• The Development and/or Validation of Novel Intervention Technologies to Assure Meat Food Safety

      Bolton, Declan J.; Byrne, Brian; Lyng, James; Downey, Gerard (Teagasc, 01/02/2007)
      This project was undertaken to fill some of the knowledge gaps in meat food safety from farm to fork. The data provide the scientific basis for a clean sheep policy to reduce the impact of fleece as a source of microbial contamination on ovine carcasses at the beginning of the slaughter process. At the other end of the slaughter-line, a polyurethane sponge swabbing technology was developed for ovine and bovine carcass sampling as required in 2001/471/EC and the new European Commission Hygiene Regulations. At the processing stages, studies were undertaken to determine the most effective media for the recovery and culture of Cl. perfringens cells and spores; the results were then applied to thermal inactivation studies on these bacteria. Thermal resistance data were also obtained for Bacillus cereus and a radio frequency cook for meat products was validated in terms of the destruction of Cl. perfringens and B. cereus cells and spores. Finally, an aerobiology study investigated the effectiveness of a range on measures to prevent air acting as a vector for bacterial dispersion in a meat processing plant.
    • A Risk Assessment and Hazard Analysis and Critical Control Point (HACCP) Study for the Irish Catering Industry

      Bolton, Declan J.; Meally, Aisling; Downey, Gerard (Teagasc, 01/02/2007)
      This report provides details of a food safety knowledge survey, a microbiological survey, a chilled temperature survey and an audit conducted in 200 restaurants throughout the island of Ireland. The results suggest a low incidence of several bacterial pathogens (including Salmonella enterica) and identify areas in which food safety knowledge, procedures and practices should be improved. Salmonella enterica isolates were characterised and the results suggested distinct pockets of different serotypes. Growth curves for L. monocytogenes isolates suggest considerably reduced shelf-life for a variety of foods. For example, lettuce should not be stored at room temperature or the shelf-life is reduced from 6.5 days (chilled storage) to 3.3 days.The predicted shelf-life for fresh milk was 4.5 days (chilled storage). Chlorine (sodium hypochlorite, 5 ppm), 1-monolauroyl-rac-glycerol and a laurate ester (ester-glucoside laurate) were also tested for application as vegetable decontaminating agents in restaurant kitchens. The report concludes with recommendations for improved food safety and hygiene in Irish restaurants.
    • Irish Domestic Food Safety Knowledge, Practice and Microbiology with Particular Emphasis on Staphylococcus aureus

      Bolton, Declan J.; Kennedy, Jean; Cowan, Cathal (Teagasc, 01/06/2005)
      This study examined consumer food safety knowledge on the island of Ireland. Domestic refrigerators were tested for the presence of a range of pathogenic bacteria. The effect of refrigerated storage on the antibiotic resistance and thermal resistance of S . aureus were also investigated. Irish consumers displayed a considerable lack of knowledge about correct refrigeration temperatures and proper hygiene procedures to prevent crosscontamination in the kitchen. Domestic refrigerators were contaminated with a range of bacterial pathogens including S . aureus (41%), S almonella spp. (7%), E scherichia. coli (6%), L isteria monocytogenes (6%) and Y ersinia enterocolitica (2%).
    • Tracking of Salmonella through the Pork Slaughter Process

      Prendergast, Deirdre M.; Duggan, Sharon J.; Duffy, Geraldine; Downey, Gerard (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.
    • Control of Blown Pack Spoilage in Vacuum Packaged Meat

      Bolton, Declan J.; Moschonas, Galatios; Sheridan, James J.; Downey, Gerard (Teagasc, 01/10/2009)
      Blown pack spoilage (BPS) represents a significant commercial loss to Irish meat processors. This research discovered that the organisms causing BPS are ubiquitous in the abattoir environment, making eradication very difficult. The risk of BPS is best managed through a process of regular treatment of plant and equipment with a sporicidal agent such as peroxyacetic acid, good hygiene to minimise carcass contamination and removal of the heat shrinkage stage during vacuum packaging as this activates the spores and reduces the time to spoilage.
    • Antimicrobial antagonists against food pathogens; a bacteriocin perspective

