Browsing by Author "Karagözlü N."
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Item Survival characteristics of E. coli O157:H7, S. typhimurium and S. aureus during kefir fermentation(Institute of Agricultural and Food Information, 2007) Karagözlü N.; Karagözlü C.; Ergönül B.In this research, the growth and survival of E. coli O157:H7, Salmonella typhimurium and Staphylococcus aureus were investigated during kefir fermentation. Two different levels of inoculation of the strains were conducted; the levels of 102 CFU/ml (EC-1, SA-1 and S-1) and 103 CFU/ml (EC-2, SA-2 and S-2). At 0, 2, 6, 12, and 24 hours of kefir fermentation at 23 ± 1°C, samples were taken and the counts of E. coli O157:H7, S. typhimurium, and S. aureus were determined. EC-1 grew from 2.29 ± 0.02 log CFU/ml to 4.13 ± 0.18 log CFU/ml whereas EC-2 grew from 3.22 ± 0.04 log CFU/ml to 6.78 ± 0.99 log CFU/ml. Both S-1 and S-2 viable populations grew during the fermentation period, where sample S-1 grew from 2.37 ± 0.20 log CFU/ml to 4.64 ± 0.67 log CFU/ml and sample S-2 grew from 3.52 ± 0.07 log CFU/ml to 5.60 ± 0.10 log CFU/ml. SA-2 strains grew from 3.06 log CFU/ml to 3.64 log CFU/ml, SA-1 strains grew from 2.28 log CFU/ml to 2.66 log CFU/ml. According to the findings, E. coli O157:H7, S. typhimurium, and S. aureus can survive in kefir during fermentation.Item Microbiological attributes of Turkish butters sold under market conditions(2008) Karagözlü N.; Ergönül B.In this study, microbiological quality of 45 butter samples sold under market conditions at Manisa (Turkey) was investigated. Total coliform, total fecal coliform, Escherichia coli and yeast and mould counts were found between < 1.0 - > 3.15 log10 cfu.g-1, < 1.0 - > 3.15 log10 cfu.g-1, < 1.0 - > 3.15 log10 cfu.g-1 and < 1.0 - > 6.62 log10 cfu.g-1 respectively. Only in one sample Salmonella was detected. Staphylococcus aureus was not detected in any of the samples. To that extent butters sold under market conditions in Manisa have high coliform, yeast and mould contamination. © 2008 Birkhäuser Verlag, Basel.Item Determination of antimicrobial effect of mint and basil essential oils on survival of E. coli O157:H7 and S. typhimurium in fresh-cut lettuce and purslane(2011) Karagözlü N.; Ergönül B.; Özcan D.In this research, mint and basil essential oils at concentrations of 0.01 ml/L, 0.032 ml/L or 0.08 ml/L were used for disinfection treatments of fresh-cut lettuce and purslane samples inoculated with Salmonella typhimurium or Escherichia coli 0157:H7. Disinfection treatment time was applied as 10 min (short) or 15 min (long). Disinfected samples were packaged aerobically and stored at refrigerator +4 °C for 7 days. It was observed that mint and basil essential oils showed antimicrobial effect on the survival of E. coli O157:H7 and S. typhimurium inoculated into lettuce and purslane samples during refrigerated storage. Mint essential oil showed higher antimicrobial effect on pathogens when compared to basil essential oil. Mint and basil essential oils at concentration of 0.08 ml/L were the most effective antimicrobial treatment against pathogens in two different vegetable. S. typhimurium was more resistant against basil oil in lettuce samples when compared to its resistance against basil oil in purslane samples, whereas E. coli O157:H7 was more resistant to mint oil in purslane samples when compared to its resistance against mint oil in lettuce samples. © 2011 Elsevier Ltd.Item Antioxidant and antimicrobial activities of essential oils obtained from Oregano (Origanum vulgare ssp. hirtum) by using different extraction methods(2011) Karakaya S.; El S.N.; Karagözlü N.; Şahin S.In this study, antioxidant and antimicrobial activities of essential oils obtained from oregano (Origanum vulgare ssp. hirtum) were determined by using solvent-free microwave extraction (SFME), supercritical fluid extraction, and conventional hydrodistillation (CH) methods. The inhibitory effects on the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical of essential oils obtained from oregano by using SFME and CH were similar. However, essential oil extracted by CH showed greater (2.69μmol/μL of oil) Trolox equivalent antioxidant capacity (TEAC) than oregano oils obtained by SFME (P<.05). The difference between percentage inhibition and TEAC values most probably is due to the fact that undiluted and diluted samples are used in the percentage inhibition assay and the TEAC assay, respectively. TEAC values of oregano essential oils obtained by SFME at different microwave power levels were found to be similar and ranged from 0.72 to 0.84μmol/μL of oil. Essential oils obtained by CH and SFME at different microwave powers inhibited the survival of Listeria monocytogenes, Salmonella typhimurium, and Escherichia coli O157:H7, whereas survival of Staphylococcus aureus was not influenced. In addition, oregano oil obtained by SFME at 40% power level did not show any inhibitory effect on E. coli O157:H7. © Copyright 2011, Mary Ann Liebert, Inc.Item Determination of consumers' food safety knowledge and awareness: The case of Ankara, Etimesgut; [Tüketicilerin gida güvenliǧi bilgi ve bilinçlerinin belirlenmesi: Ankara, Etimesgut örneǧi](Ege Universitesi, 2022) Yüksel Ç.Y.; Karagözlü N.Objective: The objective of this study was to determine the relationship between the consumers habits of knowledge and awareness levels of food safety, consciousness in food preparation and consumption stages of the consumers living in Ankara, Etimesgut. Material and Methods: The material of the study consisted of the data obtained from the survey conducted with 517 adult volenteers with different demographic characteristics living in the Ankara, Etimesgut. The questionnaire form consisted of four parts and included questions about demographic characteristics, the level of food safety of consumers, and the level of knowledge and awareness of consumers during food preparation and consumption were asked. Results: As a result of the questions asked to determine the consumer's food preparation and consumption information and consciousness level, it was found that 7,9% of the consumers were low, 77,4% of them were middle, and 14,7% of them were