EnvironSafe: Cold Plasma Innovations for Food Safety and Sustainability

等离子体被认为是物质的第四种状态，与固体，液体和气体并列。等离子体是部分或完全电离的气体，在自然界中占可观测宇宙的99%以上，包括太阳，极光（北方光），闪电和家庭照明。当气体被提供有足够的能量时，例如通过添加热能或在强电场的影响下电离，形成等离子体。等离子体已经广泛用于微电子工业和消毒应用，但这些等离子体是在低压下产生的，并达到非常高的温度（热等离子体）。在室温或接近室温下产生等离子体的能力，称为非热或“冷”等离子体，已导致用于治疗人类疾病的广泛应用，这是一个称为等离子体医学的新领域。冷等离子体在环境温度和压力下产生丰富的化学环境，其主要由称为活性氧和氮物质（RONS）的化学物质组成，其与真核和原核生物形式相互作用。这使得它们可用于治疗细菌感染，其中它们显示出快速和广谱的活性，以及用于一些人类疾病，其中它们可以改变患病组织（例如局部癌症和伤口）。由于冷等离子体产生的丰富的化学环境，细菌中的多个靶标被修饰，这意味着不太可能出现耐药性。此外，等离子体化学具有中和和改变一系列化学试剂的能力，例如蛋白质、毒素、酶、过敏原和小分子，这些化学试剂可能进入人类食物链并引起疾病。因此，在本研究提案中，我们将设计、构建、验证和测试等离子体发生装置，用于一系列应用，其中我们将直接将样品暴露于等离子体或在液体中产生等离子体，并测试“等离子体活化液体”（帕尔斯）的活性。研究的总体目标是开发等离子体处理系统，能够快速有效地中和从食品加工到准备食用的任何环节可能进入食物链的人类健康风险。这些风险包括细菌生物膜，细菌生物膜是在表面上形成的细菌群落，并将自己包裹在粘稠的基质中，使得难以使用食品工业中常用的标准化学消毒剂去除或破坏它们。将测试等离子体去除这些生物膜或削弱它们的能力，以使它们能够使用低得多的剂量的抗微生物剂（杀生物剂）根除。此外，我们已经证明等离子体可以中和某些化学试剂，例如酶和其他蛋白质和小分子（抗生素，细菌信号分子），因此，等离子体也可以用于从食物链中去除对人类健康构成风险的化学试剂，例如微生物和过敏原的毒素。然而，重要的是要了解和验证冷等离子体与细菌，人体细胞和各种化学制剂的生物和化学相互作用，这些化学制剂被确定为食物链中的风险。我们将使用先进的物理、生物和化学分析技术来解决这些重要问题。通过这种方式，使用等离子体来净化食品加工、制造和制备的关键区域可以从食物链中去除关键的微生物和化学制剂，这将增加食品的寿命并减少浪费，并提高食物链的安全性和可持续性。这有可能通过减少食源性疾病和条件，减少食品制备，加工和分销中的浪费，并提高英国，爱尔兰和全球农业食品部门的盈利能力，对改善健康产生重大影响。

Plasmas are regarded as the fourth state of matter, alongside solids, liquids and gases. Plasmas are partially or completely ionised gases and in nature make up over 99% of the observable universe, including the sun, the aurora (northern lights), lightening and domestic lighting. Plasmas form when gases are provided with sufficient energy, for example by addition of thermal energy or under the influence of a strong electric field, to ionise. Plasmas are already used widely in teh microelectronics industry and for sterilisation applications, but these plasmas are generated under low pressure and reach very high temperatures (thermal plasmas). The ability to generate plasmas at or near room temperature, known as non-thermal or 'cold' plasmas, has led to a wide range of applications for treatment of human diseases, a new field known as plasma medicine. Cold plasmas generate a rich chemical environment at ambient temperatures and pressures which is mainly comprised of chemical species known as reactive oxygen and nitrogen species (RONS), which interact with eukaryotic and prokaryotic forms of life. This makes them useful for the treatment of bacterial infections, where they show rapid and broad spectrum activity, and for some human diseases where they can modify diseased tissues (such as topical cancers and wounds). Because of the rich chemical environment generated by cold plasmas, multiple targets in bacteria are modified, meaning that resistance us unlikely to emerge. In addition, the plasma chemistry has the ability to neutralise and modify a range of chemical agents such as proteins, toxins, enzymes, allergens and small molecules which may enter the human food chain and cause diseases. Therefore, in this research proposal we will design, construct, characterise and test plasma generating devices for use in a range of applications where we will either directly expose samples to plasma or generate plasmas in liquids and test the activity of the 'plasma activated liquids' (PALs). The overall aim of the research is to develop plasma treatment systems which are able to rapidly and effectively neutralise risks to human health which can enter the food chain at any point from processing of food to its preparation for consumption. These risks include bacterial biofilms which are bacterial communities which form on surfaces and encase themselves in a slimy matrix, making it difficult to remove or destroy them using standard chemical disinfectants which are commonly used in the food industry. Plasmas will be tested for their ability to remove these biofilms or to weaken them to the extent that they can be eradicated using much lower doses of antimicrobial agents (biocides). In addition, we have shown that plasmas can neutralise certain chemical agents, such as enzymes and other proteins and small molecules (antibiotics, bacterial signalling molecules), therefore, plasmas may also be useful in removing chemical agents from the food chain which pose a risk to human health such as toxins from microorganisms and allergens. However, it is important to understand and characterise biological and chemical interactions of cold plasma with bacteria, human cells and the various chemical agents identified as risks in the food chain. We will use advanced physical, biological and chemical analysis techniques to a dress these important questions. In this way, the use of plasmas to decontaminate critical areas for food processing, manufacture and preparation may remove critical microbiological and chemical agents from the food chain which will increase the longevity of food products and reduce waste, and improve the safety and sustainability of the food chain. This has the potential to have significant impact in improving health by reducing food borne diseases and conditions, reduce waste in the preparation, processing and distribution of food products and improve the profitability of the Agri-Food sector in the United Kingdom, Ireland and globally.