As a result of increasing interest in non-thermal technologies as a possible alternative or complementary to milk pasteurization processing, the objectives of this study were to determine the effects of different ultraviolet-C light doses on the viability of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium and chemical changes to camel milk components. Pasteurized and inoculated camel milk samples were ultraviolet-C treated in a continuous flow system. The viability of E. coli O157:H7 and S. Typhimurium was evaluated with both in vivo imaging system and traditional plate count agar method. Samples subjected to the 4.15, 8.30, and 12.45 mJ/cm2 of ultraviolet-C treatment resulted in 1.9, 3.3, and 3.9-log reductions in E. coli O157:H7 and 0.9, 3, and 3.9-log reductions in S. Typhimurium, respectively. The measurement of secondary lipid peroxidation products (or ThioBarbituric Acid Reactive Substance values) showed no significant (P > 0.05) differences between the raw and ultraviolet-C treated milk samples. Additionally, no changes (P > 0.05) in the protein profiles of αs1-casein, α-lactalbumin, and lactoferrin were observed between both samples. Compared to the untreated raw milk, c9t11 conjugated linoleic acid decreased (P < 0.01) while t10c12 conjugated linoleic acid increased (P < 0.01) in the ultraviolet-C treated milk. Furthermore, three new volatile compounds were identified in the ultraviolet-C treated milk compared to the control. In conclusion, milk treated with the ultraviolet-C light at a dose of 12.45 mJ/cm2 did not meet the Food and Drug Administration (FDA) requirements for the 5-log pathogen reduction. The ultraviolet-C treatment, on the other hand, had minimal effects on camel milk components.

中文翻译：

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不同UV-C光剂量对微生物减少及骆驼奶成分的影响

由于人们对非热技术作为牛奶巴氏杀菌处理的可能替代或补充的兴趣日益浓厚，本研究的目的是确定不同紫外线 C 光剂量对大肠杆菌 O157:H7 和沙门氏菌活力的影响enterica serovar Typhimurium 和骆驼奶成分的化学变化。巴氏杀菌和接种的骆驼奶样品在连续流动系统中进行紫外线 C 处理。使用体内成像系统和传统平板计数琼脂方法评估了大肠杆菌 O157:H7 和鼠伤寒沙门氏菌的生存能力。经过 4.15、8.30 和 12.45 mJ/cm2 紫外线 C 处理的样品导致大肠杆菌 O157:H7 的对数减少 1.9、3.3 和 3.9 对数，鼠伤寒沙门氏菌的对数减少了 0.9、3 和 3.9 对数， 分别。二次脂质过氧化产物（或硫代巴比妥酸反应物质值）的测量表明，未加工和经紫外线 C 处理的牛奶样品之间没有显着差异（P > 0.05）。此外，在两个样品之间观察到 αs1-酪蛋白、α-乳清蛋白和乳铁蛋白的蛋白质谱没有变化（P > 0.05）。与未经处理的原料奶相比，经过紫外线 C 处理的牛奶中，c9t11 共轭亚油酸降低（P < 0.01），而 t10c12 共轭亚油酸增加（P < 0.01）。此外，与对照相比，在经过紫外线 C 处理的牛奶中发现了三种新的挥发性化合物。总之，用 12.45 mJ/cm2 剂量的紫外线 C 光处理的牛奶不符合食品和药物管理局 (FDA) 对病原体减少 5-log 的要求。