Publication: Kombu çayının campylobacter sp. üzerine antimikrobiyal etkisinin belirlenmesi ve prediktif mikrobiyoloji yöntemleriyle modellenmesi
Abstract
Amaç: Bu çalışmanın amacı, Campylobacter sp.'nin hayatta kalımını etkileyen çevresel faktörleri prediktif mikrobiyoloji yöntemleriyle incelemek ve kombu çayının bu bakteriye karşı antimikrobiyal etkilerini değerlendirmektir. Böylece, doğal antimikrobiyallerin gıda güvenliğinde kullanım potansiyelini ortaya koymak ve Campylobacter sp.’nin hayatta kalım dinamiklerine ilişkin literatüre katkı sağlamak hedeflenmiştir. Gereç ve Yöntem: Çalışmada, Campylobacter sp.’in Microbial Responses Viewer (MRV)’den alınan farklı çevresel koşullardaki hayatta kalım verileri Weibull denklemiyle modellenmiştir. Sıcaklık, pH ve su aktivitesinin (aw) Weibull parametreleri (ilk azalış süresi ve şekil parametresi) üzerindeki etkileri Kruskal-Wallis testi, box-whisker grafikleri ve genel regresyon yaklaşımıyla incelenmiştir. Ardından, düşük pH’ye sahip kombu çaylarının fermentasyon süresince mikrobiyal özellikleri ve pH değişimi değerlendirilmiştir. Campylobacter sp. üzerindeki antimikrobiyal etkileri agar kuyu difüzyon ve broth mikrodilüsyon yöntemleriyle test edilmiştir. Bulgular: MRV'den toplanan verilere göre, Weibull denklemi ile Campylobacter jejuni’nin hayatta kalımı iyi uyum göstermiştir (R>0,85). Genel regresyon yaklaşımına göre, ilk azalış süresinin sıcaklık ile korelasyonu negatifken, pH ve aw ile korelasyonu pozitif bulunmuştur. Şekil parametresi üzerine sadece pH’nin önemli etkisi kaydedilmiştir. Dört farklı substratla (yeşil ve siyah çay, mor reyhan, zeytin yaprağı) hazırlanan asidik profildeki kombu çaylarının mikrobiyal içeriği değerlendirilmiştir. Hem agar kuyu difüzyon yöntemiyle hem de broth mikrodilüsyon yöntemiyle kombu çayı örneklerinin Campylobacter sp.'ye karşı antimikrobiyal etkiye sahip oldukları görülmüştür. Sonuç: Sıcaklık, pH ve aw’nin Campylobacter'in hayatta kalımında etkili olduğu, ancak suş farklılığı, biyofilm oluşumu, oksijen varlığı gibi diğer değişkenlerin de model başarısını etkileyebileceği gösterilmiştir. Kombu çayının antimikrobiyal etkisinin yalnızca düşük pH’den kaynaklanmadığı, çay tanenleri ve mikrobiyota tarafından üretilen metabolitlerin bu etkiye katkıda bulunabileceği düşünülmüştür. Bu sonuçlar, kombu çayının Campylobacter sp.’ye karşı potansiyel bir doğal antimikrobiyal olarak değerlendirilmesi için temel bir çerçeve sunmaktadır.
Objective: The objective of this study was to examine the environmental factors influencing the survival of Campylobacter sp. through the utilisation of predictive microbiology techniques and to assess the antimicrobial efficacy of kombucha against this bacterium. Consequently, the intention was to illustrate the potential of natural antimicrobials in food safety and to contribute to the existing literature on the survival dynamics of Campylobacter sp. Materials and Methods: In this study, the survival data of Campylobacter sp. in different environmental conditions obtained from the Microbial Responses Viewer were modelled using the Weibull equation. The effects of temperature, pH and water activity on the Weibull parameters were analysed using the Kruskal-Wallis test, box-whisker plots and general regression approach. Subsequently, the microbial properties and pH change of kombucha, which has a low pH, were evaluated during fermentation. Its antimicrobial effects on Campylobacter sp. were tested using the agar well diffusion and broth microdilution methods. Results: The data collected from MRV demonstrated that the survival of Campylobacter jejuni was well fitted with the Weibull equation (R>0.85). The general regression approach revealed a negative correlation between the first reduction time and temperature, while a positive correlation with pH and aw. Only a significant effect of pH on the shape parameter was recorded. The microbial content of kombucha with an acidic profile, prepared with four different substrates (green and black tea, purple basil, olive leaf), was evaluated. Both agar well diffusion and broth microdilution methods demonstrated that kombucha samples exhibited antimicrobial activity against Campylobacter sp. Conclusion: Temperature, pH and aw were effective in the survival of Campylobacter; however, other variables, including strain differences, biofilm formation, and the presence of oxygen, may also influence the success of the model. The antimicrobial effect of kombucha is not solely attributable to its low pH, but may also be influenced by tea tannins and metabolites produced by the microbiota. These findings provide a fundamental framework for the assessment of kombucha as a natural antimicrobial agent against Campylobacter sp.
Objective: The objective of this study was to examine the environmental factors influencing the survival of Campylobacter sp. through the utilisation of predictive microbiology techniques and to assess the antimicrobial efficacy of kombucha against this bacterium. Consequently, the intention was to illustrate the potential of natural antimicrobials in food safety and to contribute to the existing literature on the survival dynamics of Campylobacter sp. Materials and Methods: In this study, the survival data of Campylobacter sp. in different environmental conditions obtained from the Microbial Responses Viewer were modelled using the Weibull equation. The effects of temperature, pH and water activity on the Weibull parameters were analysed using the Kruskal-Wallis test, box-whisker plots and general regression approach. Subsequently, the microbial properties and pH change of kombucha, which has a low pH, were evaluated during fermentation. Its antimicrobial effects on Campylobacter sp. were tested using the agar well diffusion and broth microdilution methods. Results: The data collected from MRV demonstrated that the survival of Campylobacter jejuni was well fitted with the Weibull equation (R>0.85). The general regression approach revealed a negative correlation between the first reduction time and temperature, while a positive correlation with pH and aw. Only a significant effect of pH on the shape parameter was recorded. The microbial content of kombucha with an acidic profile, prepared with four different substrates (green and black tea, purple basil, olive leaf), was evaluated. Both agar well diffusion and broth microdilution methods demonstrated that kombucha samples exhibited antimicrobial activity against Campylobacter sp. Conclusion: Temperature, pH and aw were effective in the survival of Campylobacter; however, other variables, including strain differences, biofilm formation, and the presence of oxygen, may also influence the success of the model. The antimicrobial effect of kombucha is not solely attributable to its low pH, but may also be influenced by tea tannins and metabolites produced by the microbiota. These findings provide a fundamental framework for the assessment of kombucha as a natural antimicrobial agent against Campylobacter sp.