Antimicrobial gas phase treatments for apples and other moisture sensitive produce to enhance food safety and shelf-life

最近爆发的与受污染的糖果苹果有关的李斯特菌病导致34例确诊病例和3例死亡。此次暴发突显了农产品对污染的敏感性，需要采取干预措施来灭活田间获得的污染。用来生产糖果苹果的苹果面临的挑战是，这个过程需要干苹果来确保焦糖涂层的粘附性。无论如何，洗涤在减少病原体方面的效果已被证明是有限的。拟议的项目将证明组合抗菌气体处理的原理，以灭活完整苹果水果上和水果内的病原体(李斯特氏菌、大肠杆菌和沙门氏菌)。将要研究的气体将包括臭氧、二氧化氯和羟基自由基。气体处理将被纳入苹果的预处理过程 从而将水果提高到加工温度。在这里，装在手提箱里的苹果被堆放在一起，然后引入气流来去除表面的水分。气体处理将根据气体浓度、成分、时间和相对湿度进行优化。以实验室为基础的研究将确定在保持水果质量的同时，支持病原体和腐败微生物减少5log所需的工艺条件。这些研究将得到工厂内验证试验的补充。这项即将开发的技术还可以应用于其他对水分敏感的农产品，如软果、嫩果和蘑菇等。

The recent outbreak of listeriosis linked to contaminated candy apples results in 34 confirmed cases and 3 deaths. The outbreak underlined the susceptibility of produce to contamination and need for intervention steps to inactivate field acquired contamination. The challenge with apples destined for candy apple production is the process requires dry apples to ensure adherence of the caramel coating. In any event, washing has been demonstrated to have limited efficacy with respect to pathogen reduction. The proposed project will demonstrate proof-of-principle of combination of antimicrobial gas treatments to inactivate pathogens (Listeria, E. coli and Salmonella) on and within intact apple fruit. The gases to be studied will include ozone, chlorine dioxide and hydroxyl radicals. The gas treatment will be incorporated into apple pre-conditioning process whereby the fruit are raised to processing temperature. Here, the apples within totes are stacked then an air stream introduced to remove surface moisture. The gas treatments will be optimized with respect to gas concentration, composition, time and relative humidity. Laboratory based studies will determine the process conditions required to support a 5 log reduction of pathogens and spoilage microbes whilst retaining fruit quality. The studies will be supplemented with in-plant verification trials. The technology to be developed can be applied to other water sensitive produce such as soft fruit, tender fruit and mushrooms, in addition to others.