highly conscious. The relationship between the questions in this group and the demographic characteristics were examined and it was concluded that the level of consciousness was statistically significant relation with gender (p <0.05) and income level (p <0.01). Conclusion: The most important resuls of the study were the answers given by the consumers who were concious about food safety but the practices in the kitchenwere wrong. These results show that the concept of food safety is fragmented in terms of knowledge and application and it is believed that if all of these parts is understood correctly, food security can be ensured. © 2022 Journal of Agriculture Faculty of Ege University. All right reserved.Item Consumers' buying habits: The case of Ankara, Etimesgut; [Tüketicilerin satın alma alışkanlıkları: Ankara, Etimesgut örneği∗](Ege Universitesi, 2023) Yanğiç Yüksel Ç.; Karagözlü N.Objective: The objective of this study was to determine the relationship between the purchasing habits of the consumers living in Etimesgut district of Ankara province with different demographic characteristics such as age, gender, income level, education level and their purchasing habits. Material and Methods: The data obtained from the survey study conducted with 517 adult individuals with different demographic characteristics were used; demographic characteristics, food buying habits and places where consumers buy foodstuffs were examined. The obtained data were evaluated by applying SPSS program and chi-square (χ2) test. Results: The relationships between the education status of the consumers and whether the packaging is damaged during shopping and the gender and the label information of the product and whether it contains allergens were found to be significant. It has been determined that consumers prefer neighborhood markets when buying products such as fruits and vegetables, and that they consider the "street vendor" as having the lowest reliability. Conclusion: During shopping, especially attention should be paid to the expiration date, whether the packaging material is damaged; constitute the most important parameters of purchasing habits. The fact that consumers prefer their own products and supermarkets as the point of access to food reveals the importance of the correct and adequate functioning of the food control mechanism through the state. © 2023 Ege Universitesi. All rights reserved.Item Utilization of pomegranate and black grape seed by-products in yogurt production: Effects on phenolic compounds and antioxidant activity(John Wiley and Sons Inc, 2024) Çalişkanlar S.; Saygili D.; Karagözlü N.; Karagözlü C.The present study investigated the potential utilization of pomegranate and black grape seed by-products of the food industry in yogurt production. Specifically, we examined the effect of polyphenols on antioxidants in yogurts produced using two different starter cultures: classical yogurt culture (Lactobacillus delbrueckii subsp. bulgaricus + Streptococcus thermophilus) and yogurt culture supplemented with L. casei. Various parameters, including pH, acidity, viscosity, fat content, protein content, dry matter content, color, microbiological properties, and sensory attributes, were analyzed in the yogurt products. The present findings indicate that incorporating pomegranate and grape seed powder and using different starter cultures significantly affected the yogurt's phenolic content and antioxidant activity. Furthermore, we observed decreased phenolic content and antioxidant activity during the 21-day storage period. Interestingly, yogurts produced with pomegranate seed powder and L. casei culture exhibited higher antioxidant activity than the other samples. Importantly, none of the yogurts containing pomegranate and grape seed powders had microbial counts below 107 cfu/g for L. delbrueckii subsp. bulgaricus, S. thermophilus, and L. casei, indicating no adverse effects on probiotic properties. Sensory evaluation revealed that the yogurt product prepared with grape seed powder and a combination of yogurt culture (L. delbrueckii subsp. bulgaricus + Streptococcus thermophilus) and L. casei was particularly well-received. In conclusion, the functional properties of grape seed powder and pomegranate seed powder make them suitable natural ingredients for enhancing the antioxidant activity of yogurt. The study highlights the potential of utilizing these by-products to develop yogurt products with added health benefits. © 2023 The Authors. Food Science & Nutrition published by Wiley Periodicals LLC.Item Green synthesis, characterisation, and antibacterial activity of silver nanoparticles obtained from Salvia officinalis extract(Czech Academy of Agricultural Sciences, 2024) Özeşer T.; Karagözlü N.The present study investigated the properties and antimicrobial activity of silver nanoparticles synthesised through a green method using Salvia officinalis. Extracts were obtained from sage at two different temperatures, and these extracts were then used to synthesise silver nanoparticles through a reaction with AgNO3. The characteristics of resulting silver nanoparticles and their antimicrobial effects on foodborne pathogenic bacteria were examined. During the synthesis, the colour of the silver nanoparticle solution changed from yellow to dark brown, and a significant absorbance peak was observed at 360 nm. The sizes of the synthesised silver nanoparticles were found to be 53.77 and 57.08 nm for the two different extraction temperatures, respectively. The nanoparticles exhibited spherical-rod shapes with silver contents of 83.91% and 84.38% and crystal sizes of 37.15 nm and 34.81 nm, corresponding to the two temperatures. The reduction of silver ions involved functional groups like C=C or C=O. The antimicrobial activity of the synthesised silver nanoparticles was evaluated at concentrations of 10 and 25 mg·mL–1 using the paper disc method against several foodborne pathogenic bacteria. Notably, the sage extract displayed antimicrobial efficacy against Salmonella Typhi, Listeria monocytogenes, and Staphylococcus aureus. However, no significant antimicrobial effect was observed against Escherichia coli O157:H7. © The authors.