• The quality of under-utilised deep-water fish species

      Brennan, Martine H.; Gormley, Ronan T.; European Union; Marine Research Measure (Teagasc, 1999-09)
      The quality of twenty-three frozen under-utilised fish species was examined. The species were spot samples of deep-water fish caught near the Rockall Trough by the Fisheries Research Centre. Their basic composition was 80.8 - 86.4% water, 9.8 - 25.2% protein, 0.18 - 16.2% lipid and 0.7 - 2.0% ash. Lead, cadmium and mercury concentrations were determined for six species and were much lower than the maximum levels set in 1992. Ammonia levels were unacceptably high in three shark species.
    • 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.
    • Rapid control systems for veterinary drug residues in food producing animals

      O'Keeffe, Michael; European Union; SMT4 - CT96 - 2092 (Teagasc, 2002-10)
      The aim was to develop rapid systems which could be used to test for the presence of veterinary drug residues in food producing animals. Body fluid samples are most suitable for rapid testing systems so as to avoid the lengthy residue extraction procedures required for tissue samples. Urine was analysed for sulphamethazine, a licensed antimicrobial, and for chlorotestosterone, a prohibited growth promoting agent, as models to demonstrate the different approaches.
    • Rapid cooling of cooked meat joints

      Kenny, Tony; Desmond, Eoin; Ward, Patrick; Sun, Da-Wen (Teagasc, 2002-02)
      Conventional cooling by air-blast or even by immersion in liquid is unlikely to achieve recommended cooling rates when dealing with joints weighing 5kg or more because meat has a low thermal conductivity. The objective was to investigate vacuum cooling as a technique for rapid chilling of cooked meat joints. In vacuum cooling, the food is enclosed in a chamber and reduction of the pressure to about 7 mbar causes evaporation of water from the surface of the food and from cavities in the food. The energy required to evaporate the water is extracted from the food, resulting in rapid chilling
    • 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.
    • Reducing the incidence of boar taint in Irish pigs

      Allen, Paul; Joseph, Robin; Lynch, Brendan (Teagasc, 2001-04)
      Boar taint is an unpleasant odour that is released during cooking from some pork and products made from the meat and fat of non-castrated male pigs. Only a proportion of boars produce this odour and not all consumers are sensitive to it. Nevertheless it is a potential problem for the industry since an unpleasant experience can mean that a sensitive consumer may not purchase pork or pork products again. Some European countries are very concerned about this problem and most castrate all the male pigs not required for breeding. Irish pig producers ceased castration more than 20 years ago because boars are more efficient converters of feed into lean meat and a research study had shown that boar taint was not a problem at the carcass weights used in this country at that time.
    • Relating starch properties to boiled potato texture

      Gormley, Ronan T.; Department of Agriculture, Food and the Marine (Teagasc, Ballsbridge, Dublin 4, 1998-08)
      Basic information on starch properties may help to explain the different textural characteristics of potato cultivars, and also their suitability for different forms of processing. The study involved tests on both raw potatoes, and on starch separated from potatoes, and embraced three main activities: (i) to relate boiled-potato texture with the other test variables; (ii) to develop a rapid crush-test for assessing cooked-potato texture; (iii) to study the effect of chilling and freezing on the development of resistant starch (RS) in boiled potatoes.
    • A risk assessment and hazard analysis and critical control point (HACCP) study for the Irish catering industry

      Bolton, Declan J.; Meally, Aisling; Downey, Gerard; Safefood (Teagasc, 2007-02)
      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.
    • A Risk Assessment and Hazard Analysis and Critical Control Point (HACCP) Study for the Irish Catering Industry

      Bolton, Declan J.; Meally, Aisling; Downey, Gerard; Safefood (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.
    • Risk-based determination of critical control points for pork slaughter

      Bolton, Declan J.; Pearce, Rachel; Sheridan, James J.; Department of Agriculture, Food and the Marine, Ireland (Teagasc, 2002-05)
      To identify the critical control points (CCPs) during commercial pork slaughter, 60 pigs in a small abattoir (80 pigs per day) and a similar number in a larger plant (2000 pigs per day) and/or their resultant carcasses were swabbed at the ham, belly and neck. The total bacterial contamination was determined after each stage from the live pigs on the farm to chilling of the carcasses in the abattoir.
    • Role of Lactobacilli in Flavour Development of Cheddar Cheese.

