Food Engineering / Gıda Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/12

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End date: 2019Institution Author: search.filters.institutionAuthor.Baysal, Ayşe Handan

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  • Article
    Uv-c Uygulamasının Sıvı Yumurta Beyazının Mikrobiyolojik Kalitesi Üzerine Etkisi
    (Gıda Teknolojisi Derneği, 2010) Ünlütürk, Sevcan; Baysal, Ayşe Handan; Atılgan, Mehmet R.
    Sıvı yumurta beyazı, kabuğundan ayrılmış yarı geçirgen (opak) görünümlü yumurta ürünüdür. Sıvı yumurta beyazı, düşük sıcaklık ve kısa sürelerde pastörize edilerek dayanıklı hale getirilmektedir. Ancak yüksek protein içeriği nedeni ile ısıl işlem ürün kalitesini olumsuz yönde etkilemektedir. Bu çalışma, ısıl işleme alternatif olarak öne sürülen UV-C ışınlama yöntemiyle sıvı yumurta beyazının mikrobiyolojik kalitesinin incelenmesini kapsamaktadır. Bu amaçla; yumurta beyazı örnekleri, E. coli 0157-.H7 (ATCC 700728), L. innocua (NRRL-B 33314) ve E. coli K-12 (ATCC 25253) ile inoküle edilerek belli dozlarda UV-C ışın uygulamasına tabi tutulmuştur. Denemeler 0-100 mJ/cm2UV doz aralığı ve 1.315 mW/cm2 UV şiddetinde, laboratuvar ölçekli UV dezenfeksiyon cihazı kullanılarak gerçekleştirilmiştir. Elde edilen sonuçlara göre, E. coli 0157:H7, E. coli K-12 ve L. innocua sayılarında maksimum 3.206±0.777 log, 2.719±0.63 log ve 2.624±0.268 log kob/mL azalma saptanmıştır. Sıvı yumurta beyazı üretiminde, UV-C ışınlarının bir ön işlem olarak kullanılabileceği ve ürünün mikrobiyolojik stâbilitesini artırılabileceği sonucuna varılmıştır.
  • Article
    Citation - WoS: 5
    Modeling Growth of Alicyclobacillus Acidoterrestris Dsm 3922 Type Strain Vegetative Cells in the Apple Juice With Nisin and Lysozyme
    (AIMS Press, 2017) Molva, Çelenk; Baysal, Ayşe Handan
    In the present study, the effect of storage temperature on A. acidoterrestris DSM 3922 cells (105 CFU/mL) was examined during growth in reconstituted apple juice (pH 3.8, degrees Brix 11.3) containing nisin (0-100 IU/mL) and lysozyme (0-100 mg/L). The growth curves were obtained at three temperatures of 27, 35 and 43 degrees C using absorbance data (OD600nm). Based on the results, the minimal inhibitory concentrations (MICs) of nisin were found as 10 IU/mL at all tested temperatures. On the other hand, increasing the temperature decreased the amount of lysozyme for growth inhibition. The MICs of lysozyme were found as 10, 2.5 and 1.25 mg/L at 27, 35 and 43 degrees C, respectively. At selected non-inhibitory doses, nisin (1.25-5 IU/mL) and lysozyme (0.3-2.5 mg/L) prolonged the lag time compared to the controls at the corresponding temperatures. In addition, there was a strong linear relationship between the lag time and lysozyme concentrations at 27 and 35 degrees C (R-2 > 0.98). The results of this study demonstrated that both nisin and lysozyme could be used to inhibit the growth of A. acidoterrestris cells in the apple juice. The results also indicated that the growth parameters were variable depending on the storage temperature and the type of the antimicrobial agent used in the apple juice.
