Gülay Merve Bayrakal

Quaternary ammonium compounds (QACs) are the most significant disinfectants utilised to control the contamination of Staphylococcus aureus in food establishments. S. aureus is a significant pathogen that carries genes responsible for resistance to QACs, which pose a risk to public health and food safety. The objective of the study was to investigate the prevalence of QAC genes (qacA/B, qacC, qacG, qacH, qacJ, and smr) and benzalkonium minimal inhibitory concentration (MIC) values in S. aureus strains isolated from food products and food production facilities (n = 200). The analysis results indicated that the qacC gene was the most frequently detected, with a prevalence of 12%. The qacA/B, qacG, qacH, qacJ, and smr genes were identified at frequencies of 2%, 3%, 1%, 4.5%, and 5%, respectively. The highest MIC level was identified in the surface sample, which carried the qacG gene, at a concentration of 6.25 μg mL⁻¹. The study's results highlight the potential risks associated with disinfectant resistance in food establishments. To prevent the transfer of disinfectant resistance genes, which have become a global risk, it is imperative that the rules of disinfectant usage are observed rigorously and that scientific research in this field is diversified.

This study investigated the toxigenic genes and antimicrobial resistance profiles of Staphylococcus aureus strains isolated from 260 raw milk samples collected from dairy farms in Türkiye. The results indicated that 60.7% of staphylococcal enterotoxin genes (sea, seb, sed, seg, sei, sej, sek, seq, sem, seo, and seu) and 21.4% of the tst and eta genes were positive, with most enterotoxin-positive samples carrying more than one gene. The sec, see, seh, sel, sen, sep, and etb genes were not identified in any samples. The prevalence of antibiotic resistance genes (mecA, blaR, blaI, blaZ, vanA, ermT, tetK, aac/aph, ant, dfrA, tcaR, IS256, and IS257) was high at 89.2%, with bla being the most frequently detected gene (75%). The mecA gene was present in 14.2% of samples, while tcaR was detected in 78.5%. Nevertheless, the mecC was not identified. Disinfectant resistance genes (qacA/B, qacC, qacJ, smr) were detected in 21.4% of the samples. The results of the disk diffusion test showed that 64.2% of strains were resistant to penicillin G and ampicillin, with additional resistance found for cefoxitin, teicoplanin, levofloxacin, norfloxacin, and other antibiotics. These findings highlight a significant public health and food safety risk associated with raw milk due to the presence of S. aureus strains with toxigenic genes and high antimicrobial resistance.

This study investigated the toxigenic genes and antimicrobial resistance profiles Staphylococcus aureus strains isolated from 260 raw milk samples collected from dairy farms in Türkiye. Results indicated that 60.7% of staphylococcal enterotoxin genes (sea, seb, sed, seg, sei, sej, sek, seq, sem, seo, and seu) and 21.4% of the tst and eta genes were positive, with most enterotoxin-positive samples carrying more than one gene. The genes sec, see, seh, sel, sen, sep, and etb were not identified in any samples. The prevalence of antibiotic resistance genes (mecA, blaR, blaI, blaZ, vanA, ermT, tetK, aac/aph, ant, dfrA, tcaR, IS256, and IS257) was high at 89.2%, with bla being the most frequently detected gene (75%). The mecA gene was present in 14.2% of samples, while tcaR was detected in 78.5%. Nevertheless, the mecC was not identified. Disinfectant resistance genes (qacA/B, qacC, qacJ, smr) were detected in 21.4% of the samples. The results of the disc diffusion test showed that 64% of strains were resistant to penicillin G and ampicillin, with additional resistance found for cefoxitin, teicoplanin, levofloxacin, norfloxacin, and other antibiotics. These findings highlight a significant public health and food safety risk associated with raw milk due to the presence of S. aureus strains with toxigenic genes and high antimicrobial resistance.

