Intervention Technologies to Enhance the Microbiological Safety of Fresh Produce

增强生鲜农产品微生物安全的干预技术

• 批准号: RGPIN-2014-06092
• 负责人: Warriner, Keith
• 金额: $ 1.89万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567589
• 关键词: Intervention; Technologies; Enhance; Microbiological; Safety

The number of recalls and foodborne illness outbreaks linked to fresh fruit and vegetables continues to increase. Most noteworthy have been outbreaks of foodborne illness linked to lettuce and cantaloupes which appear especially susceptible to contamination. To date, the main approach has been to focus food safety initiatives at the primary production stage and also at the post-harvest wash stage that is designed to remove field acquired contamination. Although primary production initiatives such as the leafy greens agreement have enhanced food safety standards the open nature of crop production makes it impossible to prevent contamination. In a similar manner, it is well established that post-harvest washing is limited (1-2 log cfu reduction at best) and poses a greater risk of cross-contaminating produce rather than decontamination. The proposed research program will be directed towards developing post-harvest interventions to enhance the microbiological safety of fresh produce through decontamination and prevention of cross-contamination thereby meeting a Food Safety Objective of a 5 log cfu reduction of relevant pathogens. The first stage will reduce contamination of produce during holding and transport by introducing antimicrobial hydroxyl radicals into the headspace. Hydroxy radicals generated do not have strong antimicrobial activity but can inactivate pathogens over long exposure periods hence compatible with storage and transport of fresh produce. Cross-contamination events up to the wash step will minimized through in-process decontamination technologies using electrolyzed water or UV:hydrogen peroxide (Advanced Oxidative Process). Both approaches have the benefits of potent antimicrobial activity without producing significant disinfection byproducts. The surfaces will focus on conveyors and slicing units which are established cross-contamination sites. Although a degree of decontamination is expected in the wash water the main aim is to reduce cross-contamination events through using a novel acidified chitosan based sanitizer that will inactivate pathogens and also coagulate organic loading. Finally, a post-wash decontamination step based on using Advanced Oxidative Process will be applied to remove residual pathogen levels. Here, the research will be directed towards developing a continuous AOP treatment unit to build on the success achieved using a batch reactor. The reactor will be based on a UV tunnel with hydrogen peroxide mist being introduced into the headspace. Each intervention will be optimized in terms of pathogen (five stain cocktail of Salmonella, Shiga Toxin Producing Escherichia coli and Listeria monocytogenes) reduction whilst maintaining product quality (visual, texture). Each intervention will be optimized in terms of maximal log count reduction with no detrimental effects on product quality. The research will benefit the industry by reducing the incidence of pathogens on fresh produce. Although the current study will focus on lettuce and cantaloupes it can be envisaged that the same approach could be applied to other produce types. Moreover, the intervention steps will be optimized and critical limits established to facilitate a true HACCP system. The technologies being applied are currently available or near market so can be readily implemented by the fresh produce industry.

与新鲜水果和蔬菜有关的召回和食源性疾病爆发的数量继续增加。最值得注意的是与莴苣和哈密瓜有关的食源性疾病的爆发，这些食物似乎特别容易受到污染。到目前为止，主要的方法是将食品安全举措的重点放在初级生产阶段以及旨在去除现场获得的污染的收获后清洗阶段。虽然绿叶蔬菜协议等初级生产倡议提高了食品安全标准，但作物生产的开放性使其不可能防止污染。以类似的方式，已经确定收获后洗涤是有限的（最多减少1-2 log cfu），并且造成交叉污染农产品的风险更大，而不是去污。拟议的研究计划将针对开发收获后的干预措施，以通过去污和防止交叉污染来提高新鲜农产品的微生物安全性，从而达到相关病原体减少5个对数cfu的食品安全目标。第一阶段将通过向顶部空间引入抗微生物羟基自由基来减少保存和运输过程中的产品污染。产生的羟基自由基没有很强的抗菌活性，但可以在长时间暴露后杀灭病原体，因此与新鲜农产品的储存和运输相容。通过使用电解水或UV：过氧化氢（高级氧化工艺）的过程中净化技术，将最大限度地减少清洗步骤前的交叉污染事件。这两种方法都具有有效的抗微生物活性而不产生显著的消毒副产物的益处。表面将集中在输送机和切片单位，这是建立交叉污染的网站。虽然洗涤水中预期有一定程度的净化，但主要目的是通过使用新型酸化壳聚糖基消毒剂来减少交叉污染事件，该消毒剂将杀灭病原体并还凝结有机物负载。最后，将应用基于高级氧化工艺的清洗后去污步骤，以去除残留病原体水平。在这里，研究将针对开发一个连续的AOP处理单元，以建立在使用间歇反应器取得的成功。反应器将基于紫外线隧道，过氧化氢雾被引入顶部空间。将在减少病原体（沙门氏菌、产滋贺毒素大肠杆菌和单核细胞增生李斯特菌的五种混合菌）的同时优化每种干预措施，同时保持产品质量（外观、质地）。每种干预措施都将在最大对数计数减少方面进行优化，对产品质量没有不利影响。这项研究将通过减少新鲜农产品上病原体的发生率而使该行业受益。虽然目前的研究将集中在生菜和哈密瓜，但可以设想，同样的方法可以适用于其他农产品类型。此外，将优化干预步骤，并建立关键限值，以促进真正的HACCP系统。所应用的技术目前可用或接近市场，因此可以很容易地由新鲜农产品行业实施。