Paper-based platform for on site, rapid, and multiplexed DNA-based pathogen detection in aquaculture

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Shellfish has the potential to become one of the largest future mainstream food in the UK due to its health, ethical and sustainable benefits. Oysters, mussels and clams are recognised as environmentally friendly and sustainable compared to other types of farming. In the UK, the shellfish sector was worth £11.7 million in 2016 with a signification growth of 60% in the past 10 years, reaching its highest level of 7,732 tonnes in 2016. Shellfish is also a sustainable food source. They do not require feeding, as they filter nutrients from the water around them. More importantly, contrary to fish, they do not require space or enrichment in order to grow, and their farmed habitat is similar to their wild habitat. They also often do not require much cooking, e.g. oysters are often eaten raw. However, this latter advantage leads to a historical issue in the shellfish industry: the product has a very short lifecyle. To ensure the product is safe for consumption, food safety programmes perform extensive testing on shellfish to detect human pathogens that could have accumulated from contamination of the water (since shellfish feed by filtering the water, pathogens such as Salmonella or norovirus can accumulate even if they are at low concentration in the water). The conventional testing procedures however are time-consuming and laborious, and require the access to sophisticated laboratory facilities. When the results of the test are finally obtained, the shellfish has been already consumed, which limits the implementation of any preventive action. This resulted in nearly 1 million cases of food poisoning in the UK in 2011, leading to about 11 million lost working days. In this project, we will develop and implement a low-cost technique, which has been developed for the detection of human and animal pathogens in low-resource settings, such as in the field in Uganda and in a farm in India, for the rapid detection of pathogens in seawater in aquaculture. Together with our partners the Centre for Environment, Fisheries and Aquaculture Sciences Cefas (the world leader in marine science and technology) and Cromarty Mussels Ltd (the largest single site for both mussel and oyster farming in Scotland), we will develop deployable paper-based biosensor devices (lab-on-a-paper) for the online monitoring of seawater and the detection of foodborne pathogens. The platform relies on the enrichment of pathogens from seawater using a combination of filtration and magnetic beads in a syringe, onto a paper-based biosensor. By folding the paper, in a process akin to origami, the genetic material of the pathogens is purified and distributed into specific areas, where nucleic acids are amplified. This amplification (performed using a small hand-held heater with low power at around 60C, but could also be performed in a thermos) is then detected using either direct visualisation of a color change or using a mobile phone for quantification, within 1h. Used in farms, the platform will allow the rapid detection of 3 pathogens, Salmonella and two types of norovirus, which are the most common pathogens associated with illness from shellfish consumption. Together with our partners, we will test the performance of the devices in the field in a shellfish farm, in Inverness. These results will then enable the consortium to progress towards developing this as a product for the industry to be able to rapidly respond to contamination events, so that consumer safety is assured, and shellfish aquaculture can grow to its full potential. Deployed within the environment, this platform also has the potential to serve as an early warning system of contamination events and to enable source disease tracking and thus risk prediction.