  • Article
    Citation - WoS: 13
    Citation - Scopus: 17
    Characterization of Antimicrobial Activities of Olive Phenolics on Yeasts Using Conventional Methods and Mid-Infrared Spectroscopy
    (Springer, 2019) Canal, Canan; Özen, Banu; Baysal, Ayşe Handan
    Olive fruit is very rich in terms of phenolic compounds. Antimicrobial activities of various phenolic compounds against bacteria and fungi are well established; however, their effects on yeasts have not been examined. Aim of this study was to investigate the antimicrobial effects induced by olive phenolic compounds, including tyrosol, hydroxytyrosol, oleuropein, luteolin and apigenin against two yeast species, Aureobasidium pullulans and Saccharomyces cerevisiae. For this purpose, yeasts were treated with various concentrations (12.5-1000ppm) of phenolic compounds and reduction in yeast population was followed with optical density measurements with microplate reader, yeast colony forming units and mid-infrared spectroscopy. All phenolic compounds were effective on both yeasts, especially 200ppm and higher concentrations have significant antimicrobial activity; however, effects of lower levels depend on the type of phenolic compound. According to mid-infrared spectral data, significant changes were observed in 1200-900cm(-1) range corresponding to carbohydrates of yeast structure as a result of exposure to all phenolic compounds except tyrosol. Spectra of tyrosol and luteolin treated yeasts also showed changes in 1750-1500cm(-1) related to amide section and 3600-3000cm(-1) fatty acid region. Since phenolic compounds from olives were effective against yeasts, they could be used in food applications where yeast growth showed problem. In addition, FTIR spectroscopy could be successfully used to monitor and characterize antimicrobial activity of phenolic compounds on yeasts as complementary to conventional microbiological methods.
  • Book Part
    Citation - Scopus: 21
    Short-Wave Ultraviolet Light Inactivation of Pathogens in Fruit Juices
    (Elsevier, 2018) Baysal, Ayşe Handan
    Fruit juice processing techniques are continuously developing to conform to modern consumer demands for safe, nutritious, tasty, natural, and fresh-like products. Short-wave ultraviolet (UV-C) light has been proven to be a suitable alternative processing method because of its positive consumer image and low processing cost. The use of UV-C light at 253.7. nm for food processing is safe and has been approved as an alternative treatment to reduce pathogens and other microorganisms in the production, processing, and handling of foods. The bactericidal mechanism of UV-C is based on the absorption of UV-C light by microbial DNA or RNA structures and the formation of pyrimidine dimers, preventing replication, making pathogens inactive and unable to cause infection. Fruit juices have a range of optical and physical properties and diverse chemical compositions that influence UV-C efficacy. Thus, this chapter describes the effect of UV-C light applications on the inactivation of pathogens in fruit juice and critical factors to ensure efficient treatment. © 2018 Elsevier Inc. All rights reserved.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Comparison 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 Handan
    The 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.
  • Conference Object
    Microbiological Risk Assessment and Preventive Actions in Bakery and Beverage Industries in Estonia, Slovenia and Turkey
    (Technical Research Center of Finland, 2008) Baş, Duygu; Baysal, Ayşe Handan; Ehavald, Helen; Eroğlu, Erdal; Filip, Sebastjan; Köksal, Fatma; Marin, Monika; Perne, Gregor; Türetgen, İrfan; Weiss, Martina; Akdoğan, Günay; Veskus, Tiina
    Risks from microbiological hazards are of immediate and serious concern to human health. Microbiological Risk Analysis (MRA) is a process consisting of three components: risk assessment (RA), risk management (RM), and risk communication (RC), which have the overall objective to ensure public health protection. The MRA process should include quantitative information to the greatest extent possible in the estimation of risk. A MRA should be conducted using a structured approach. Since MRA is a developing science, implementation of the guidelines may require a period of time and may also require specialized training in the countries that consider it necessary. This may be particularly the case for developing countries. This document deals with risk assessment, which is a key element in assuring that sound science is used to establish standards, guidelines and other recommendations for bakery and beverage safety to enhance consumer protection and facilitate international trade. This document will be of primary interest to governmental and research organizations, companies, and other interested parties who need to prepare a MRA will find it valuable.