Disinfectants in the food industry are being replaced by a new generation of agents due to their disadvantages (corrosion, irritation, toxicity, residue problems etc.). Neutral electrolyzed water (NEW) has no negative effects on human, environmental or animal health. It does not alter food quality and is considered a more reliable disinfectant. Staphylococcus aureus causes serious health problems, especially food poisoning and intoxications. Quaternary ammonium (QA) disinfectant is commonly used for disinfection in the global food industry. We have investigated the efficacy of NEW at killing quaternary ammonium-resistant and non-resistant S. aureus strains in vitro, testing different concentrations (20 %, 50 %, 100 %) and treatment times (5, 30 and 120 min). The greatest reductions for both S. aureus strains were seen at 100 % concentrations, while no reduction was observed in the tap water used as control. Reductions of more than 6 log CFU/ml were achieved for both strains of S. aureus at 50 % and 100 % concentration. After 5 min of treatment, 6 log reductions were achieved for non-resistant S. aureus strains at 100 % concentration. QA-resistant strains declined to undetectable levels after 30 min. The results indicate that NEW may be effective in inactivating S. aureus strains in the food industry.

Probiyotik yoğurtların sağlık açısından birçok faydalı etkisi bulunmakta, ancak probiyotik etki göstermeleri için içerdikleri probiyotik mikroorganizma miktarının düzeyi önem taşımaktadır. Çevre koşullarından kolaylıkla etkilenen probiyotik bakterilerin canlılığı, probiyotik yoğurtların depolama, transport ve muhafazası gibi işlemler sırasında azalmaktadır. Bu çalışma kapsamında, 2 adet farklı ticari probiyotik yoğurt (PYA ve PYB) ile liyofilize probiyotik kültürden laboratuvar ortamında üretilen yoğurtlardaki (PYC) raf ömrü boyunca probiyotik kültürlerin canlılığı ve yoğurtlardaki fiziko-kimyasal değişimler incelenmiştir. Deneme deseni 3 gruptan tasarlanmış olup her deneme grubu 7 adet örnekten oluşturularak her örnek analize alınmıştır. Laktobasillerin ve Bifidobakterilerin tespiti için sırasıyla MRS-galaktoz ve MRS-sistein besiyerleri kullanılmıştır. Elde edilen bulgular doğrultusunda; her örnek grubundaki probiyotik bakteri sayısında muhafaza süresi boyunca istatistiksel olarak anlamlı bir düşüş saptanmıştır. Ayrıca, soğuk koşullarda muhafaza edilen yoğurtlardaki probiyotik Laktobasillerin ve Bifidobakterilerin canlılığında 22. güne kadar düşme, 28. günde ise önemli düzeyde azalma tespit edilmiştir. Yoğurtlardaki pH seviyelerinin de probiyotik bakteri sayısına benzer şekilde, muhafaza süresince azalma gösterdiği, 28. günde en düşük pH değerine ulaşıldığı ortaya konulmuştur. Kuru madde ve su aktivitesi değerlerinin her 3 grupta benzer şekilde olduğu, muhafaza süresi uzadıkça kuru madde miktarının arttığı, su aktivitesi değerinin ise azaldığı saptanmıştır. pH, kuru madde ve su aktivitesi değerlerinde meydana gelen değişimlerin probiyotik Laktobasillerin ve Bifidobakterilerin canlılığını etkiledikleri belirlenmiştir. Sonuç olarak, probiyotik yoğurtlarda, fiziko-kimyasal değişimler ve bakteri canlılıkları göz önünde bulundurularak, söz konusu probiyotik bakterilerden beklenen faydalı etkilerin görülmesi için soğukta muhafaza edilse dahi, 22nci gün sonrası probiyotik yoğurtların tüketimine dikkat edilmesi önerilmektedir.

Recently, there has been a growing interest in alternative protein sources. This study aimed to determine the textural and sensory properties of vegan burger patties produced with plant-based (soy and pea) protein sources instead of meat protein. For this purpose, 14 different vegan burger patties produced with soy and pea-based protein alternatives were obtained from different brands in the İstanbul market. Burger patties were analysed in terms of moisture content, cooking properties, instrumental colour, texture profile, and sensory properties. According to the results, pea-based burger patties have a higher moisture content and cooking loss and a lower cooking yield than soy-based patties. The L* and a* values of the pea-based patties tended to be higher than those of the soy-based patties, while the b* values were generally higher. In addition, the texture profile analysis of soy and pea-based burger patties shows differences in texture attributes that may affect consumer preference and overall eating experience. In the sensory evaluation, a significant difference between soy and pea-based burger patties was observed only for juiciness and spicy taste characteristics. The research findings shed light on alternative proteins' textural and sensorial properties and their role in the food industry, particularly in developing vegan burger patties. These differences in sensory attributes and colour and texture analysis between soy and pea-based burger patties highlight the importance of ingredient selection and formulation in developing plant-based protein products.