      Beresford, Tom; Cogan, Tim; Rea, Mary C.; Drinan, Finbarr; Fitzsimons, Nora; Brennan, N.; Kenny, Owen; Fox, P.F. (Teagasc, 2001-05-01)
      Cheddar cheese is a complex microbial ecosystem. The internal cheese environment, in particular of hard and semi-hard cheeses, is not conducive to the growth of many microorganisms. At the beginning of ripening the dominant microorganisms are the starter bacteria which are present at high levels (~109/g). However, during ripening, non-starter lactic acid bacteria (NSLAB) grow from relatively low levels (<103/g) at the beginning of ripening, to 108/g within 6 - 8 weeks. Other bacteria, e.g. enterococci and staphylococci, may also be present but in much lower numbers. In a previous study of mature and extra mature Cheddar cheeses from different manufacturers (see End of Project Report No. 1), it was found that the NSLAB population was dominated by strains of Lb. paracasei. However, their contribution to cheese flavour and their source(s) are still unclear, nor is it known if the NSLAB flora is unique to each plant. Hence, understanding the growth of this group of organisms in cheese is a key to defining their role in flavour development. The biochemistry of flavour development in cheese is poorly understood. For most cheese varieties, including Cheddar, proteolysis, which results in the accumulation of free amino acids, is of vital importance for flavour development. Increasing evidence suggests that the main contribution of amino acids is as substrates for the development of more complex flavour and aroma compounds. The manner by which such compounds are generated in cheese is currently the focus of much research. Starter bacteria have been shown to contain a range of enzymes capable of facilitating the conversion of amino acids to potential flavour compounds. However, the potential of lactobacilli (NSLAB) to produce similar enzymes has only recently been investigated. Hence, although, it is generally accepted that the cheese starter flora is the primary defining influence on flavour development, the contribution of NSLAB is also considered significant. The objectives of these studies were: - to develop a greater understanding of the behaviour of NSLAB in cheese, and - to identify suitable strains, and other cheese bacteria, to be used as starter adjuncts for flavour improvement.
    • 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.
    • Second generation GM foods: perspectives on likely future acceptance by Irish consumers

      O'Connor, Elaine; Cowan, Cathal; Williams, Gwilym; O'Connell, John J.; Boland, Maurice; Downey, Gerard; Teagasc Walsh Fellowship Programme; Safefood; Safefood (Teagasc, 2005-07)
      Two hypothetical second-generation genetically-modified (GM) products, a yogurt and a dairy spread, were evaluated by consumers. Second-generation GM food products offer specific consumer benefits - in the case of this study, health benefits.
    • Second Generation GM Foods: Perspectives on Likely Future Acceptance by Irish Consumers

      O'Connor, Elaine; Cowan, Cathal; Williams, Gwilym; O'Connell, John J.; Boland, Maurice; Downey, Gerard (Teagasc, 01/07/2005)
      Two hypothetical second-generation genetically-modified (GM) products, a yogurt and a dairy spread, were evaluated by consumers. Second-generation GM food products offer specific consumer benefits - in the case of this study, health benefits.
    • Significance of Lactobacilli in Cheddar Cheese