  • Conference Object
    Citation - Scopus: 1
    Short Wave Ultraviolet Light (uvc) Disinfection of Surface - Inhibition of Alicyclobacillus Acidoterrestris Spores on Agar Medium
    (Technical Research Center of Finland, 2008) Baysal, Ayşe Handan; Ünlütürk, Sevcan
    Alicyclobacillus species are thermoacidophilic spoilage spore-formers found in soil. The spores can survive the normal hot fill processes that are carried out on commercial fruit juices. It seems likely that fruit in contact with soil are susceptible to contamination by Alicyclobacillus. Beverage ingredients e.g. liquid sugar are also a potential contamination sources. Alicyclobacillus has also been isolated from citrus processing lines.
  • Conference Object
    Bacterial Foodborne Pathogens of Concern
    (VTT Technical Research Center of Finland, 2007) Roasto, Mati; Reinmüller, Berit; Vokk, Raivo; Baysal, Ayşe Handan; Polanc, Julijana; Veskus, Tiina; Juhkam, Kadrin; Terentjeva, Margarita; Mackiw, Elzbieta
    A high level of protection of public health is one of the fundamental objectives of food law as laid down in regulations (EC) No 178/2002 and 852/2004. Throughout the European Union (EU) consumers are requiring the food industry to provide them with an increasing range of safe, nutritious and healthy foods of high sensory quality and increased shelf life. To meet the demand for healthier food of high sensory quality, the use of additives and preservatives is being reduced or eliminated and minimal processing techniques introduced. To increase food safety and quality considerable amount of time, effort and money has been spent to food safety control and management (ISO 22000:2005) systems including better packaging methods and improved new pathogen detection methods.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 6
    The Effect of Sporulation Medium on Alicyclobacillus Acidoterrestris Guaiacol Production in Apple Juice
    (Academic Press Inc., 2016) Molva, Çelenk; Baysal, Ayşe Handan
    The present study evaluated the effect of sporulation medium on guaiacol formation from vanillin and vanillic acid by Alicyclobacillus acidoterrestris DSM 3922 in the reconstituted apple juice (pH 3.82, °Brix 11.3). For sporulation, potato dextrose agar and Bacillus acidoterrestris agar were used. After heat-activation, spores were turned into vegetative cells and inoculated into juice samples to a final concentration of 103 or 105 CFU/mL. Samples were incubated at 37 °C for 264 h and guaiacol concentration was determined using peroxidase enzyme colourimetric assay. Based on the results, the conversion of vanillic acid into guaiacol was faster than that of vanillin among both cell suspensions. Also, there were no significant differences among any of the samples inoculated into apple juice spiked with vanillin at the end of the incubation period (P > 0.05). In the case of vanillic acid, the guaiacol concentrations were significantly different among cells activated from spores produced on PDA and BATA (P < 0.05). The obtained results suggested that type of sporulation medium composition may affect the guaiacol concentration depending on inoculum level and type of precursor present in the apple juice.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Microbial Profile and Bacterial Characterisation of Naturally Debittered Hurma Olives Compared To Non-Debittered Erkence Variety During Ripening Period
    (John Wiley and Sons Inc., 2016) Sözbilen, Gözde Seval; Baysal, Ayşe Handan
    Naturally debittered Hurma olive is grown in a specific area in Karaburun peninsula in Turkey. It is characterised by its sweet taste and it differs from other varieties by losing its bitterness caused by phenolic compounds during its maturation period on the tree. Therefore, Hurma olive does not require any further debittering process to be served as table olive. This study was particularly interested in the comparison of the microbial profile of Hurma olive during its 8 weeks of maturation period in two subsequent harvest years and Erkence (not naturally debittered) olive. In addition, main bacterial profile of both Hurma and Erkence olives were isolated and identified. Aerobic mesophilic microorganism (AMM), lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonadaceae, Staphylococci, Micrococcaceae, yeasts and moulds (Y&Ms) were detected (counted and isolated) in the olive drupes during the maturation period. Isolated bacteria were identified as different spp. of Bacillaceae, Enterobacteriaceae, Micrococcoceae and Pseudomonadaceae.