• 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.
    • Assessment of the Effectiveness of Pre-harvest Meat Safety Interventions to Control Foodborne Pathogens in Broilers: a Systematic Review

      Pessoa, Joana; Rodrigues da Costa, Maria; Nesbakken, Truls; Meemken, Diana; European Union (Springer Science and Business Media LLC, 2021-02-14)
      Purpose of Review Ensuring broilers’ meat safety is a priority to policy makers, producers, and consumers. This systematic review aims to update the recent knowledge on pre-harvest interventions to control main foodborne pathogens in broilers and to assess their effectiveness. Recent Findings A total of 815 studies were retrieved from PubMed® andWeb of Science for 13 pathogens. In total, 51 studies regarding Campylobacter spp., Salmonella spp., VTEC, ESBL-AmpC Escherichia coli, and Clostridium perfringens were included in this review. Summary Research mostly focused on Salmonella spp. and Campylobacter spp. Biosecurity and management interventions had mixed outcomes, while the effectiveness of feed additives, though intensively researched, remains controversial. Research on other pathogens (i.e. ESBL-AmpC E. coli/Salmonella, and Toxoplasma gondii) was scarce, with publications focusing on epidemiology and/or on source-attribution studies. This is also true regarding research on Listeria monocytogenes, Bacillus cereus, Clostridium botulinum, Clostridium perfringens, and Staphylococcus aureus as these are frequently controlled by post-harvest interventions. Overall, studies on recent developments of novel pathogen-specific immunisation strategies are lacking.
    • 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).
    • Comparative analysis of Salmonella susceptibility and tolerance to the biocide chlorhexidine identifies a complex cellular defense network

      Condell, Orla; Power, Karen A.; Handler, Kristian; Finn, Sarah; Sheridan, Aine; Sergeant, Kjell; Renaut, Jenny; Burgess, Catherine; Hinton, Jay C.D.; Nally, Jarlath E.; et al. (Frontiers Media SA, 2014-08-01)
      Chlorhexidine is one of the most widely used biocides in health and agricultural settings as well as in the modern food industry. It is a cationic biocide of the biguanide class. Details of its mechanism of action are largely unknown. The frequent use of chlorhexidine has been questioned recently, amidst concerns that an overuse of this compound may select for bacteria displaying an altered susceptibility to antimicrobials, including clinically important anti-bacterial agents. We generated a Salmonella enterica serovar Typhimurium isolate (ST24CHX) that exhibited a high-level tolerant phenotype to chlorhexidine, following several rounds of in vitro selection, using sub-lethal concentrations of the biocide. This mutant showed altered suceptibility to a panel of clinically important antimicrobial compounds. Here we describe a genomic, transcriptomic, proteomic, and phenotypic analysis of the chlorhexidine tolerant S. Typhimurium compared with its isogenic sensitive progenitor. Results from this study describe a chlorhexidine defense network that functions in both the reference chlorhexidine sensitive isolate and the tolerant mutant. The defense network involved multiple cell targets including those associated with the synthesis and modification of the cell wall, the SOS response, virulence, and a shift in cellular metabolism toward anoxic pathways, some of which were regulated by CreB and Fur. In addition, results indicated that chlorhexidine tolerance was associated with more extensive modifications of the same cellular processes involved in this proposed network, as well as a divergent defense response involving the up-regulation of additional targets such as the flagellar apparatus and an altered cellular phosphate metabolism. These data show that sub-lethal concentrations of chlorhexidine induce distinct changes in exposed Salmonella, and our findings provide insights into the mechanisms of action and tolerance to this biocidal agent.
    • 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.
    • Determination of the presence of pathogens and anthelmintic drugs in raw milk and raw milk cheeses from small scale producers in Ireland