      Cogan, Tim; Beresford, Tom; Drinan, Finbarr; Palles, Tony; Fitzsimons, Nora (Teagasc, 1998-09-01)
      The objectives of this project were to isolate and identify the non-starter lactobacilli in mature Cheddar cheese, identify strains which impart mature flavours to cheese and determine their role in developing cheese flavour. The main conclusions were as follows: Based on an analysis of 18 mature Cheddar cheeses, selected from 7 commercial manufacturers, non-starter lactic acid bacteria typically numbered, as expected, 106-108 per gram and were dominated (97 percent) by Lactobacillus paracasei. Although a small number of strains (typically 1 to 4) was found in each cheese there was considerable strain diversity in cheeses within as well as between manufacturing plants. When selected strains were investigated for survival and flavour enhancement when added (as starter adjuncts) with the normal starter cultures in Cheddar cheese manufacture, it was found that they remained dominant for up to 3 months of ripening. Commercial grading of these cheeses at 3 and 6 months confirmed that the added strains did modify flavour development and one (DPC 4103), in particular, had a beneficial effect. It was confirmed that two selected strains of non-starter lactobacilli were capable of metabolising citrate under the conditions of Cheddar cheese ripening and, consequently, if present in sufficient numbers, would influence flavour development. The work was greatly facilitated by the successful and novel adaptation of a modern rapid molecular technique (RAPD) for species and strain classification. In summary these studies found that one species of lactobacilli (Lb. paracasei) was the dominant non-starter lactic acid bacteria in mature Cheddar cheese. Although a wide variety of strains were identified, only a few were found in any particular cheese, suggesting their likely role in cheese flavour diversity even within the same manufacturing plant. This suggests the potential for flavour control or enhancement through the selective and controlled use of non-starter lactic acid bacteria. Preliminary investigations of the metabolism of those organisms supports this view and a follow-up study now in progress should provide greater clarity on this matter.
    • Spread of brain and spinal cord material during beef slaughter

      Daly, Dyan J.; Prendergast, Deirdre M.; Sheridan, James J. (Teagasc, 2002-04)
      Emboli of brain tissue in the lungs have been reported in cases following severe head injury (McMillan 1956) and birth trauma in people (Hauck e t al 1990) and in cattle following stunning (Bauer 1996; Garland 1996). This has important implications for food safety if the brain tissue of stunned cattle is infected with the prion responsible for bovine spongiform encephalopathy (BSE), (Prusiner 1991). BSE emerged following changes in the rendering process in the early 1980s which allowed the aetiologic agent to survive, contaminate protein feed supplement and infect cattle (Brown e t al. 2001). Within a short period of time after the first case of BSE, concerns were expressed regarding the transmission of BSE to humans and the likelihood of infection from consumption of beef and beef products. This has become increasingly significant with the discovery of the link between BSE in cattle and variant Creutzfeldt-Jakob disease (vCJD) in man (Bruce e t al 1997).
    • Status Report on Acrylamide in Potato Products

      Brunton, Nigel; Gormley, Ronan T.; Murray, Brendan (Teagasc, 2005-01-01)
      Acrylamide is a toxin that can potentially occur in high concentrations in heated starchy foods especially potato products such as crisps and french fries. In model systems isotopic substitution studies have demonstrated that acrylamide is formed via the Maillard type reaction between the amino acid aspargine and a carbonyl source such as the reducing sugars glucose and fructose. Levels of acrylamide in cooked potato products are primarily influenced by the levels of reducing sugars in the product and this in turn is influenced by storage time, temperature and variety of potato used. During cooking acrylamide formation begins to occur at temperatures above 100°C and increases up to temperatures of 220°C but decreases thereafter due to thermal degradation of the compound. Risk assessment studies on acrylamide intakes have been conducted in a number of countries and mg/kg body weight daily intakes have been estimated to be between 0.2-0.8. Adequate analytical techniques exist for quantification of acrylamide in potato and are mainly based around liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS) techniques
    • Stimulation of Propionic Acid Bacteria by Lactic Acid Bacteria in Cheese.

