Consumer growing demands for high-quality and safe food and beverages have stimulated the interest in alternative preservation technologies. Short-wavelength ultraviolet light (UV-C, 254 nm) has proven to be useful for the decontamination of a great variety of clear juices while improving their quality compared to traditional thermal treatments. Suspended solids and coloured compounds in turbid juices, diminish light transmission. The use of UV-C under a hurdle approach, may be a promising strategy for their treatment. The purpose of this study was to analyse Escherichia coli ATCC 25922, Saccharomyces cerevisiae KE 162 and Lactobacillus plantarum ATCC 8014 inactivation in clear pear juice (PJ), turbid orange-tangerine (OT) and orange-banana-mango-kiwi-strawberry (OBMKS) juices processed by single UV-C (390 mJ/cm², 20 °C) and UV-C assisted by mild heat (UV-C/H, 50 °C) at pilot-scale in a coiled tubing unit and stored under refrigeration (5 °C). Inactivation studies were also conducted in peptone water (PW) and model solution (MS). The adequacy of the Coroller, Weibull and Biphasic Plus Shoulder models was studied. UV-C was highly effective in PW, MS and PJ, achieving up to 5.5-6.3-4.7, 4.8-5.1-4.6 and 4.4-5.5 log reductions for L. plantarum, E. coli,and S. cerevisiae, respectively. Whereas, a moderate inactivation by single UV-C was recorded in the turbid blends, reducing up to 2.4-3.8-1.6 and 3.6-3.7-1.3 log-cycles in OT and OBMKS, respectively. When the UV-C/H treatment was applied, high bacterial inactivation was observed achieving 5.2-5.6, 6.3-6.6 and 5.5-6.7 log reductions in OT, OBMKS and PJ, respectively, while 4.6-4.9 log reductions were determined for the yeast in OBMKS and OT, respectively. Thus, additive inactivation effects between UV-C and H were observed. All the models tested gave useful information regarding the existence of microbial subpopulations with varying resistances. However, the cumulative Weibull distribution function was the most versatile one, fitting inactivation curves with different shapes. Additionally, the frequency distributions of resistances showed that UV-C/H not only increased the UV-C microbicidal effect but changed the distribution of inactivation times. Principal component analysis revealed that UV-C effectiveness was associated to low particle size, a⃰, turbidity and high UV-C transmittance. An increase on the inactivation of treated bacterial populations was recorded along storage, while no yeast recovery was observed, thus emphasizing the contribution of refrigerated storage to microbial inactivation. Microbial inactivation in clear and turbid juices achieved by UV-C (390 mJ/cm²) assisted by mild heat (50 °C) and subsequent refrigerated storage may represent an useful alternative for multiple applications in the juice industry.

消费者对高质量和安全食品和饮料的需求不断增长，激发了人们对替代保存技术的兴趣。与传统的热处理相比，短波长紫外光（UV-C，254 nm）已被证明可用于净化各种澄清果汁，同时提高其质量。混浊汁液中的悬浮固体和有色化合物会降低透光率。在障碍方法下使用UV-C可能是一种有前途的治疗策略。这项研究的目的是分析大肠杆菌ATCC 25922，酿酒酵母KE 162和植物乳杆菌ATCC 8014的失活在清晰梨汁（PJ），混浊的橙桔（OT）和橙香蕉芒果猕猴桃草莓（OBMKS）果汁通过单UV-C（390毫焦耳/厘米处理²，20℃）和UV-C在盘管装置中以中试规模的适度加热（UV-C / H，50°C）辅助，并在冷藏（5°C）下存储。还在蛋白ept水（PW）和模型溶液（MS）中进行了灭活研究。研究了Coroller，Weibull和Biphasic Plus Shoulder模型的充分性。UV-C在PW，MS和PJ中非常有效，可将植物乳杆菌，大肠杆菌和酿酒酵母的对数减少多达5.5-6.3-4.7、4.8-5.1-4.6和4.4-5.5 ，分别。而在混浊混合物中，单个UV-C导致中等程度的灭活，在OT和OBMKS中分别减少了2.4-3.8-1.6和3.6-3.7-1.3对数循环。当进行UV-C / H处理时，观察到高度的细菌灭活分别使OT，OBMKS和PJ的对数降低5.2-5.6、6.3-6.6和5.5-6.7，而酵母的对数降低4.6-4.9。分别在OBMKS和OT中。因此，观察到UV-C和H之间的加成灭活作用。测试的所有模型均提供了有关耐药性不同的微生物亚群的存在的有用信息。然而，累积的威布尔分布函数是最通用的函数，拟合具有不同形状的失活曲线。另外，电阻的频率分布表明，UV-C / H不仅增强了UV-C的杀菌作用，而且改变了灭活时间的分布。主成分分析表明，UV-C的有效性与低粒径有关，a，浊度高，UV-C透射率高。在存储过程中记录了处理过的细菌种群灭活的增加，而没有观察到酵母的回收​​，因此强调了冷藏存储对微生物灭活的贡献。通过UV-C（390 mJ / cm ²），温和的热量（50°C）辅助实现的澄清和混浊果汁中的微生物失活以及随后的冷藏储存，可能是果汁行业中多种应用的有用替代方法。