The consumption of ready-to-eat fresh produce raises the issue of food-borne pathogen infections; thus, disinfecting ready-to-eat produce for commercial use, such as in homes and restaurants, is important to ensure food safety. Chemical sanitizers are typically used for disinfection. Ultraviolet-light emitting diodes (UV-LEDs) are a novel non-thermal disinfection technology that consumes less energy and generates less heat than traditional UV lamps, making them more appealing to consumers. In this study, we combined ultrasonic (US) washing method with UV-LEDs (US-UV-LEDs) to develop a technique for disinfecting fresh produce without using chemical sanitizers and compared its efficacy with three common household sanitizers (“84” (sodium hypochlorite) disinfectant, kettle descaler (citric acid), and vinegar (acetic acid)). In addition, we investigated the efficacy of this method in controlling pathogen numbers in the water used to wash (washing water) the produce to prevent cross-contamination between water and produce. Cherry tomatoes and lettuce were selected as produce models and Typhimurium and O157:H7 were used as the bacterial models. The results showed that US-UV-LEDs reduced the numbers of Typhimurium and O157:H7 on produce by 2.1–2.2 log CFU/g, consistent with the results achieved by the three household sanitizers; however, kettle descaler and vinegar had a limited effect (2.6–3.5 log CFU/mL) on residual pathogens in the washing water. Furthermore, we created washing water with low (754 mg/L) and high (1425 mg/L) chemical oxygen demand (COD) levels and determined the disinfection efficacy of “84” disinfectant and US-UV-LEDs. The results showed that US-UV-LEDs reduced the number of Typhimurium and O157:H7 by 2.0–2.1 and 1.8–2.1 log CFU/g under low and high COD levels, respectively, which was similar a result to that of “84” disinfectant. However, the residual pathogen numbers in the washing water were reduced to 1.4–1.9 log CFU/mL after treatment with US-UV-LED under high COD, whereas the pathogens were undetected in the washing water disinfected with “84” disinfectant. These results suggest that US-UV-LEDs have better application potential than acidic household sanitizers, but chlorine sanitizer remains the most effective disinfecting method.

中文翻译：

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使用超声波清洗与 UV-LED 相结合作为一种新颖的无化学方法对新鲜即食产品进行消毒


即食新鲜农产品的消费引发了食源性病原体感染的问题；因此，对家庭和餐馆等商业用途的即食产品进行消毒对于确保食品安全非常重要。化学消毒剂通常用于消毒。紫外线发光二极管（UV-LED）是一种新型非热消毒技术，与传统紫外线灯相比，其能耗更低、产生的热量更少，因此对消费者更具吸引力。在本研究中，我们将超声波（US）清洗方法与紫外线 LED（US-UV-LED）相结合，开发了一种无需使用化学消毒剂即可对新鲜农产品进行消毒的技术，并将其与三种常见家用消毒剂（“84”（钠）次氯酸盐）消毒剂、水壶除垢剂（柠檬酸）和醋（醋酸））。此外，我们还研究了该方法在控制用于清洗农产品的水中（洗涤水）中的病原体数量以防止水和农产品之间的交叉污染方面的功效。选择樱桃番茄和生菜作为农产品模型，使用鼠伤寒菌和 O157:H7 作为细菌模型。结果表明，US-UV-LED 将农产品中的鼠伤寒菌和 O157:H7 数量减少了 2.1-2.2 log CFU/g，与三种家用消毒剂所取得的结果一致；然而，水壶除垢剂和醋对洗涤水中残留病原体的影响有限（2.6-3.5 log CFU/mL）。此外，我们还制备了低（754 mg/L）和高（1425 mg/L）化学需氧量 (COD) 水平的洗涤水，并确定了“84”消毒剂和 US-UV-LED 的消毒效果。结果表明，US-UV-LED 使鼠伤寒菌和 O157:H7 的数量减少了 2.0-2.1 和 1.8-2。在低COD水平和高COD水平下分别为1 log CFU/g，与“84”消毒剂的结果相似。然而，在高COD下经US-UV-LED处理后，洗涤水中的残留病原体数量降低至1.4-1.9 log CFU/mL，而用“84”消毒剂消毒的洗涤水中未检测到病原体。这些结果表明，US-UV-LED 比酸性家用消毒剂具有更好的应用潜力，但含氯消毒剂仍然是最有效的消毒方法。