      Lourenco, Antonio; Fraga-Corral, Maria; De Colli, Lorenzo; Moloney, Mary; Danaher, Martin; Jordan, Kieran; Depart of Agriculture, Food and the Marine; 15/F/690 (Elsevier, 2020-04-03)
      This aim of this study was to assess the microbiological and anthelmintic drug residue risks associated with raw milk used for cheesemaking and raw milk cheese, over an 18-month period. Samples of raw milk, milk filters, curd and cheese from nine raw milk artisan cheese producers in the south of Ireland were tested. Numbers of presumptive Bacillus cereus group, Escherichia coli, Salmonella spp., Staphylococcus aureus and Listeria monocytogenes were determined. The determination of anthelmintic drug residues, including benzimidazoles, flukicides, macrocyclic lactone (avermectin and milbemycins), levamisole and morantel was also performed. Neither L. monocytogenes, nor Salmonella spp. were detected in any of the samples tested and no anthelmintic drug residues were detected. Only one of the samples did not conform with regulatory numbers for other bacteria. This survey has shown a good microbiological and residue quality (and low risk) of the raw milk cheese and raw milk used for raw milk cheese produced in Ireland. Moreover, it has shown the importance of frequent assessment of raw milk used for cheesemaking and for raw milk cheese, as it allows the identification of potential problems facilitating resolution of these issues before they cause any public health threat.
    • Early Salmonella Typhimurium infection in pigs disrupts Microbiome composition and functionality principally at the ileum mucosa

      Argüello, Héctor; Estellé, Jordi; Zaldívar-López, Sara; Jiménez-Marín, Ángeles; Carvajal, Ana; López-Bascón, Mª Asunción; Crispie, Fiona; O’Sullivan, Orla; Cotter, Paul D.; Priego-Capote, Feliciano; et al. (Springer Nature, 2018-05-17)
      Salmonella is a major foodborne pathogen which successfully infects animal species for human consumption such as swine. The pathogen has a battery of virulence factors which it uses to colonise and persist within the host. The host microbiota may play a role in resistance to, and may also be indirectly responsible from some of the consequences of, Salmonella infection. To investigate this, we used 16S rRNA metagenomic sequencing to determine the changes in the gut microbiota of pigs in response to infection by Salmonella Typhimurium at three locations: ileum mucosa, ileum content and faeces. Early infection (2 days post-infection) impacted on the microbiome diversity at the mucosa, reflected in a decrease in representatives of the generally regarded as desirable genera (i.e., Bifidobacterium and Lactobacillus). Severe damage in the epithelium of the ileum mucosa correlated with an increase in synergistic (with respect to Salmonella infection; Akkermansia) or opportunistically pathogenic bacteria (Citrobacter) and a depletion in anaerobic bacteria (Clostridium spp., Ruminococcus, or Dialliser). Predictive functional analysis, together with metabolomic analysis revealed changes in glucose and lipid metabolism in infected pigs. The observed changes in commensal healthy microbiota, including the growth of synergistic or potentially pathogenic bacteria and depletion of beneficial or competing bacteria, could contribute to the pathogen’s ability to colonize the gut successfully. The findings from this study could be used to form the basis for further research aimed at creating intervention strategies to mitigate the effects of Salmonella infection.
    • Hygiene and safety of Irish beef carcasses.

      Kerr, Marie; Sheridan, James J. (Teagasc, 2002-10)
      Investigations were carried out in a number of beef abattoirs in Ireland. Information was obtained on the hygienic status of the carcasses being produced and also on their safety, using the presence of Salmonella as an indicator. The data showed that, in general, the hygiene of the carcasses being produced was of a satisfactory quality and that faecal contamination was low, as indicated by the coliform and E. coli counts. The safety of the carcasses as indicated by the presence of Salmonella was considered to be a cause for concern. The level of contamination by this pathogen of 7.6% was considered to be high and requires investigation. The majority of the Salmonella present on carcasses was S. typhimurium DT104, which is resistant to a range of antibodies. The work was part of an EU project and some results are presented from other partners.
    • Irish domestic food safety knowledge, practice and microbiology with particular emphasis on staphylococcus aureus

      Bolton, Declan; Kennedy, Jean; Cowan, Cathal (Teagasc, 2005-06)
      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%). Viewing Options
    • A preliminary study of Salmonella spp., Listeria monocytogenes, Escherichia coli O157, Enterococcus faecalis and Clostridium spp. in Irish cattle