      O'Connor, Paula M.; Ross, R Paul; Hill, Colin; Cotter, Paul D.; Science Foundation Ireland; 12/RC/2273 (Elsevier, 03/02/2015)
      Efforts are continuing to find novel bacteriocins with enhanced specificity and potency. Traditional plating techniques are still being used for bacteriocin screening studies, however, the availability of ever more bacterial genome sequences and the use of in silico gene mining tools have revealed novel bacteriocin gene clusters that would otherwise have been overlooked. Furthermore, synthetic biology and bioengineering-based approaches are allowing scientists to harness existing and novel bacteriocin gene clusters through expression in different hosts and by enhancing functionalities. The same principles apply to bacteriocin producing probiotic cultures and their application to control pathogens in the gut. We can expect that the recent developments on bacteriocins from Lactic Acid Bacteria (LAB) described here will contribute greatly to increased commercialisation of bacteriocins in food systems.
    • A case of bovine raw milk contamination with Listeria monocytogenes

      Hunt, Karen; Drummond, Niall; Murphy, Mary; Butler, Francis; Buckley, Jim; Jordan, Kieran; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine, Ireland; European Union (Biomed Central, 06/07/2012)
      During routine sampling of bulk raw milk on a dairy farm, the pathogenic bacteria Listeria monocytogenes was found to be a contaminant, at numbers < 100 cfu/ml. A strain with an indistinguishable pulsed-field gel electrophoresis pattern was isolated from the bulk milk two months later. Environmental swabs taken at the dairy environment were negative for the presence of L. monocytogenes, indicating a possible case of excretion of the L. monocytogenes directly into the milk. Milk samples were collected from the individual cows and analysed, resulting in the identification of L. monocytogenes excretion (at 280 cfu/ml) from one of the 4 mammary quarters of one dairy cow out of 180. When the infected cow was isolated from the herd, no L. monocytogenes was detected from the remaining herd. The pulsed-field gel electrophoresis pattern of the strain from the individual cow was indistinguishable from that originally isolated from the bulk milk. The infected cow did not show any clinical signs of disease, nor did the appearance of the milk have any physical abnormalities. Antibiotic treatment of the infected mammary quarter was found to be ineffective. This study shows that there can be risks associated with direct contamination of raw milk with L. monocytogenes.
    • Production of multiple bacteriocins from a single locus by gastrointestinal strains of Lactobacillus salivarius

      O'Shea, Eileen F.; O'Connor, Paula M.; Raftis, Emma J.; O'Toole, Paul W.; Stanton, Catherine; Cotter, Paul D.; Ross, R Paul; Hill, Colin (American Society for Microbiology, 07/10/2011)
      Bacteriocins produced by Lactobacillus salivarius isolates derived from gastrointestinal origin have previously demonstrated efficacy for in vivo protection against Listeria monocytogenes infection. In this study, comparative genomic analysis was employed to investigate the intraspecies diversity of seven L. salivarius isolates of human and porcine intestinal origin, based on the genome of the well characterised bacteriocin-producing strain L. salivarius UCC118. This revealed a highly conserved megaplasmid-encoded gene cluster in these strains involved in the regulation and secretion of two-component class IIb bacteriocins. However, considerable intraspecific variation was observed in the structural genes encoding the bacteriocin peptides. These ranged from close relatives of abp118 such as salivaricin P, which differs by 2 amino acids, to completely novel bacteriocins such as salivaricin T, which is characterized in this study. Salivaricin T inhibits closely related lactobacilli and bears little homology to previously characterized salivaricins. Interestingly, the two peptides responsible for salivaricin T activity, SalTα and SalTβ, share considerable identity with the component peptides of thermophilin 13, a bacteriocin produced by Streptococcus thermophilus. Furthermore, the salivaricin locus of strain DPC6488 also encodes an additional novel one-component class IId anti-listerial bacteriocin, salivaricin L. These findings suggest a high level of redundancy in the bacteriocins that can be produced by intestinal L. salivarius isolates using the same enzymatic production and export machinery. Such diversity may contribute to their ability to dominate and compete within the complex microbiota of the mammalian gut.
    • Determination of Listeria monocytogenes numbers at less than 10 cfu/g