Inadequate cleaning and disinfection processes in the food industry are major causes of foodborne infections. Therefore, an effective cleaning process is essential for food production areas. Traditional disinfectants in the food industry have side effects like corrosion, irritation, toxicity, and residue problems. Therefore, electrolyzed water has become increasingly popular as an effective disinfectant in the food industry. Neutral electrolyzed water (NEW) contains hypochlorous acid and hypochlorite to inactivate pathogens effectively and has been proven to be stable. Listeria monocytogenes, a common foodborne pathogen, can be found throughout the food production chain at different points and conditions. This study examined the antimicrobial effect of NEW on L. monocytogenes at different concentrations, exposure times, and in vitro conditions. To assess the effectiveness of NEW, 0.1 %, 5 %, 10 %, 50 %, and 90 % concentrations were prepared, and the inactivation treatment was carried out for 30, 60, 90, and 120 min at room temperature. The results showed that at concentrations of 10 %, 50 %, and 90 %, the disinfectant significantly reduced the number of L. monocytogenes to undetectable levels within 30 minutes. However, about 1 log10 reduction was achieved at 0.1 % concentration in all applied times. This study reveals that NEW is highly effective for inactivating L. monocytogenes and should be used more in the food industry. In conclusion that NEW is a safe, environmentally friendly, and not harmful to food quality alternative to traditional disinfectants in the food industry, and recommended its increased use.

Gıdalar üretim transport ve satış aşamalarında en doğru prosedürler uygulanarak üretilse bile, satın alınan gıdalar, tüketicinin evine girdikten birçok farklı değişkene bağlı olarak insan sağlığı açısından çok önenmli risk faktörleri haline dönüşebililir. Bu çalışmanın amacı, Marmara bölgesi kapsamında, Edirne, Tekirdağ, Kırlareli, İstanbul, Kocaeli, Adapazarı, Yalova, Bursa, Bilecik, Balıkesir, Çanakkale illeri için, hayvansal kökenli gıda ürünleri (süt ve ürünleri, et ve ürünleri, su ürünleri, kanatlı et ve ürünleri olmak üzere) hanehalkı tüketim profillerini belirlemek ve bu ürünlerinin mikrobiyolojik açıdan durumunu değerlendirmektir. Veriler normal dağılımlı olmadığı için parametrik olmayan yöntemlerden Kruskal-Wallis testi uygulanmıştır. Analiz sonucunda, mikrobiyolojik parametreler açısından, et ve et ürünleri ile süt ve süt ürünleri için anlamlı farklılık belirlenmiştir (p0.05). Farkın kaynağına bakıldığında, hem et ve et ürünleri için hem de süt ve süt ürünleri için E. Coli ve Koliform Grubu anlamlı şekilde yüksek olarak elde edilmiştir.

Nowadays, it is important for the food industry and public health that food reaches the consumer from production to consumption without spoiling. Smart packaging technologies are one of the new technologies informing the manufacturer and customer. In order to prevent spoiled food from being consumed, it is necessary to identify the deterioration as quickly as possible. The aim of the study is to determine the applicability of smart packaging technology and usability of Digital Droplet PCR for quick and accurate spoilage detection by evaluating the quantity of genes involved in biogenic amines synthesis that occurs during spoilage. Consumption of spoiled products until products of spoilage biogenic amines, accumulated and are later on detected, may cause a threat to public health. In this study, chicken meats were analyzed on specific days in terms of microbiological, physicochemical, and molecular aspects. The 9th day was determined to be the start of the degradation when the quantity of microorganisms exceeded 10⁸ cfu/g, based on the microbiological data obtained from chicken meats. On the same day according to the ddPCR data, the gene duplication number was found to be over 50–60. Within the light of this information, the upper limit for the detection of degradation of histamine and putrescine-producing gene copy number is interpreted as 50. When the results of the microbiological analyses and ddPCR data were compared, it was shown that ddPCR method when used in combination with the smart labels, can be applicable for quick deterioration detection in smart packaging systems.