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Journals / Niğde Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi / 2026 / Cilt: 18

Effects of brewing parameters on the microbiological safety and physicochemical properties of cold brew coffee

Demleme parametrelerinin soğuk demleme kahvenin mikrobiyolojik güvenliği ve fizikokimyasal özellikleri üzerindeki etkileri

Gamze Üçok(Necmettin Erbakan Üniversitesi)0000-0002-7692-9700
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Publication Date
2026-10-06
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

Brewing time had a greater influence on microbial survival and several quality attributes.

📌 3 Key Takeaways

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Objective & Hypothesis:Cold brew coffee has gained increasing popularity because of its distinctive sensory characteristics; however, the absence of thermal processing raises concerns regarding microbiological safety.
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Key Findings & Data:This study investigated the effects of brewing temperature (4 and 22 °C) and brewing time (6, 12, and 24 h) on the survival of Escherichia coli, Staphylococcus aureus, and Salmonella Typhimurium, as well as the physicochemical properties of cold brew coffee.
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Conclusion & Impact:Brewing time had a greater influence on microbial survival and several quality attributes.
🔬Design:Araştırma Makalesi
📍Scope:Comprehensive Sample
⚙️Variables:Soğuk demleme kahve · Gıda güvenliği · Patojen canlılığı

Abstract

Cold brew coffee has gained increasing popularity because of its distinctive sensory characteristics; however, the absence of thermal processing raises concerns regarding microbiological safety. This study investigated the effects of brewing temperature (4 and 22 °C) and brewing time (6, 12, and 24 h) on the survival of Escherichia coli, Staphylococcus aureus, and Salmonella Typhimurium, as well as the physicochemical properties of cold brew coffee. Brewing temperature did not significantly affect pathogen survival, whereas longer brewing significantly reduced the viable counts of S. aureus and S. Typhimurium (p < 0.05). E. coli was detected only after brewing at 4 °C for 6 h (3.26 log CFU/mL), whereas all other treatments were below the detection limit. During refrigerated storage, S. aureus became undetectable after 7 days, whereas S. Typhimurium persisted throughout storage. The pH remained stable (5.18–5.32) during refrigerated storage, whereas dry matter content and color parameters were significantly affected by the interaction between brewing temperature and brewing time (p < 0.05). The highest total phenolic content (144.49 mg GAE/100 mL) and antioxidant activity (IC50 = 1.178 mg dry extract/mL) were obtained after brewing at 22 °C for 6 h. Brewing time had a greater influence on microbial survival and several quality attributes.

Özet

Soğuk demleme kahve, kendine özgü duyusal özellikleri nedeniyle giderek daha fazla popülerlik kazanmakta; ancak ısıl işlem uygulanmaması mikrobiyolojik güvenlik açısından endişe oluşturmaktadır. Bu çalışmada, demleme sıcaklığının (4 ve 22 °C) ve demleme süresinin (6, 12 ve 24 saat), Escherichia coli, Staphylococcus aureus ve Salmonella Typhimurium'un canlılığı ile soğuk demleme kahvenin fizikokimyasal özellikleri üzerindeki etkileri araştırılmıştır. Demleme sıcaklığı patojen canlılığı üzerinde anlamlı bir etki göstermezken, demleme süresinin uzaması S. aureus ve S. Typhimurium canlı sayılarında anlamlı azalmaya neden olmuştur (p < 0,05). E. coli yalnızca 4 °C'de 6 saatlik demleme sonrasında (3,26 log CFU/mL) tespit edilmiş, diğer tüm uygulamalarda ise tespit sınırının altında kalmıştır. Soğukta depolama süresince S. aureus 7. günden sonra tespit edilemezken, S. Typhimurium depolama boyunca varlığını sürdürmüştür. Depolama boyunca pH değerleri (5,18–5,32) sabit kalırken, kuru madde miktarı ve renk parametreleri demleme sıcaklığı ile süresinin etkileşiminden anlamlı düzeyde etkilenmiştir (p < 0,05). En yüksek toplam fenolik madde miktarı (144,49 mg GAE/100 mL) ve antioksidan aktivite (IC50 = 1,178 mg kuru ekstrakt/mL) 22 °C'de 6 saatlik demleme sonunda elde edilmiştir. Demleme süresi, mikrobiyal canlılık ve kalite özellikleri üzerinde daha belirleyici olmuştur.

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Cite This Article

Üçok, G. (2026). Effects of brewing parameters on the microbiological safety and physicochemical properties of cold brew coffee. Niğde Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi, Cilt: 18. https://doi.org/10.28948/ngumuh.2003569

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