• Antibiotic resistance in foodborne pathogens

      Duffy, Geraldine; Walsh, Ciara (Teagasc, 2005-02)
      Wide-spread antibiotic resistance among bacterial pathogens is now a serious public health issue and multi-antibiotic resistance has been reported in many foodborne pathogens including Salmonella and E. coli.
    • Automated detection and characterisation of foodborne pathogens

      Duffy, Geraldine; O'Hanlon, Karen; Catarame, Terese; Smyth, Davida S.; McCann, Máiréad (Teagasc, 2007-06)
      This study focused on the development of molecular tools for the rapid detection and characterisation of food-borne pathogens including Verocytotoxigenic Escherichia coli (VTEC) (serotypes O157, O26 and O111) and Salmonella spp. The study involved the development of enrichment systems and the identification of unique genetic targets in these pathogens which could be amplified and detected by Real Time Polymerase Chain Reaction (PCR).
    • Control and detection of food-borne pathogens

      Duffy, Geraldine; Cloak, Orla; Sheridan, James J.; Department of Agriculture, Food and the Marine, Ireland (Teagasc, Ballsbridge, Dublin 4, 1998-08)
      The objective of this study was to develop rapid methods for the detection of bacteria from food.
    • Development of a critical control step for E.coli 0157:H7 in pepperoni

      Duffy, Geraldine; Riordan, Denise C.; Sheridan, James J.; US-Ireland Co-operation Programme in Agriculture Science and Technology (Teagasc, 1999-10)
      Verocytotoxin producing Escherichia coli (VTEC) and particularly strains of serogroup O157, have emerged as food poisoning pathogens which can cause a severe and potentially fatal illness. The symptoms of VTEC infection include haemorrhagic colitis with bloody diarrhoea and severe abdominal pain. The infection may lead to renal failure as a result of haemolytic uraemic syndrome. Because of the severity of the illness and the low infectious dose, this pathogen is classed as a serious food safety issue. It is recommended by the United States Department of Agriculture that the production process for ready to eat foods such as fermented meats (pepperoni, salami etc.) should be capable of addressing a worst case scenario ie. the production process should be able to yield a log105.0cfu /g (105 cfu/g) reduction in numbers of E. coli O157:H7 on the raw meat. The aim of this study was to develop an industrially viable critical control step(s) which could be implemented into the pepperoni production process.
    • A European study on animal food & biomedical aspects of E.coli 0157:H7

      Duffy, Geraldine; Garvey, Patricia; Sheridan, James J.; European Union; CT98-3935 (Teagasc, 2002-02)
      Verocytotoxin producing Escherichia coli (VTEC) and, in particular, strains of serogroup O157, have emerged as significant pathogens causing a range of severe and potentially fatal illnesses. The European Union has recognised the threat posed by E coli O157:H7 and the need to devise control strategies based on an understanding of VTEC pathogenicity, transmission, survival and growth. It acknowledges the importance of informing farmers, veterinarians, food producers and health authorities so that each of these groups can act appropriately to reduce the overall hazards posed by these organisms. To contribute to the development and dissemination of effective control strategies, the European Commission funded this Concerted Action Project 1
    • A nationwide surveillance study on E.coli 0157:H7 and enterobacteriaceae in Irish minced beef products

      Duffy, Geraldine; Cagney, Claire; Crowley, Helen; Sheridan, James J.; Food Safety Authority of Ireland (Teagasc, 2003-04)
      A surveillance study on prevalence and numbers of E . coli O157: H7 in minced beef (unpackaged or packaged) and beefburgers (frozen, fresh and unpackaged or packaged) was carried out over a period of 12 months in the Republic of Ireland. A total of 1533 products were tested with approximately 15 products collected from each of the 26 counties every 3 months. Mince and beefburgers were collected from both supermarkets and butcher shop outlets. A standard analysis was conducted by sample enrichment, IMS extraction and plating onto SMAC agar with confirmation by PCR. The results showed that 43 retail beef products (2.8 %) contained E .coli O157:H7. The number of E .coli O157: H7 in 21 of these samples ranged from log100.51 - 4.03 cfu g-1 ( i.e. 3 to 10,700 bacteria per gram) while in the remaining 22 the pathogen was detectable by enrichment only. There was a seasonal effect observed with 33 of 43 positive samples detected in January (n = 8), April /May(n=20) and August (n=5) and the remaining 10 positive samples detected over the other 8 months. Of the beef products testing positive, 32 were purchased from supermarkets and 11 from butcher shops. E .coli O157:H7 was recovered from 2.8% (13 / 457) of fresh packaged mince and from 1.88 % (3 / 160) of fresh unpackaged burgers purchased from butcher shops. Of the 43 isolates recovered, 41 contained the virulence genes v t1, v t2, E aeA and H lyA while the remaining 2 isolates contained only one of the vtproducing genes (v t1or v t2).
    • A quantitative risk assessment of E.coli 0157:H7 in Irish minced beef