      Russell, L.; Galindo, C.P.; Whyte, P.; Bolton, Declan; Department of Agriculture, Food and the Marine; Teagasc Walsh Scholarship Programme; 14/SF/487; 2014239 (Teagasc, 2021-06-03)
      Although Salmonella spp., Escherichia coli O157, Listeria monocytogenes, Enterococcus faecalis and Clostridium spp. present a significant food safety and/or spoilage issue for the beef sector, there are limited data on their prevalence in Irish cattle. The objectives of this preliminary study were to investigate the distribution (percentage of farms positive) of Salmonella spp., E. coli O157, L. monocytogenes, E. faecalis and Clostridium spp. and the overall prevalence (%) of these bacteria in cattle on a small cohort of Irish beef farms. A total of 121 fresh bovine faecal samples were obtained on 10 randomly selected beef farms in the Northeast of Ireland and tested for the target pathogens using standard culture-based methods. Presumptive positives were confirmed using previously published polymerase chain reaction (PCR) methods. Salmonella were not detected in any of the samples. E. coli O157, L. monocytogenes, E. faecalis and Clostridium spp. were present on 50%, 40%, 100% and 100% of farms, respectively, with overall (all farms) prevalence rates in cattle of 9%, 8.2%, 61.9% and 87.6%, respectively. This study suggests that E. coli O157 may be more prevalent than previously thought and L. monocytogenes, E. faecalis and Clostridium spp. are widespread in Irish beef animals.
    • The response of foodborne pathogens to osmotic and desiccation stresses in the food chain

      Burgess, Catherine; Gianotti, Andrea; Gruzdev, Nadia; Holah, John; Knøchel, Susanne; Lehner, Angelika; Margas, Edyta; Esser, Stephan Schmitz; Sela (Saldinger), Shlomo; Tresse, Odile; et al. (Elsevier BV, 2016-01-02)
      In combination with other strategies, hyperosmolarity and desiccation are frequently used by the food processing industry as a means to prevent bacterial proliferation, and particularly that of foodborne pathogens, in food products. However, it is increasingly observed that bacteria, including human pathogens, encode mechanisms to survive and withstand these stresses. This review provides an overview of the mechanisms employed by Salmonella spp., Shiga toxin producing E. coli, Cronobacter spp., Listeria monocytogenes and Campylobacter spp. to tolerate osmotic and desiccation stresses and identifies gaps in knowledge which need to be addressed to ensure the safety of low water activity and desiccated food products.
    • The response of foodborne pathogens to osmotic and desiccation stresses in the food chain

      Burgess, Catherine; Gianotti, Andrea; Gruzdev, Nadia; Holah, John; Knøchel, Susanne; Lehner, Angelika; Margas, Edyta; Schmitz Esser, Stephan; Sela (Saldinger), Shlomo; Tresse, Odile; et al. (Elsevier, 2016-01-02)
      In combination with other strategies, hyperosmolarity and desiccation are frequently used by the food processing industry as a means to prevent bacterial proliferation, and particularly that of foodborne pathogens, in food products. However, it is increasingly observed that bacteria, including human pathogens, encode mechanisms to survive and withstand these stresses. This review provides an overview of the mechanisms employed by Salmonella spp., Shiga toxin producing E. coli, Cronobacter spp., Listeria monocytogenes and Campylobacter spp. to tolerate osmotic and desiccation stresses and identifies gaps in knowledge which need to be addressed to ensure the safety of low water activity and desiccated food products.
    • The response of foodborne pathogens to osmotic and desiccation stresses in the food chain

      Burgess, Catherine; Gianotti, Andrea; Gruzdev, Nadia; Holah, John; Knøchel, Susanne; Lehner, Angelika; Margas, Edyta; Esser, Stephan Schmitz; Sela (Saldinger), Shlomo; Tresse, Odile; et al. (Elsevier BV, 2016-03)
      In combination with other strategies, hyperosmolarity and desiccation are frequently used by the food processing industry as a means to prevent bacterial proliferation, and particularly that of foodborne pathogens, in food products. However, it is increasingly observed that bacteria, including human pathogens, encode mechanisms to survive and withstand these stresses. This review provides an overview of the mechanisms employed by Salmonella spp., Shiga toxin producing E. coli, Cronobacter spp., Listeria monocytogenes and Campylobacter spp. to tolerate osmotic and desiccation stresses and identifies gaps in knowledge which need to be addressed to ensure the safety of low water activity and desiccated food products.
    • 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.
    • 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.