      Hunt, K.; Vacelet, M.; Jordan, Kieran; Department of Agriculture, Food and the Marine, Ireland; Dairy Processing Technology Centre; 11/F/008; TC 2014 0016. (Teagasc (Agriculture and Food Development Authority), Ireland, 09/06/2017)
      Listeria monocytogenes is a foodborne pathogen that causes a relatively rare foodborne disease called listeriosis, with a high mortality rate of 20%-30% and an undefined dose response. Current European Union regulations permit up to 100 colony-forming units (cfu)/g in food at the end of its shelf life, where the food has been shown not to support the growth of this pathogenic bacterium. Therefore, enumeration of L. monocytogenes at low numbers in food is important. The objective of this study was to reduce the detection limit of L. monocytogenes in food by a factor of 10. The International Organisation for Standardisation (ISO) 11290-2 method for enumeration of L. monocytogenes in food recommends spreading 0.1 mL of a 1:10 dilution of the food on the surface of an agar plate (detection limit 100 cfu/g), or 1.0 mL spread in equal parts on the surface of three agar plates (detection limit: 10 cfu/g). The pour-plate method (using 1 or 10 mL of an appropriate dilution) was compared to the spread-plate method using the ISO-approved chromogenic medium Agar Listeria according to Ottaviani and Agosti (ALOA). Using the pour-plate method, the colony morphology and halo formation were similar to the spread-plate method from pure cultures and inoculated foods. Using the pour-plate method in a 140 mm Petri dish, 10 mL of a 1:10 dilution of food allowed determination of numbers as low as 1 cfu/g. Applying this method, L. monocytogenes in naturally contaminated food samples were enumerated at numbers as low as 1-9 cfu/g.
    • Determining the Prevalence and Seasonality of Fasciola hepatica in Pasture-based Dairy herds in Ireland using a Bulk Tank Milk ELISA

      Bloemhoff, Yris; Forbes, Andrew; Danaher, Martin; Good, Barbara; Morgan, Eric; Mulcahy, Grace; Sekiya, Mary; Sayers, Riona (Biomed Central, 09/07/2015)
      Background Fasciola hepatica is a helminth parasite of global importance in livestock, with major economic impact. However information on F. hepatica infections in Irish pasture-based dairy herds is limited. Therefore this study was conducted in order to determine the prevalence, seasonality and management factors associated with F. hepatica. A total of 319 Irish dairy herds were selected for this study. Bulk tank milk (BTM) samples were collected from 290 dairy farms on a quarter year basis, while from a further 29 dairy farms BTM samples were collected on a monthly basis to provide a more detailed pattern of F. hepatica exposure in Irish herds. BTM samples were analysed using a commercially available F. hepatica antibody detection ELISA. Furthermore, within-herd prevalence of F. hepatica was assessed in a subset of these 29 herds (n = 17); both individual serum samples and bulk tank milk samples were collected. Results A within-herd prevalence of ≤ 50 % was found for herds with negative bulk tank milk samples. The mean prevalence of the 290 study herds was 75.4 % (Range 52 %–75.1 %), with the highest prevalence being observed in November (75.1 %). The seasonal pattern of F. hepatica shows elevated antibodies as the grazing season progressed, reaching a peak in January. A significant association was found between F. hepatica and age at first calving. Conclusion This study demonstrates that F. hepatica is present in a large proportion of Irish dairy herds and provides a basis on which control practices, particularly in adult dairy cows, can be reviewed.
    • Current trends in sample preparation for growth promoter and veterinary drug residue analysis

