hazard analysis and critical control points and consumer food safety education.Article Citation - WoS: 62Citation - Scopus: 73Antioxidant and Antimicrobial Activities of Thyme and Clove Essential Oils and Application in Minced Beef(John Wiley and Sons Inc., 2015) Zengin, Hatice; Baysal, Ayşe HandanIn this study, thyme and clove essential oils (EOs) were studied for their chemical composition, antioxidant, antiradical and antibacterial activity and application in ground beef. Carvacrol (75.27%) and eugenol (75.2%) were detected by gas chromatography-mass spectrometry analysis as the main components of thyme and clove EOs, respectively. Broth microdilution method showed all bacteria inhibited by the EOs, while Shewanella putrefaciens and Listeria innocua were the most resistant bacteria to thyme and clove EOs, respectively. EO treatment restricted the growth of artificially inoculated Salmonella typhimurium and native Coliforms in the ground beef. Antioxidant activity determined by ferric-reducing antioxidant power and 1,1 diphenyl-2-picrylhydrazyl methods demonstrated that clove EO had higher in vitro antioxidant activity than thyme EO. Similar results were obtained in ground beef application using 2-thiobarbituric acid value. EOs of clove (2MIC) exerted remarkable higher antioxidant activity in ground beef than EOs of thyme (4MIC), which represent valid alternative antioxidant in meat products. Practical Applications: Plant essential oils (EOs) serve as a "safe" alternative to chemical or synthetic antimicrobials and antioxidants to struggle with the foodborne pathogens or spoilage organisms, inhibiting lipid oxidation and thus extending shelf life. Antioxidant activity determined by ferric-reducing antioxidant power and 1,1 diphenyl-2-picrylhydrazyl methods showed that clove EO had higher in vitro antioxidant activity than thyme EO. Results obtained using 2-thiobarbituric acid value in ground beef application were found similar. EOs of clove (2MIC) exerted higher antioxidant activity in ground beef than EOs of thyme (4MIC). Therefore, EOs could be a valid alternative antioxidant in meat products.Article Citation - WoS: 70Citation - Scopus: 88Inactivation Kinetics of Alicyclobacillus Acidoterrestris Spores in Orange Juice by Ohmic Heating: Effects of Voltage Gradient and Temperature on Inactivation(International Association for Food Protection, 2010) Baysal, Ayşe Handan; İçier, FilizThe effectiveness of ohmic and conventional heating for reducing spores of Alicyclobacillus acidoterrestris was investigated in commercial pasteurized orange juice. The kinetic parameters (D- and z-values) were determined during ohmic and conventional heating. The effects of temperature (70. 80, and 90 °C) and heating time (0, 10, 15, 20, and 30 min) on inactivation of A. acidoterrestris spores during ohmic heating in orange juice were significant (P < 0.05). For 70°C, the voltage gradient also had an effect on inactivation kinetics. At 30 V/cm, D-values at 70, 80, and 90°C were 58.48, 12.24, and 5.97 min, respectively. D-values at corresponding temperatures for conventionally heated spores were 83.33, 15.11, and 7.84 min, respectively. Results showed significantly higher lethality for spores treated with ohmic heating than for spores treated with conventional heating. Conventional heating was ineffective for pasteurizing orange juice, whereas the maximum ohmic heating treatment applied at 30 V/cm was sufficient to inactivate 5 log units of A. acidoterrestris spores. Copyright ©, International Association for Food Protection.