      Duffy, Geraldine; O'Brien, Stephen; Carney, Eimear; Butler, Francis; Cummins, Enda; Nally, Padraig; Mahon, Denise; Henchion, Maeve; Cowan, Cathal (Teagasc, 2005-02)
      A national quantitative risk assessment was undertaken for minced beef in the Republic of Ireland. The objective was to estimate the probability of E. coli O157:H7 infection from consumption of Irish beef and to investigate the parts of the beef chain contributing most to the risk posed by this pathogen.The quantitative risk assessment was broken into 3 main modules: 1) production of boxed beef trimmings; 2) processing of trimmings and burger formation and 3) retail/domestic consumption phase. Key points in each module (beef hide, beef trimmings and beef products at retail) were validated using data derived from microbiology sampling at beef abattoirs, supermarkets and butchers’ shops in Ireland.
    • Recovery and identification of emerging Campylobacteraceae from food

      Duffy, Geraldine; Cagney, Claire; Lynch, Orla; Downey, Gerard (Teagasc, 01/02/2007)
      The family Campylobacteraceae includes 23 different species of Campylobacter and Arcobacter.To date, clinical and epidemiological interest has focused almost exclusively on just two of these species, C. jejuni and C. coli. Current routine examination methods for both clinical and food samples look exclusively for these two species. Recent clinical research indicates that some of the other, previously ignored Campylobacter species may be linked to human infection. The focus of this research was to develop a routine procedure which would allow recovery of all 23 species of Campylobacteraceae from food samples.
    • Routine diagnostic tests for food-borne pathogens

      Duffy, Geraldine; Kilbride, Brendan; Fitzmaurice, Justine; Sheridan, James J. (Teagasc, 2001-01)
      Rapid techniques were developed and applied to the determination of total viable bacteria and to the detection of food borne pathogens (Listeria monocytogenes, Salmonella, Campylobacter jejuni and E. coli O157:H7). The method developed for total viable counts is based on membrane filtration and fluorescent staining and the technique can be performed and a result obtained within 20 min. The results correlate well with the standard plate count and the technique is now being implemented in Irish food factories.
    • A study of cryptosporidium parvum in beef

      Duffy, Geraldine; McEvoy, John M.; Moriarty, Elaine M.; Sheridan, James J.; European Union; QLK1 CT 1999 00775 (Teagasc, 2003-07)
      There is increasing concern that foods, particularly those of animal origin, may play a role in the transmission of C ryptosporidium parvum to humans. Studies were undertaken to examine the risk posed by C . parvum in the beef chain.
    • Tracking of Salmonella through the Pork Slaughter Process

      Prendergast, Deirdre M.; Duggan, Sharon J.; Duffy, Geraldine; Downey, Gerard; Safefood; National Development Plan 2007-2013 (Teagasc, 01/10/2009)
      To help address the problem of salmonellosis in the Republic of Ireland (RoI), a national Salmonella control programme was introduced in 1997 with a view to reducing the prevalence of Salmonella in pigs on the farm and on pig carcasses. The primary objective of this present study was to determine the correlation between the Salmonella serological and bacteriological status of pigs presented for slaughter and the Salmonella status of pork cuts following slaughter, dressing and chilling. Two additional studies investigated the prevalence and numbers of Salmonella spp. in the boning halls of four commercial pork abattoirs and at retail level in butcher shops and supermarkets in the RoI. The results indicated that categorisation of pig herds on the basis of a historical serological test for Salmonella was not a good predictor of the bacteriological Salmonella status of individual pigs at time of slaughter. However, it is acknowledged that serological testing does help in giving a rough estimate of the overall Salmonella status of a pig herd. There was a linear correlation between prevalence of Salmonella in caecal contents and on pork cuts at factory level; therefore, if the number of herds presented for slaughter with high levels of Salmonella (category 3) was reduced, there would be less potential for contamination of the lairage, equipment etc. and so less likelihood of Salmonella contamination on pork. The impact of crosscontamination during transport, lairage, processing and distribution cannot be ignored and measures to diminish this would significantly reduce the dissemination of Salmonella in the chain and the consequent risk posed. A key finding was the considerable variation in the incidence of Salmonella on different sampling days and in different slaughter plants.