Exploration of high voltage atmospheric cold plasma as a practical tool for reducing food spoilage

这项研究计划旨在建立介质阻挡放电高压大气冷等离子体(HVACP)的潜力，以比现有处理和洗涤更少的能源和水来显著改善食品安全和延长食品保质期，从而实现更可持续和更环保的制造工艺。在接下来的五年资助期内，我们建议开展三个平行的研究轨道，目的是扩大对高压大气冷等离子体(HVACP)的科学认识，并展示其作为一种实际干预技术的潜在应用，以改善食品安全和质量。轨道1将深入研究以空气为填充气体的HVACP在50千伏以上电压下的气体等离子体产生特性以及由此产生的活性气体物种(RGS)的产生和这些RGS在储存过程中的稳定性，以潜在地提高安全性和延长新鲜食品的保质期。轨道2将考察在不同的HVACP电压和处理时间下，改性气体混合物(即，CO2、N2、O2、H2、Ne)的RGS生成化学。以前的工作已经证明，随着电压的变化，气体组成会改变RGS，这可以在不改变绿叶蔬菜等敏感食品质量的情况下延长货架期。第三个轨道将是对HVACP处理的优化，以延长番茄等新鲜农产品的保质期，并对处理后的食品进行质量、安全和毒理学评估。只需使用空气和少量电力(100瓦或更少)即可产生暖通空调。使用空气作为填充气体，在80千伏时将产生大约5,000 ppm的活性氮和活性氧物种。对于许多新鲜农产品应用，用空气进行HVACP处理是一种低成本的选择，并且有利于延长保质期和提高安全性。然而，一些产品，如绿叶蔬菜，可能会受到空气中产生的RGS的影响，因此，希望使用混合气体的HVACP处理来创建更有益的RGS配置文件。通过改变HVACP气体组成，RGS的数量和类型可以增加到30,000 ppm以上，并创建独特的气体化学(“签名”)。假设这些量身定做的HVACP气体化学药剂可以提供非热RGS处理，可以选择性地瞄准并销毁细菌、酵母、霉菌、真菌毒素、化学污染物、酶或病毒，而不会损害新鲜农产品或产生有毒化合物。这三个研究轨道的成功完成将实现扩大对HVACP的科学理解的总体目标，展示其作为提高食品安全和质量的实际干预技术的潜在应用，可能会导致更广泛的行业采用和新鲜水果和蔬菜保鲜方法的革命性变化。

This research program aims to build on previous work establishing the potential for a dielectric barrier discharge high voltage atmospheric cold plasma (HVACP) to deliver significant improvement in food safety and extension of food shelf-life with much less energy and water requirements than existing treatments and washes leading to a more sustainable and environmentally friendly manufacturing process. In the next five-year funding period, we propose to engage in the three parallel research tracks with the goal of expanding the scientific understanding of high voltage atmospheric cold plasma (HVACP) and demonstrate its potential application as a practical intervention technology for improving food safety and quality. Track 1 will be an in-depth mechanistic study of the HVACP utilizing air as the fill gas at voltages above 50 kV on the gas plasma generation characteristics and the resulting reactive gas species (RGS) generation and the stability of these RGS during storage to potentially improve safety and extend shelf-life fresh foods. Track 2 will be an examination of RGS generation chemistry for modified gas blends (i.e., CO2, N2, O2, H2, Ne) under different HVACP voltages and treatment times. Previous work has demonstrated that changing gas composition along with voltage changes RGS which can achieve shelf-life extension with no quality change on sensitive foods such as leafy greens. Track 3 will be optimization of HVACP treatment to extend the shelf-life of fresh produce, such as tomatoes, and provide an evaluation of quality, safety, and toxicology of treated food. HVACP can be generated using only air and a small amount of electricity (100 W or less). Using air as the fill gas will generate approximately 5,000 ppm of reactive nitrogen and reactive oxygen species at 80 kV. For many fresh produce applications HVACP treatment with air is a low cost option and is beneficial for extending shelf-life and improving safety. However some products, such as leafy greens, can be impacted by the RGS generated in air and therefore utilization of HVACP treatment using gas blends is desirable to create more beneficial RGS profiles. By changing HVACP gas composition the number and type of RGS can be increased to over 30,000 ppm and create unique gas chemistries (`signatures'). The hypothesis is that these tailored HVACP gas chemistries can deliver non-thermal RGS treatments that can selectively target and destroy bacteria, yeast, molds, mycotoxins, chemical contaminants, enzymes, or viruses without damaging the fresh produce or producing toxic compounds. The successful completion of these three research tracks will achieve the overall goal of expanding scientific understanding of HVACP, and demonstration of its potential application as a practical intervention technology for improving food safety and quality will potentially lead to broader industry adoption and a revolutionary change to preservation methods of fresh fruit and vegetables.