Abstract Short-wave ultraviolet (UVC) irradiation is an emerging process that has been reported as an effective method for inactivating bacteria that contaminate water. Research regarding this technology in foods has focused on treating certain liquids inoculated with particular target microorganisms. We evaluated different UVC reactor arrangements with recirculation to inactivate Saccharomyces cerevisiae in grape juice. Tested juice was inoculated with S. cerevisiae and processed at three flow rates (5.2, 17.1, or 31 mL/s) during 60 min. Selected arrangements of UVC reactors were assessed by varying the length (30 or 80 cm) of the UVC lamp (254 nm), the number of lamps (1 or 2), and the thickness of the gap in the reactor (1.0 or 0.5 cm) for the 30 cm UVC lamp. Additionally, UVC dosages of studied arrangements were evaluated through dye degradation in order to determine the effect of flow rate in the recirculating systems. In UVC reactors consisting of a single lamp, approximately 2.5 log-cycle reductions were achieved with flow rates of 17.1 or 31 mL/s, whereas at 5.2 mL/s only 2 log-cycle reductions were attained. With two UVC lamps in series, 5 log-cycle reductions were achieved after 45 min of treatment regardless the length of the lamp but only at the high flow rates tested. With the reactor of the smallest tested thickness, 6 log-cycle reductions were achieved at 17.1 mL/s or 31 mL/s. In general, reduction of juice film thickness allowed greater reductions of S. cerevisiae; furthermore, important differences were observed among the evaluated systems when comparing the effect of flow rate.

中文翻译：

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以连续再循环模式运行以灭活葡萄汁中的酿酒酵母的短波紫外线照射反应器的特性和有效性

摘要 短波紫外线 (UVC) 辐照是一种新兴工艺，已被报道为灭活污染水体的细菌的有效方法。有关食品中这项技术的研究主要集中在处理接种了特定目标微生物的某些液体上。我们评估了不同的 UVC 反应器布置，通过再循环来灭活葡萄汁中的酿酒酵母。用酿酒酵母接种受试果汁，并以三种流速（5.2、17.1 或 31 mL/s）加工 60 分钟。通过改变 UVC 灯的长度（30 或 80 厘米）（254 纳米）、灯的数量（1 或 2 个）以及反应器中间隙的厚度（1.0 或 0.5 厘米）来确定 UVC 反应器的选定布置) 用于 30 cm UVC 灯。此外，通过染料降解评估所研究装置的 UVC 剂量，以确定再循环系统中流速的影响。在由单个灯组成的 UVC 反应器中，在流速为 17.1 或 31 mL/s 时实现了大约 2.5 个对数周期减少，而在 5.2 mL/s 时仅实现了 2 个对数周期减少。使用两个串联的 UVC 灯，无论灯的长度如何，但仅在测试的高流速下，处理 45 分钟后实现了 5 个对数周期减少。使用最小测试厚度的反应器，在 17.1 mL/s 或 31 mL/s 下实现了 6 个对数循环减少。一般而言，降低果汁膜厚度可以更大程度地减少酿酒酵母；此外，当比较流速的影响时，在评估系统中观察到重要。