1 Centro Nacional de Ciencia y Tecnología de Alimentos (CITA), Universidad de Costa Rica (UCR), Ciudad Universitaria Rodrigo Facio, Código postal 11501-2060, San José, Costa Rica.
2 Department of Food Science, Cornell University, 630 West North Street, Geneva, New York 14456, USA.
J Food Prot. 2018 Sep;81(9):1549-1556. doi: 10.4315/0362-028X.JFP-18-085.
The growing demand for fruit and vegetable juice blends, with improved nutritional and sensory attributes, has prompted the industrial adoption of nonthermal processing technologies, including UV light. Limited studies have explored conditions to overcome the well-known limitations of UV when treating liquid foods with a high content of particles that absorb or scatter UV light. This study addressed the effectiveness of the application of UV light, using a commercial processing unit, to inactivate pathogenic Escherichia coli O157:H7, Salmonella enterica (hereafter Salmonella), and Listeria monocytogenes, as well as spoilage microorganisms, in colored and turbid juices and beverages. The inactivation of cocktails of five strains (or serotypes) of E. coli O157:H7, Salmonella, and L. monocytogenes isolated from fruit- and vegetable-derived products linked to outbreaks was determined in seven colored and turbid cold-pressed juices and beverages. Juices and beverages were UV treated at a constant flow rate of 150 L/h through multiple consecutive passes. The inactivation of aerobic mesophilic bacteria, molds and yeasts, and lactic acid bacteria was also assessed at the cumulative dose that guaranteed a 5-log reduction of the most UV-tolerant pathogen for each product. A 5-log reduction of the three pathogens was achieved in all juices and beverages at a maximum cumulative UV dose of 12.0 ± 0.6 mJ/cm. The dose required to ensure the targeted reduction varied depending on the tested product and the inoculated pathogen. The reduction of aerobic mesophiles, molds and yeasts, and lactic acid bacteria varied from 0.5 to 3.6, from 0.2 to 2.0, and from 0.5 to 3.6 log CFU/mL, respectively. Thus, the proposed treatment represents a suitable processing alternative to ensure the safety and extend the shelf life of colored and turbid cold-pressed juices and beverages.
对具有改善营养和感官特性的水果和蔬菜汁混合物的需求不断增长，促使工业采用非热加工技术，包括紫外线 (UV)。有限的研究探索了在处理含有大量吸收或散射 UV 光的颗粒的液体食品时克服 UV 已知局限性的条件。本研究使用商业加工单元研究了应用 UV 光的效果，以灭活致病性大肠杆菌 O157:H7、沙门氏菌（以下简称沙门氏菌）和单核细胞增生李斯特菌以及变质微生物在彩色混浊果汁和饮料中。在七种彩色混浊冷榨果汁和饮料中，测定了从与暴发相关的水果和蔬菜衍生产品中分离出的五种大肠杆菌 O157:H7、沙门氏菌和单核细胞增生李斯特菌菌株（或血清型）鸡尾酒的灭活情况。果汁和饮料以 150 L/h 的恒定流速通过多次连续通过进行 UV 处理。还评估了好氧嗜温细菌、霉菌和酵母菌以及乳酸菌在保证每种产品最耐 UV 病原体减少 5 个对数的累积剂量下的失活情况。在所有果汁和饮料中，在最大累积 UV 剂量为 12.0 ± 0.6 mJ/cm 时，三种病原体均减少了 5 个对数。确保目标减少所需的剂量取决于测试产品和接种的病原体。好氧嗜温菌、霉菌和酵母菌以及乳酸菌的减少量分别为 0.5 至 3.6、0.2 至 2.0 和 0.5 至 3.6 log CFU/mL。因此，所提出的处理方法代表了一种合适的加工替代方案，可以确保彩色混浊冷榨果汁和饮料的安全性并延长保质期。
