The project focuses on addressing the rise of foodborne illnesses linked to ready-to-eat salads, particularly caused by zoonotic pathogens like Shiga toxin-producing E. coli (STEC). These pathogens are responsible for approximately 500,000 cases annually in the UK, costing £1.8 billion. A recent outbreak of STEC tied to contaminated lettuce highlighted the need for faster and more efficient contamination detection methods. Current detection methods in the UK rely on ISO standards, taking2-3 days to confirm contamination. This delay often allows contaminated produce to reach consumers, increasing health risks and economic losses due to product recalls. Furthermore, testing facilities are limited, especially during outbreaks, reinforcing the urgent need for quicker detection tools to protect public health and the economy. The situation is worsened by climate change. The Food Standards Authority (FSA)has noted that rising temperatures, along with extreme weather events such as floods and droughts, are facilitating the spread of pathogens like STEC across agricultural fields. These environmental changes pose an increasing risk to food safety, necessitating more timely and effective detection methods. One promising solution for early contamination detection is the profiling of volatile organic compounds (VOCs), which are produced by both plants and microorganisms. VOC profiling can detect subtle metabolic changes in plants caused by bacterial colonisation, identifying contamination before visible signs appear. While prior research has shown success in detecting pathogens like E. coli in various settings, further work is needed to assess its potential for detecting STEC in salad leaves and its broader industrial application. The project aims to develop a rapid, cost-effective VOC-based detection system that can be integrated into the food supply chain. By combining dual transcriptome insights with an understanding of climate change's effects on contamination, the research will advance both detection capabilities and knowledge of plant-pathogen interactions.

The project is structured around three objectives:

1. Sensitivity, Specificity, and Enrichment : The detection limits of VOC profiling will be determined, assessing whether the VOCs are specific to STEC contamination. Different concentrations of STEC O157will be tested on lettuce, alongside other bacterial strains. VOCs will be collected and analysed using gas chromatography and mass spectrometry, simulating various stages of the food supply chain. The project will also explore enhancing sensitivity by introducing exogenous metabolites that interact with bacterial enzymes, potentially increasing detectable VOC production.

2. Reproducibility and Climate Impact : The consistency of VOC profiles will be assessed across various growing seasons and environmental conditions, considering factors such as temperature, humidity, and light mimicking the impact of global warming on bacterial colonisation and VOC detection efficiency.

3. Plant Response to Colonisation: By examining the molecular interaction between STEC and salad leaves, this objective will analyse gene expression in both plants and bacteria. This dual transcriptome analysis will identify plant defence mechanisms and potential contamination markers informing future detection strategies.

The student will receive comprehensive interdisciplinary training, gaining expertise in microbiology, plant science, analytical chemistry, and bioinformatics. Collaborating with industry leaders like the Food Standards Agency (FSA), the student will participate in bi-monthly meetings, interact with industrial partners, and engage with real-world food safety challenges. Additionally, the student will be supported to attend national and international conferences and short visits to our collaborator at QUB, enhancing both their academic and professional development in the rapidly evolving field of food safety.

How to Apply

For student application, here is the link to the online application survey; https://app.onlinesurveys.jisc.ac.uk/s/cardiff/onezoo-cdt-student-applications-for-2024-25 . If the application meets the entrance requirements, the applicant will be invited to an interview. Only successful applicants will then go on and apply to the institution. Instructions for that will be provided after the interview. Information on the application process can also be found on the website www.onezoo.uk.

Guidance on the application and interview process of the OneZoo CDT can be found here: How to improve your application & interview skills

A copy of the student application survey can be found here: Student Application Form OneZoo CDT 2024. This is provided to give you an idea of the information required and the points that need to be addressed.