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Irish Microbial Risk Assessment Network

Dr. Geraldine Duffy

Contact Details:

Dr. Geraldine Duffy
Tel: +353 (0)1 8059554
Email: geraldine.duffy@teagasc.ie
Qualifications: B.Sc (UCD) Grad Diploma in Food Science (D.I.T. Kevin St.), PhD (University of Ulster) 
Institute: Ashtown Food Research Centre


Areas of Expertise:

  • Rapid diagnostic methods for food pathogens
  • Verocytotoxigenic E. coli
  • Cryptosporidium parvum
  • Quantitative risk assessment for food pathogens
  • Antibiotic resistance of food pathogens
  • Campylobacter


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Research Projects:

  • Verocytotoxigenic E.coli (including E coli O157:H7) in beef and beef products
  • Automated diagnostic tests for foodborne pathogens
  • Antibiotic resistance and the survival of antibiotic resistant Campylobacter, Salmonella and E.coli O157:H7 in foods and processing
  • Development of rapid nucleic acid based methods and demonstration of equivalence with cultural techniques for assessing compliance with forthcoming EU microbiological criteria for fresh meat carcasses
  • Detection and surveillance of Enterobacter sakazakii along the infant formula food chain
  • Prevalence and epidemiology of emergent strains of verocytotoxigenic Escherichia coli (O157, O26 and O111) in Irish food animals at the pre-harvest and harvest levels of the food chain
    Public health significance of emergent Campylobacter and Arcobacter spp. in the Irish food chain
  • Anti-microbial agents (bacteriophage and bacteriocins) for control of verocytotoxigenic E. coli at key stages in the beef chain
  • Application of biotechnology to control of spoilage and foodborne pathogens on meat.
  • Research network on Verocytotoxigenic E. coli in Ireland
  • Occurrence of Salmonella on pork on the island of Ireland and an assessment of the risk factors contributing to its transmission
  • Foodborne zoonosis: a co-ordinated food chain approach
  • Additional Projects: · Improved physiological, immunological and molecular tools for the recovery and identification of emerging campylobacteriaceae in the food and water chain. Funded by EU Framework (Start date November, 2002 End date November 2005)
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Research Documents

  • Duggan, S.J., Prendergast, D.M., Leonard, N., Mannion, C., Butler, F., Fanning, S. and Duffy, G. (2007) Tracking of Salmonella positive pigs from farm to fork in the republic of Ireland. Proceedings of the 7th International symposium on the epidemiology and control of foodborne pathogens in pork. Verona, Italy 9-11 May Session 2: Epidemiology, pp 91-94

  • Duggan, S., Prendergast, D., Butler, F., Leonard, N., Mannion, C., Fanning, S. and Duffy, G. (2007) Society for General Microgiology. 161st Meeting 3-6th September 2007, University of Edinburgh. p. 67

  • Nally, P., Cummins, E.J., Butler, F., Prendergast, D., Duggan, S. and Duffy, G. (2006). Development of a preliminary quantitative exposure assessment model for Salmonella spp. during pork slaughter in the Republic of Ireland. Proceedings of EU Cost 920 Meeting, Britanny, France September

  • Prendergast, D.M., Duggan, S.J., and Duffy, G. (2006) Risk analysis based control of Salmonella on pork cuts on the island of Ireland. Proceedings of the 52nd International Congress of Meat Science and Technology (ICoMST), Harnessing and Exploiting Global Opportunities, University College Dublin, Ireland. 13th – 18th August. Pages 299-300

  • Mannion, C., Leonard, F.C., Duggan, S., Prendergast, D., Egan, J. and Duffy, G. (2006) The prevalence of Salmonella in pigs from farm to fork in Ireland. Proceedings of the Association for Veterinary Teaching and Research Work, 60th Annual Meeting, Royal Hotel, Scarborough, 10th-12th April.

