Institute of Agri-Food & Land Use

Coordinator:  Dr Irene Grant

Foodborne illness continues to be a global public health/food safety issue and the focus of much research.  Both known and emerging human pathogens demand attention.  When pathogens emerge and begin to cause human illness research is urgently needed to fill knowledge gaps in several key areas: detection methods, microbial ecology, pathogenicity, growth characteristics, survival characteristics and control options.  Research within IAFLU is focusing on emerging pathogens of human and animal health significance that are either foodborne or present in the environment.  One pathogen of particular interest is Mycobacterium avium subsp. paratuberculosis (MAP), the cause of Johne’s disease in animals, which may also have some association with Crohn's disease in humans.  It may be transmitted to humans through foods derived from animals infected by the organism, particularly dairy products, and it can also persist in the farm environment for lengthy periods and contaminate water sources. Dr Irene Grant has extensive research experience and publications in this area.  Research to develop more rapid and reliable detection methods for MAP is urgently needed so that the full extent of food and environmental contamination by this pathogen can be accurately assessed.  Research on several other pathogens (Enterobacter sakazakii, Campylobacter jejuni, Clostridium sp. and Cryptosporidium spp.) will be undertaken and microbiology expertise within IAFLU is also being utilised to determine if any of the growing number of candidate ‘natural antibiotics’ could be effective in reducing the need for antimicrobial therapy in farm animals.

The Problem

In relation to MAP we know that MAP is shed in the milk of dairy cattle with Johne's disease but the true extent of MAP contamination of dairy products is not known because it cannot be accurately assessed due to deficiencies in existing detection methods, so better detection methods for MAP in terms of specificity and speed are an urgent requirement.  In relation to the other pathogens information needs to be quickly generated by research in many areas so that appropriate control measures can be identified and put in place to reduce their public health impact.

Pathogen research within IAFLU

Research within IAFLU is currently focusing on the following:

• Prevalence of MAP in dairy products (cheese and milk-based infant formula)
• Development of improved methods for the isolation and detection of MAP in food matrices (PhD: Antonio Foddai)
• Investigation of the fate of MAP and other pathogens present in dairy wastewater in a constructed wetland system  (PhD: Janette-Louise Brettell)
• Assessment of the impact of 'natural antibiotics' on pathogens of animal health significance (PhD: Stella Wong)
• Investigation of the impact of food preservation technologies on emerging pathogens

The Anticipated Outcomes

• Successful development of a more rapid and specific method for detection of viable MAP involving immunomagnetic separation and phage amplification which would have application to food, water and animal testing
• Identification of naturally occurring antimicrobials that could be added to animal feedingstuffs to potentially replace antibiotic therapy for farm animals