When food goes bad: understanding biofilm formation to prevent food spoilage

世界上近10%的人口没有足够的食物。由于预计到2050年全球人口将增加到98亿，我们需要将粮食供应水平提高至少50%，才能养活世界人口。一个被提出的解决方案是减少粮食损失和浪费（FLW），因为据估计，全世界供人类消费的粮食总量中约有三分之一被损失或浪费。造成FLW的一个主要原因是微生物的腐败。鉴于这些惊人的数字，许多政府和全球组织正在采取多管齐下的方法，以确保我们能够在未来几十年养活全世界。事实上，了解导致食品腐败的生物过程的重要性符合BBSRC的战略挑战“3.2.1生物科学促进可持续农业和粮食”和响应模式优先事项“减少食物链中的浪费”。微生物（细菌、病毒和真菌）生长在食物表面或食物链的表面，形成一种叫做生物膜的粘稠膜。生物膜无处不在，从浴室水槽、淋浴间和冰箱上形成的黏液沉积物，到自然界中池塘或岩石上的黏液。粘稠的涂层起到了保护层的作用，使得在生物膜中杀死微生物和在生物膜形成后物理去除生物膜变得非常困难。导致一系列肉类、乳制品和蔬菜产品变质的主要细菌群被广泛称为假单胞菌。当你冰箱里的食物变质，你把它扔掉时，很可能是由于这些细菌在变质的沙拉叶、肉或变质牛奶中的聚集体上的生物膜中生长。在英国，每个成年人平均损失或浪费280公斤的食物，这大约占全球食物总量的20%。仅在英国，每年就有670万吨或15.2万卡车的食物被浪费。目前还没有直接针对食物表面形成的生物膜来延长食物的保质期或阻止食物变质的策略。总的来说，本奖学金的工作旨在：1。确定我们是否可以阻止假单胞菌物种在食物上形成生物膜，通过靶向生物膜粘稠部分的共同成分，细胞外DNA （eDNA）。许多细菌在生物膜黏液中含有eDNA，它为生物膜提供强度和结构，并帮助生物膜抵抗去除它的企图。我的初步数据显示假单胞菌物种生物膜中存在eDNA。我能接触到一种叫NucB的酶，它能分解eDNA。在这项工作中，我将测试将NucB放在食物表面是否会阻止细菌形成生物膜，以及我是否可以去除已经在食物上形成的生物膜。2. 了解假单胞菌如何在食物的生物膜中生长，从而导致食物变质。通过详细了解这一过程，我们将能够开发新的方法来阻止食品上或食物链表面（例如食品加工厂或食品包装上）形成生物膜，以延长保质期并减少食品腐败。这项工作可以直接转化为减少食物上细菌生长的解决方案，从而减少食物腐败。此外，本研究项目开发的技术将对了解其他细菌（例如导致食物中毒的细菌）如何通过食物链传播非常有用。

Almost 10% of the world's population do not get enough to eat. Since the global population is predicted to rise to 9.8 billion by 2050, we need to increase levels of food availability by at least 50% to be able to feed the world's population. One proposed solution has been to reduce food loss and wastage (FLW), since it is estimated that around 1/3 of the total food produced for human consumption worldwide is either lost or wasted. A major contributor to FLW is spoilage by microbes. Given these drastic numbers, many governments and global organisations are adopting a multi-pronged approach to ensure we can feed the world over the coming decades. Indeed, the importance of understanding biological processes that lead to food spoilage falls within the BBSRC's Strategic Challenge '3.2.1 Bioscience for Sustainable Agriculture and Food' and the Responsive Mode Priority of 'Reducing Waste in the Food Chain'.Microbes (bacteria, viruses and fungi) grow on the surfaces of food, or on surfaces in the food chain, in a slimy film called a biofilm. Biofilms are found everywhere, from the slimy deposits that form on the bathroom sink, shower and fridge, to the slime seen in ponds or on rocks in nature. The slimy coating acts as a protective layer, making it very difficult to kill microbes when they are in biofilms and to physically remove the biofilm once it has formed. A major group of bacteria that cause spoilage of a range of meat, dairy and vegetable products are broadly called Pseudomonas species. When food in your fridge goes off and you throw it out, it is very likely to be due to these bacteria growing in biofilms on spoiled salad leaves, meat or on the aggregates in spoiled milk. On average 280 kg of food is lost or wasted per adult in the UK, which contributes to approx. 6.7 million tonnes, or 152,000 full lorries, of food wasted each year in the UK alone. There are currently no strategies that directly target biofilm formation on food surfaces to either extend the shelf life of food or stop food spoilage. Overall, the work in this Fellowship aims to: 1. Determine if we can stop Pseudomonas species forming biofilms on food by targeting a common component of the slimy part of biofilms, extracellular DNA (eDNA). Many bacteria have eDNA in the biofilm slime, which provides strength and structure to the biofilm and helps the biofilm resist attempts to remove it. My preliminary data shows that there is eDNA in Pseudomonas species biofilms. I have access to an enzyme called NucB, which can break down eDNA. In this work I will test if putting NucB on food surfaces stops bacteria forming biofilms and if I can remove a biofilm that is already formed on food with NucB. 2. Understand how Pseudomonas species grow in biofilms on food to bring about food spoilage. By understanding this process in detail, we will then be able to develop new ways to stop biofilms forming on food, or on surfaces in the food chain (e.g. in food processing plants or on food packaging) to extend the shelf-life and reduce food spoilage. This work could be directly translated into solutions to reduce the growth of bacteria on food and thus food spoilage. Additionally, the techniques developed in this Fellowship will be very useful in understanding how other bacteria, for instance those that cause food poisoning, are transmitted through the food chain.