  • Duggan, S.J., Prendergast, D.M. , Fanning, S. and Duffy, G. (2006) A quantitative risk assessment on Salmonella on pork on the island of Ireland: Sensitivity of microbiological method used to generate exposure assessment data. Proceeding of the 13S International Symposium on Salmonella and Salmonellosis, May 10-12, Saint-Malo, France, Page 569

  • Nally, P., Cummins, E.J., Butler, F., Prendergast, D., Duggan, S. and Duffy. G. (2006) A draft exposure assessment of Salmonella spp. in pork cuts in Irish abattoirs. Biosystems Engineering Research Review II, University College Dublin, Ireland. May 2006. Pages 106 – 112.

  • Nally, P. Cummins, E.J., Butler, F., Duggan, S., Prendergast, D. and Duffy. G. (2006) Development of a preliminary quantitative exposure assessment model for Salmonella spp. during pork slaughter in the Republic of Ireland. Proceedings of MEDVETNET Meeting, Malta, May

  • NFC No 74 - A Quantitative Risk Assessment of E.coli O157:H7 in Irish Minced Beef - Geraldine Duffy, Stephen O'Brien, Eimear Carney, Francis Butler, Enda Cummins, Padraig Nally, Denise Mahon, Maeve Henchion, Cathal Cowan - Ashtown Food Research Center (2005) - Teagasc Final Report. ISBN: 1 84170 431 8

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  • Duggan, S., Prendergast, D., Butler, F., Cummins, E.,, Nally, P., Leonard, N., Mannion, C., Fanning, S., Madden, B., Naughton, P. and Duffy, G. (2005) Occurrence of Salmonella on pork on the island of Ireland and an assessment of the risk factors contributing to its transmission. Proceedings of the International Conference: The Science of Food Safety and Nutrition, Croke Park Stadium, Dublin, 1st – 2nd December p:130

  • Carney, E., O'Brien, S., Sheridan, J.J., McDowell, D.A., Blair, I.S. and Duffy, G. (2005). Prevalence and level of Escherichia coli O157:H7 on beef trimmings, carcasses and boned head meat at a beef slaugfhtering plant. Food Microbiology 23: 52-59 ISSN 0740-0020 10917 A1

  • O'Brien, S., Duffy, G., Carney, E., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (2005). Prevalence and numbers of Escherichia coli O157:H7 on bovine hides at a beef slaughter plant. Journal of Food Protection 68 (4): 660-665 10920 A1

  • Moriarty, E.M., Duffy, G., McEvoy, J.M., Caccio, S., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (2005). The effect of thermal treatments on the viability and infectivity of Cryptosporidium parvum on beef surfaces. Journal of Applied Microbiology 98, 618-623 ISSN 1364-5072 10655 A1

  • Duffy, G., O'Brien, S., Carney, E., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (2005). Characterisation of E. coli O157:H7 isolates from bovine hide and beef trimming in Irish abattoirs by pulsed field gel electrophoresis. Journal of Microbiological Methods 60, 375-382 10658 A1

  • O'Hanlon, K., Catarame, T, Sheridan, J.J., Blair, I.S., McDowell, D.A. and Duffy, G. (2005). Comparison of a real-time PCR and an IMS/cultural method to detect VTEC O26 and O111 in minced beef in the Republic of Ireland. Food Microbiology 22: 553-560 ISSN 0740-0020 11675

  • McEvoy, J.M., Duffy, G., Moriarty, E.M., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (2005). The prevalence and characterisation of Cryptosporidium spp. in beef abattoir water supplies. Water Research 39: 3697-3703 ISSN ISSN 0043-1354 11674 A1

  • Crowley, H., Cagney, C., Sheridan, J.J., Anderson, W., McDowell, D.A., Blair, I.S., Bishop, R.H. and Duffy, G. (2005). Enterobacteriaceae in beef prodeucts from retail outlets in the Republic of Ireland and comparison of the presence and counts of E. coli O157:H7 in these products. Food Microbiology 22, 409-414 ISSN 0740-0020 10657 A1

  • Hocquette, J.F., Richardson, R.I., Prache, S., Medale, F., Duffy, G. and Scollan, N.D. (2005). The future trends for research on quality and safety of animal products. Italian Journal of Animal Science 4 (3): 49-72 ISSN 1594-4077 11673 A1

