Control of Listeria monocytogenes in the fresh produce supply chain (CASE project).

新鲜农产品（沙拉和香草）被认为是健康营养饮食的必需品，但在农场和工厂可能受到环境污染。由于新鲜农产品没有煮熟，潜在的健康风险会加剧。特别令人关注的是新鲜农产品被单核细胞增生李斯特菌污染，这种病原体仅导致少数食源性暴发，但它会导致严重的胃肠道感染，对免疫功能低下的患者非常虚弱，导致孕妇流产，在所有主要食源性病原体中死亡率最高。它广泛存在于土壤和水中，可以在一系列温度下生长，包括在食品加工和储存过程中发现的4摄氏度的低温。我们发现它在温度范围内形成单一培养的生物膜，并可以根据营养物质的可用性、温度和消毒压力变成可存活但不可培养的（VBNC）。VBNC表型意味着使用ISO批准的金标准培养恢复方法会遗漏它的存在，如果食品被认为不含病原体，则会带来公共卫生风险。关于其在食品供应链中存在的多微生物生物膜群落（微生物组）中存活的能力，以及相互作用如何支持病原体持久性，包括对食品工业经常使用的杀菌剂的抗菌素耐药性，以及在存在或不存在杀菌剂的情况下的VBNC状态，人们知之甚少。目标是：开发适当的样品回收和分子方法来检测微生物组和可培养的和VBNC L.单核细胞增生在供应链的关键点。确定支持单核增生乳杆菌在供应链中持续存在的可能的协同或拮抗相互作用。使用适当的微生物组和单核增生乳杆菌的工厂生物膜实验室模型，确定工厂清洁的适当消毒程序。验证实验室研究与现场工厂测试合适的消毒剂，以确定现实生活中的安全操作条件。

Fresh produce (salads and herbs) are considered essential for a healthy nutritious diet but may be exposed to environmental contamination in the farm and factory. Potential health risk is exacerbated due to fresh produce not being cooked. Of particular concern is contamination of fresh produce with Listeria monocytogenes, a pathogen responsible for only a small number of foodborne outbreaks but it causes a serious gastrointestinal infection which can be extremely debilitating for immunocompromised patients, causes miscarriage in pregnant women and has the highest mortality of all the major foodborne pathogens. It is widely found in soil and water and can grow over a range of temperatures, including chill temperatures of 4oC which are found in food processing and storage. We showed it forms monoculture biofilms over the temperature range and can become viable but nonculturable (VBNC) depending on nutrient availability, temperature and disinfection stress. The VBNC phenotype means that its presence is missed using the ISO approved, gold standard culture recovery methods, presenting a public health risk if food is deemed free of pathogens. Little is known about its ability to survive in polymicrobial biofilm communities (microbiomes) present in food supply chains and how interactions may support pathogen persistence, antimicrobial resistance including to sanitisers regularly used by the food industry, and the VBNC state in the presence or absence of sanitisers. The aims are:Develop appropriate sample recovery and molecular methods to detect microbiomes and culturable and VBNC L. monocytogenes at critical points in the supply chain.Determine possible synergistic or antagonistic interactions in supporting L. monocytogenes persistence in the supply chain.Determine appropriate sanitisation procedures for factory cleaning using appropriate laboratory models of factory biofilms of microbiomes and L. monocytogenes.Validate lab studies with on-site factory testing of suitable sanitisers to determine real life safe operating conditions.