      Kinsella, Brian; O'Mahony, John; Malone, Edward; Moloney, Mary; Cantwell, Helen; Furey, Ambrose; Danaher, Martin (Elsevier, 09/09/2009)
      A comprehensive review is presented on the current trends in sample preparation for isolation of veterinary drugs and growth promotors from foods. The objective of the review is to firstly give an overview of the sample preparation techniques that are applied in field. The review will focus on new techniques and technologies, which improve efficiency and coverage of residues. The underlying theme to the paper is the developments that have been made in multi-residue methods and particularly multi-class methods for residues of licensed animal health products, which have been developed in the last couple of years. The role of multi-class methods is discussed and how they can be accommodated in future residue surveillance.
    • Determination and Occurrence of Phenoxyacetic Acid Herbicides and Their Transformation Products in Groundwater Using Ultra High Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry

      McManus, Sarah-Louise; Moloney, Mary; Richards, Karl G.; Coxon, Catherine E.; Danaher, Martin; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine, Ireland (MDPI AG., Basel, Switzerland, 10/12/2014)
      A sensitive method was developed and validated for ten phenoxyacetic acid herbicides, six of their main transformation products (TPs) and two benzonitrile TPs in groundwater. The parent compounds mecoprop, mecoprop-p, 2,4-D, dicamba, MCPA, triclopyr, fluroxypr, bromoxynil, bentazone, and 2,3,6-trichlorobenzoic acid (TBA) are included and a selection of their main TPs: phenoxyacetic acid (PAC), 2,4,5-trichloro-phenol (TCP), 4-chloro-2-methylphenol (4C2MP), 2,4-dichlorophenol (DCP), 3,5,6-trichloro-2-pyridinol (T2P), and 3,5-dibromo-4-hydroxybenzoic acid (BrAC), as well as the dichlobenil TPs 2,6-dichlorobenzamide (BAM) and 3,5-dichlorobenzoic acid (DBA) which have never before been determined in Irish groundwater. Water samples were analysed using an efficient ultra-high performance liquid chromatography (UHPLC) method in an 11.9 min separation time prior to detection by tandem mass spectrometry (MS/MS). The limit of detection (LOD) of the method ranged between 0.00008 and 0.0047 µg·L−1 for the 18 analytes. All compounds could be detected below the permitted limits of 0.1 µg·L−1 allowed in the European Union (EU) drinking water legislation [1]. The method was validated according to EU protocols laid out in SANCO/10232/2006 with recoveries ranging between 71% and 118% at the spiked concentration level of 0.06 µg·L−1. The method was successfully applied to 42 groundwater samples collected across several locations in Ireland in March 2012 to reveal that the TPs PAC and 4C2MP were detected just as often as their parent active ingredients (a.i.) in groundwater.
    • Controlling Blown Pack Spoilage Using Anti-Microbial Packaging

      Reid, Rachael; Bolton, Declan; Tiuftin, Andrey; Kerry, Joe P.; Fanning, Seamus; Whyte, Paul (MDPI, 12/08/2017)
      Active (anti-microbial) packaging was prepared using three different formulations; Auranta FV; Inbac-MDA and sodium octanoate at two concentrations (2.5 and 3.5 times their minimum inhibitory concentration (MIC, the lowest concentration that will inhibit the visible growth of the organisms) against Clostridium estertheticum, DSMZ 8809). Inoculated beef samples were packaged using the active packaging and monitored for 100 days storage at 2 °C for blown pack spoilage. The time to the onset of blown pack spoilage was significantly (p < 0.01) increased using Auranta FV and sodium octanoate (caprylic acid sodium salt) at both concentrations. Moreover, sodium octanoate packs had significantly (p < 0.01) delayed blown pack spoilage as compared to Auranta FV. It was therefore concluded that Auranta FV or sodium octanoate, incorporated into the packaging materials used for vacuum packaged beef, would inhibit blown pack spoilage and in the case of the latter, well beyond the 42 days storage period currently required for beef primals
    • Detection of benzimidazole carbamates and amino metabolites in liver by surface plasmon resonance-biosensor