  • Walsh, C., Duffy, G., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (2005). Thermal resistance of antibiotic-resistant and antibiotic-sensitive Salmonella spp on chicken meat. Journal of Food Safety 25: 288-302 ISSN 01 49 6085 11678 A1

  • NFC No 76 - Antibiotic Resistance in Foodborne Pathogens - Geraldine Duffy, Ciara Walsh, Ashtown Food Research Centre (2005) - Teagasc End of Project Report, ISBN: 1 84170 433 4

  • Auty, M., Duffy, G., O'Beirne, D., McGovern, A., Gleeson, E. and Jordan, K.N. (2005). In situ localization of Escherichia coli O157:H7 in food by confocal scanning laser microscopy. Journal of Food Protection 68: (3), 482-486 10649 A1

  • O'Brien, S., Duffy, G., Sheridan, J.J., Blair, I.S. and McDowell, D.A. (2005). Detection and recovery rates achieved using direct plate and enrichment / immunomagnetic separation methods for Escherichia coli O157:H7 in minced beef and on bovine hide. Letters in Applied Microbiology 41: 88-93 ISSN 0266-8254 10919 A1

  • Moriarty, E.M., McEvoy, J.M., Lowery, C.J., Thompson, H.P.,, Finn, M., Sheridan, J.J., Blair, I.S., McDonnell, D.A. and Duffy, G. (2005). Prevalence and characterisation of Cryptosporidium species in cattle faeces and on beef carcasses at slaughter. Journal of Applied Microbiology 98, 618-623

  • Fitzmaurice, J., Glennon, M., Duffy, G., Sheridan, J.J., Carroll, C. and Maher, S. (2004). Real-time qualitative and quantitative assays for the detection and quantification of VT 1 ad VT 2 in E. coli O157:H7. Molecular Microbiology 18: 123-132 9817

  • O'Keeffe, M., Danaher, M., Downey, G., Duffy, G. and Henchion, M. (2004). Review of the Assessment of the Results under Contract Nos. B6-7920/98/000016-000023, 000034. Food and Veterinary Offic 100 pp 9400

  • Moriarty, E.M, McEvoy, J.M., Duffy, G., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (2004). Development of a novel method for isolating and detecting Cryptosporidium parvum from lean and fat beef carcass surfaces. Food Microbiology 21: 275-282 ISSN 0740-0020 9816

  • O'Hanlon, K., Catarame, T.M.G., Duffy, G., Sheridan, J.J., Blair, I.S. and McDowell D.A. (2004). Rapid detection and quantification of E. coli O157:H7 / O26 / 111 in minced beef by real-time PCR. Journal of Applied Microbiology 96: 1013-1023 ISSN 1364-5072 9815

  • McEvoy, J.M., Duffy, G., Moriarty, E.M., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (2004). Effect of a commercial freeze / tempering process on the viability of Cryptosporidium parvum occysts on lean and fat beef trimmings. Meat Science 67: 559-564 ISSN 0309-1740 9818

  • NFC No 62 - A Study of Cryptosporidium Parvum in Beef - Duffy G., McEvoy J., Moriarty E.M., Sheridan J.J. - ISBN 1 84170 337 0

  • A quantitative exposure assessment of Escherichia coli O157:H7 in Irish retail beef products - P. Nally, E. Cummins, F. Butler, S. O’Brien, G. Duffy, E. Carney, and J.J. Sheridan

  • Duffy, G. (2003). Survival and persistence of verocytotoxigenic E. coli in faeces and manure. Journal of Applied Microbiology 94: 94S-103S ISSN 1364-5072

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  • Catarame, T, O'Hanlon, K., Duffy, G., Sheridan, J.J., Blair, I.S. and McDowell, D.A. (2003). Optimisation of enrichment and plating procedures for the recovery of E. coli 0111 and 026 from minced beef. Journal of Applied Microbiology 95: 949-957 ISSN 1364-5072

  • NFC No 63 - A Nationwide Surveillance Study on E.coli 0157:H7 and Enterobacteriaceae in Irish Minced Beef Products - Duffy G., Cagney C., Crowley H., Sheridan J.J. ISBN: 1 84170 338 9