      Condon, S.; Cogan, Tim; Piveteau, P.; O'Callaghan, Jim; Lyons, B. (Teagasc, 2001-06-01)
      In the manufacture of Swiss-type cheese two successive fermentations occur. During manufacture, lactic acid bacteria (LAB), particularly Streptococcus thermophilus, Lactobacillus helveticus and Lb. delbrueckii subsp. lactis, convert lactose to lactate while, during ripening, propionic acid bacteria (PAB) convert lactate to propionic acid, acetic acid and carbon dioxide (CO2). CO2 is responsible for eye formation and propionic acid results in the typical nutty flavour of Swiss-type cheese. There have been a few reports of interactions between a small number of LAB and PAB but the compounds involved have not been identified. A better understanding of this phenomenon is necessary to select strains of PAB for cheesemaking and improve the quality of hard cheeses. Cheese cannot be used for such a study because of its complexity and the length of time it is ripened. Hence, a simple whey-based model developed by Piveteau et al (1995) was successfully used to study the interactions between LAB and PAB. In this procedure, the LAB were grown overnight in milk and the whey was collected by centrifugation. After neutralisation and filter-sterilisation, the growth of strains of PAB in this whey and in a control whey produced from the same milk by acidification with lactic acid were compared. The objectives of this study were to refine the model of Piveteau et al (1995) to study the interactions between LAB and PAB and to determine the nature of the stimulant(s) produced by the LAB. * Thirty-two combinations of different commercial strains of PAB and LAB were evaluated in a modified whey model. None showed any inhibition and all showed some degree of stimulation but the extent of the stimulation depended on the particular pair of PAB and LAB used. * An inhibitor of PAB was found in milk, which prevented the growth of PAB from low (105 cfu/ml) but not from high inocula (107 cfu/ml). The inhibitor was heat stable (to autoclaving for 15 min), of low molecular mass and could be removed by pre-growth of some but not all starter LAB in milk. * Growth of P. freudenreichii DPC 3801 in control whey was stimulated by peptone, tryptone, casein hydrolysed by the crude proteinase of Lb. helveticus DPC 4571 and by pre-growth of the lactobacillus in milk, but not by vitamins (riboflavin, thiamine, PABA, Ca panthothenate, biotin and nicotinic acid) or minerals (MgSO4, MnCl2, CoCl2 and CuSO4). * Growth of Lb. helveticus DPC 4571 in milk resulted in significant increases in peptide and amino acid production but the amino acids produced did not stimulate the growth of the PAB. Based on these results it was concluded that the stimulation was due to production of peptides by the LAB from casein. * The whey model developed by Piveteau et al (1995) to study the interactions between PAB and LAB was shown to be reproducible. Adjustment of the pH of the whey to 5.4 rather than 6.0, incubation at 24ºC rather than 30ºC and addition of 1% NaCl, to simulate cheese ripening conditions allowed growth of all the PAB tested. * Several chromatographic procedures, including ion-exchange, gel permeation and reverse-phase, high-pressure liquid chromatography failed to categorically identify the peptide(s) responsible for the stimulation of the PAB. In some of these chromatographic systems,the stimulatory activity was shown to be present in several peaks implying that different peptides were involved.
    • 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.
    • A study on the use of chilling as a critical control point in a beef HACCP plan

      Kinsella, Kathleen; Sheridan, James J.; Rowe, T.; Downey, Gerard; National Development Plan (NDP) (Teagasc, 01/02/2006)
      Investigations were undertaken to establish the critical limits for use of chilling in a Hazard Analysis Critical Control Point (HACCP) system for beef. Information was obtained on the influence of chilling on the survival of bacteria, including the pathogen Salmonella Typhimurium DT104, attached to beef carcass surfaces. In general, a chilling regime could not be identified that gave consistent and meaningful reductions in surface bacterial counts while not seriously compromising the quality of the carcasses in terms of excessive amounts of weight loss. The study concluded that chilling was not a satisfactory process for use as a critical control point (CCP) in beef chilling and could not be recommended to the Irish beef industry for inclusion in a HACCP plan.