      Keegan, Jemma; O'Kennedy, Richard; Crooks, Steven; Elliot, Christopher; Brandon, David; Danaher, Martin (Elsevier, 14/01/2011)
      Two surface plasmon resonance (SPR) biosensor screening assays were developed and validated to detect 11 benzimidazole carbamate (BZT) and four amino-benzimidazole veterinary drug residues in liver tissue. The assays used polyclonal antibodies, raised in sheep, to detect BZTs and amino-benzimidazoles. A modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction method was developed to isolate benzimidazole carbamate residues. Liver samples were extracted using an acetonitrile extraction method. BZTs were purified by dispersive solid phase extraction (d-SPE) using C18 sorbent. Residues of amino-benzimidazoles were effectively cleaned-up using a simple cyclohexane defatting step. The assays were validated in accordance with the performance criteria described in 2002/657/EC. The BZT assay limit of detection was calculated to be 32 μg kg−1, the detection capability (CCβ) was determined to be 50 μg kg−1 and the mean recovery of analytes was in the range 77–132%. The amino-benzimidazole assay limit of detection was determined to be 41 μg kg−1, the CCβ was determined to be 75 μg kg−1 and analyte recovery was in the range 103–116%. Biosensor assay performance was tested by analysing liver tissue from animals treated with benzimidazole drugs and comparing the results with an ultra high performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) confirmatory method. All non-compliant samples were identified using the biosensor assays.
    • The effect of antimicrobials on verocytotoxin bacteriophage transduction under bovine rumen fluid and broth conditions

      Nyambe, Sepa; Burgess, Catherine; Whyte, P.; Bolton, Declan; Department of Agriculture, Food and the Marine, Ireland; 11/F/051 (Teagasc (Agriculture and Food Development Authority), Ireland, 15/11/2017)
      The verocytotoxin genes in verocytotoxigenic Escherichia coli (VTEC) are carried by bacteriophages, incorporated into the bacterial genome (prophage). Antibiotics may promote phage replication and release to infect other cells (transduction), thus leading to the emergence of new VTEC strains. This study investigated transduction of a verocytotoxin2-encoding bacteriophage (3538(vtx2::cat)) under laboratory conditions, including the effect of antibiotic treatments. Luria-Bertani Miller broth and rumen fluid (raw and sterilised by irradiation) were inoculated with the donor (C600φ3538(Δvtx2::cat)) and recipient (E. coli C600::kanamycinR) strains (4 log10 cfu/mL) and incubated at 38°C. Antibiotic treatments (minimal inhibitory and sub-inhibitory concentrations of ampicillin, cefquinome, oxytetracycline and sodium sulfamethazine) were applied after 3 h. Samples were tested for donor, recipient, cell-free phage and transductants at times t = 0, 3, 4, 6, 27 (24 h post-antibiotic treatment) and 51 h. Free phage was detected in the untreated broth and rumen samples, as were the transductants confirmed by polymerase chain reaction. The antibiotic treatments did not significantly (P > 0.01) increase the concentrations of free phage or transductants detected. It was therefore concluded that, under laboratory conditions, the antibiotics tested did not induce bacteriophage lysis, release and infection of new bacterial cells beyond that constitutively found in the phage population.
    • Production of bioactive substances by intestinal bacteria as a basis for explaining probiotic mechanisms: Bacteriocins and conjugated linoleic acid