  • Catarame, T., O'Hanlon, K. and Duffy, G. (2002 - Development of a selective enrichment broth for Escherichia coli 026 and 011 - ISSN 0791-6833

  • Walsh, C., Duffy, G. (2002) - Antibiotic Resistance Profiles of Irish Isolates of Salmonellae and Verocytotoxigenic E.coli - 32nd Annual Food Science and Technology Conference, UCC

  • Moriarty, E.M., McEvoy, J.M., Duffy, G. and Sheridan, J.J. (2002) - A method to isolate and detect Cryptosporidium parvum from beef - ISSN 0791-6833

  • NFC No 51 - A European Study on Animal, Food and Biomedical Aspects of E. coli 0157:H7 - Duffy G., Garvey P., Sheridan J.J. (2002) - Teagasc Final Report, ISBN 1 84170 278 1

  • NFC No 31 - Routine Diagnostic Tests For Food-borne Pathogens - Duffy, G., Kilbride, B., Fitzmaurice, J. and Sheridan, J. (2001) - Teagasc Final Report, ISBN 1 84170 189 0.

  • Walsh, D., Duffy, G., Sheridan, J.J., Blair, I.S. and McDowell, D.A. (2001). Antibiotic resistance among Listeria, including Listeria monocytogenes in retail foods. Journal of Applied Microbiology 90: 4, 517-522 ISSN 1364-5072

  • Duffy, G., Garvey, P., McDowell, D.A., Coia, J. and Wasteson, Y. (2001). Control of Verocytotoxigenic E. coli. Special Edition of. International Journal of Food Microbiology 66: 1-2 ISSN 0168-1605

  • Cloak, O.M., Duffy, G., Sheridan, J.J., Blair, I.S. and McDowell, D.A. (2001). Incidence of Campylobacter in Irish retail meats and a surface adhesion-PCR method for its detection from food. Food Microbiology 18: 287-298 ISSN 0740-0020

  • Walsh, D., Duffy, G., Sheridan, J.J., Blair, I.S., McDowell, D.A. and Harrington, D. (2001). Thermal resistance of wild type and antibiotic resistant Listeria monocytogenes in meat and potato substrates. Journal of Applied Microbiology 90: 4, 555-560 ISSN 1364-5072

  • Duffy, G., Walsh, D., Sheridan, J.J., Logue, C., Harrington, D., Blair, I.S. and McDowell, D.A. (2001). Comparison of selective and non-selective enrichment media in the detection of L. monocytogenes from meat containng L. innocua. Journal of Applied Microbiology 90: 6, 994-999 ISSN 1364-5072

  • Duffy, G., Garvey, P. and Sheridan, J.J. (2000). E. coli 0157:H7: A European Perspective. Irish Journal of Agricultural & Food Research 39: 173-182 ISSN 0791-6833

  • Riordan, D.C.R., Duffy, G., Sheridan, J.J., Whiting, R.C., Blair, I.S. and McDowell, D.A. (2000). The effect of acid adaptation, product pH and heating on the survival of Escherichia coli 0157:H7 in pepperoni. Applied Environmental Microbiology 1726-1729 ISSN 0099-2240

  • Duffy, G., Riordan, D.C.R., Sheridan, J.J., Call, J.E., Whiting, R.C., Blair, I.S. and McDowell, D.A. (2000). Effect of pH on survival, thermotolerance and verotoxin production of E. coli 0157:H7 during simulated fermentation and storage. Journal of Food Protection 63: 12-18

  • Duffy, G., Kilbride, B, Sheridan, J.J., Blair, I.S. and McDowell, D.A. (2000). A membrane-immunofluorescent-viability staining technique for the detection of Salmonella spp. from fresh and processed meat samples. Journal of Applied Microbiology 89: 587-594 ISSN 1364-5072

  • Duffy, G., Whiting, R.C. and Sheridan, J.J. (1999). The effect of competitive microflora, pH and temperature on the growth kinetics of Escherichia coli 0157:H7. Food Microbiology 16: 299-307 ISSN 0740-0020

