Antimicrobials

Anti-microbial agents (bacteriophage and bacteriocins) for control of verocytotoxigenic E. coli at key stages in the beef chain

E.coli O157:H7 and other verocytotoxigenic E. coli (VTEC) are significant food borne pathogens and cattle and derived beef and beef products are significant vectors of these organisms as evidenced by recent outbreaks across Europe. Recent quantitative risk assessments on E. coli O157 :H7 in minced beef have demonstrated that the factors having the largest impact on predicted risk of illness are the numbers of E. coli O157:H7 on the faeces / hide of the animal presented for slaughter and the concentration of the pathogen in beef products. An intervention to reduce numbers of the pathogen at either of these key points in the beef chain would yield a significant risk reduction. Biocontrol agents including bacteriocins (anti-microbial peptides) and bacteriophage now offer huge potential as innovative, novel control agents in beef production and processing. These agents can specifically inhibit bacteria but have no impact on human or animals. This project will assess whether selected bacteriophage and bacteriocins can be applied to reduce numbers of E. coli O157:H7 at key points in the beef chain namely to reduce shedding of the pathogen in cattle or to reduce its numbers in beef products. These biocontrol agents will also be fully characterised to determine their mode of action. (kaye.burgess@teagasc.ie) or (geraldine.duffy@teagasc.ie )

Safety of functional foods: Assessment and critical evaluation of antibiotic resistance transfer in the food chain

This project has demonstrated horizontal gene transfer (HGT) of antibiotic encoding genes between different types of lactic acid bacteria (LAB) in laboratory, plant and animal (rumen) systems. HGT on antibiotic genes has also been discovered to occur between LAB donors and pathogenic bacterial recipients including Salmonella spp., Escherichia coli, Staphylococcus aureus and Listeria monocytogenes using a filter mating system. Current research will determine whether or not HGT between these organisms can occur in food systems such as yogurt. The results of this research suggest that LAB strains used in the functional foods sector should be tested for the presence of antibiotic resistance encoding genes and their potential transfer to other bacteria assessed before application in the food industry. (declan.bolton@teagasc.ie)

Nutraceutical and functional food bioactive peptides in beef, bovine offals and fermented meat products.

This project will harvest bioactive compounds from beef and bovine offals for use as food ingredients to protect against coronary heart disease, cancer and food poisoning. Three approaches are being used including;

• digestion of crude muscle and offal tissue with proteases;
• extraction of proteins, semi-purification and digestion with proteases and
• fermentation of bovine muscle and offals.

The peptides produced will be assayed, extracted, purified and characterised. This project will deliver high value added products from meat. (declan.bolton@teagasc.ie) or (anne.mullen@teagasc.ie)