      O'Shea, Eileen F.; Cotter, Paul D.; Stanton, Catherine; Ross, R Paul; Hill, Colin (Elsevier Science B.V., 16/01/2012)
      The mechanisms by which intestinal bacteria achieve their associated health benefits can be complex and multifaceted. In this respect, the diverse microbial composition of the human gastrointestinal tract (GIT) provides an almost unlimited potential source of bioactive substances (pharmabiotics) which can directly or indirectly affect human health. Bacteriocins and fatty acids are just two examples of pharmabiotic substances which may contribute to probiotic functionality within the mammalian GIT. Bacteriocin production is believed to confer producing strains with a competitive advantage within complex microbial environments as a consequence of their associated antimicrobial activity. This has the potential to enable the establishment and prevalence of producing strains as well as directly inhibiting pathogens within the GIT. Consequently, these antimicrobial peptides and the associated intestinal producing strains may be exploited to beneficially influence microbial populations. Intestinal bacteria are also known to produce a diverse array of health-promoting fatty acids. Indeed, certain strains of intestinal bifidobacteria have been shown to produce conjugated linoleic acid (CLA), a fatty acid which has been associated with a variety of systemic health-promoting effects. Recently, the ability to modulate the fatty acid composition of the liver and adipose tissue of the host upon oral administration of CLA-producing bifidobacteria and lactobacilli was demonstrated in a murine model. Importantly, this implies a potential therapeutic role for probiotics in the treatment of certain metabolic and immunoinflammatory disorders. Such examples serve to highlight the potential contribution of pharmabiotic production to probiotic functionality in relation to human health maintenance.
    • Residue analyses and exposure assessment of the Irish population to nitrofuran metabolites from different food commodities in 2009–2010

      Radovnikovic, Anita; Conroy, Emma-Rose; Gibney, Mike; O'Mahoney, John; Danaher, Martin (Taylor & Francis, 16/09/2013)
      An exposure assessment to nitrofuran residues was performed for three human populations (adults, teenagers and children), based on residue analyses of foods of animal origin (liver, honey, eggs and aquaculture) covering the 2-year period 2009– 2010. The occurrence of nitrofuran metabolites in food on the Irish market was determined for the selected period using the data from Ireland’s National Food Residue Database (NFRD) and from results obtained from the analysis of retail samples (aquaculture and honey). Laboratory analyses of residues were performed by methods validated in accordance with Commission Decision 2002/657/EC regarding performance of the analytical method and interpretation of results. Semicarbazide (SEM) was the contaminant most frequently identified and its content ranged from 0.09 to 1.27 μg kg−1. SEM is currently used as a marker of nitrofuran abuse, but it may also occur from other sources. The presence of nitrofuran metabolite 3-amino-2-oxazolidinone (AOZ) was detected in two aquaculture samples (prawns) at 1.63 and 1.14 μg kg−1, but such a low number of positive cases did not present sufficient data for a full AOZ exposure assessment. Therefore, the evaluation of exposure was focused on SEM-containing food groups only. Exposure assessments were completed using a probabilistic approach that generated 10 iterations. The results of both the upper- and lower-bound exposure assessments demonstrate that SEM exposure for Irish adults, teenagers and children from selected food commodities are well below EFSA-estimated safe levels.
    • Control and detection of food-borne pathogens

      Duffy, Geraldine; Cloak, Orla; Sheridan, James J. (Teagasc, Ballsbridge, Dublin 4, 1998-08)
      The objective of this study was to develop rapid methods for the detection of bacteria from food.
    • The microbiological safety and quality of foods processed by the "sous vide" system as a method of commercial catering

      Bolton, Declan J. (Teagasc, Ballsbridge, Dublin 4, 1998-08)
      The objective of this project was to improve the quality and safety of sous vide foods by investigating the responses of the food-poisoning microorganisms to the processing and storage conditions used in this technology. The major food poisoning bacteria of concern in sous vide foods are strains of Clostridium botulinum, Bacillus cereus, verotoxigenic Escherichia coli O157:H7 (VTEC), Salmonella spp., Listeria monocytogenes and Yersinia enterocolitica.
    • Escherichia coli 0157:H7: implications for HACCP on the farm and in the abattoir

      Bolton, Declan J.; Byrne, Catriona; Sheridan, James J.; Riordan, Denise C. (Teagasc, 1999-01)
      Experiments were designed to assess the risks associated with Escherichia coli O157:H7 on the farm, through the abattoir and into the butcher shop. Data was also generated for application in model building and the reliability of pathogen models for predicting pathogen growth in different foods was examined.