  • Duffy, G., Cloak, O.M., Sheridan, J.J., Blair, I.S. and McDowell, D.A. (1999). The development of a combined surface adhesion and polymerase chain reaction (PCR) technique for the rapid detection of Listeria monocytogenes in meat and poultry. International Journal of Food Microbiology 49: 151-159 ISSN 0168-1605

  • Cloak, O.M., Duffy, G. and Sheridan, J.J. (1999). Development of a surface adhesion immunofluorescent technique for the rapid detection of Salmonella spp. from meat and poultry. Journal of Applied Microbiology 86: 583-590 ISSN 1364-5072

  • Duffy, G. and Sheridan, J.J. (1999). Effect of pH and culture composition on the adhesion of plasmid bearing and plasmid cured Yersinia enterocolitica to a polycarbonate membrane in a rapid surface adhesion immunofluorescent technique. Journal of Applied Microbiology 86: 867-873 ISSN 1364-5072

  • Duffy, G., Riordan, N. Denise, C.R, Sheridan, J.J., Whiting, R.C., Eblen, B.S., Miller, A.M., McDowell, D.A. and Blair, I.S. (1999). Differences in thermotolerance of Escherichia coli 0157:H7 strains in a salami matrix. Food Microbiology 16: 83-91 ISSN 0740-0020

  • Cloak, O.M., Duffy, G., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (1999). Simultaneous isolation of three pathogens, S. enteritidis, L. monocytogenes and Y. enterocolitica using a surface adhesion immunofluorescent technique. Journal of Microbiological Methods 39: 33-43

  • NFC No 18 - Development of a critical control step for E.coli O157:H7 in pepperoni - Duffy, G., Riordan, D. and Sheridan, J. (1999) - Teagasc Final Report, ISBN 1 84170 079 7

  • Duffy, G., Cloak, O.M., O Sullivan, M.G., Guillet, A., Sheridan, J.J., Blair, I.S. and McDowell, D.A. (1999). The incidence and antibiotic resistance profiles of Salmonella spp. on Irish retail meat products. Food Microbiology 16: 623-631 ISSN 0740-0020

  • Duffy, G. (1999). An EU Concerted Action on verocytotoxigenic E. coli. International Food Safety News 8: 2-4

  • NFC No 03 - Control and detection of foodborne pathogens - Duffy, G., Cloak, O. and Sheridan, J.J. (1998) - Teagasc Final Report, ISBN 1 901138429

  • Walsh, D., Duffy, G., Sheridan, J.J., McDowell, D.A. and Blair, I.S. (1998). Comparison of a selective and non-selective broth for the isolation of Listeria spp. from retail foods. Journal of Food Safety 18(2): 85-101 ISSN 0149 6085

  • Riordan, D., Duffy, G., Sheridan, J.J., Whiting, R.L., Eblen, B.S., McDowell, D.A. and Blair, I.S. (1998). Survival of E. coli 0157:H7 in fermented meats. Journal of Food Protection 61(2): 146-151

  • Duffy, G. and Sheridan, J.J. (1998). Viability staining in a direct count rapid method for the determination of total viable counts on processed meats. Journal of Microbiological Methods 31: 167-174

  • Duffy, G. and Sheridan, J.J. (1997). The effect of temperature, pH and medium on the adhesion of Listeria monocytogenes to a membrane. Journal of Applied Microbiology 83: 1, 95-102 ISSN 1364-5072

  • Sheridan, J.J., Duffy, G., McDowell, D.A. and Blair, I.S. (1997). Development of a surface adhesion immunofluorescent microscopy technique for the rapid detection of Listeria monocytogenes and Listeria innocua from raw meat. Journal of Applied Microbiology 82(2): 225-233 ISSN 1364-5072

  • Duffy, G., Sheridan, J.J., Hofstra, H., McDowell, D.A. and Blair, I.S. (1997). A comparison of an immunomagnetic immunofluorescent technique and a surface adhesion immunofluorescent technique for the detection of Listeria monocytogenes and Listeria innocua from meat. Letters in Applied Microbiology 24(6): 445-451 ISSN 0266-8254

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