• Food Authentication using Infrared Spectroscopic Methods

      Downey, Gerard; Kelly, J. Daniel (Teagasc, 01/06/2006)
      Confirmation of the authenticity of a food or food ingredient is an increasing challenge for food processors and regulatory authorities. This is especially the case when an added-value claim, such as one relating to geographic origin or a particular processing history, is made on the food label. Regulatory agencies are concerned with the prevention of economic fraud while the food processor needs confirmation of such claims in order to protect a brand, the image of which could be severely damaged should an adulterated ingredient make its way into the branded food product.To be of greatest value, any analytical tool deployed to confirm authenticity claims needs to be portable, easy to use, non-destructive and accurate. Infrared spectroscopy, near and mid-infrared, is a tool which has been demonstrated to possess these properties in a wide range of situations.While some applications in food authenticity have been reported, the work undertaken in this project was designed to explore their capabilities regarding a number of products and authenticity issues of particular interest to the Irish agri-food industry i.e. olive oil, honey, soft fruit purées and apple juice.
    • Food authentication using infrared spectroscopic methods

      Downey, Gerard; Kelly, J. Daniel (Teagasc, 2006-06)
      Confirmation of the authenticity of a food or food ingredient is an increasing challenge for food processors and regulatory authorities. This is especially the case when an added-value claim, such as one relating to geographic origin or a particular processing history, is made on the food label. Regulatory agencies are concerned with the prevention of economic fraud while the food processor needs confirmation of such claims in order to protect a brand, the image of which could be severely damaged should an adulterated ingredient make its way into the branded food product.
    • Food residue database

      O'Keeffe, Michael; Kennedy, Orla; Farrell, Frank; Nolan, Marie-Louise; Dooley, Martin; Byrne, Patrick; Nugent, Audrey; Cantwell, Helen; Horne, Elizabeth; Nelson, Victor; et al. (Teagasc, 2001-11)
      The Food Residue Database contains a broad range of residue studies in foods of animal origin for the period 1995 to 2000, covering veterinary drugs, pesticides and contaminants. In most cases, such as antiparasitic drugs, beta-agonists, pesticides, dioxins, mycotoxins, heavy metals and polycyclic aromatic hydrocarbons, the picture for Irish dairy, meat and fish products is good with residue levels being low or non-measurable. In a few cases, such as ivermectin in farmed salmon and tetracycline residues in pork, improvements in the situation were observed with subsequent studies. Antimicrobial residues, in general, are not a problem but levels above MRL values have been found indicating the need for good practice in use of veterinary medicines. A problem with elevated nitrate levels in dairy powders may be resolved by the industry through observance of good manufacturing practices. Summary Reports on all the studies carried out for the Food Residue Database are available to food companies and other interested parties.
    • Freeze-chilling and gas flushing of raw fish fillets

      Fagan, John; Gormley, Ronan T.; Uí Mhuircheartaigh, Mary M. (Teagasc, 2003-04)
      Freeze-chilling involves freezing and frozen storage followed by thawing and chilled storage. Trials with whiting and mackerel fillets/portions (Part 1) indicated no difference in odour scores (raw samples) between freeze-chilled and chilled samples; however, freeze-chilled salmon portions were inferior to chilled in terms of odour. Fresh fillets received the highest acceptability scores as cooked samples followed by frozen, chilled and freeze-chilled fillets. Freshness indicators were the same for the three species. Freeze-chilled fillets had the highest free fatty acid and peroxide values but the levels were low and did not influence sensory response. The effects of the four treatments on the colour and texture of the raw fillets were small in practical terms and typical shelf-lives in the chill phase of the freeze-chill process were 3 to 5 days. In Part 2, modified atmosphere packaging (MAP) was combined with freezechilling to further extend the shelf-life of raw whiting, mackerel and salmon fillets/portions. Typical shelf-lives in the chill phase for the freeze-chilled fillets were 5 (whiting and mackerel) and 7 (salmon) days. Good manufacturing practice coupled with HACCP and careful tempering (thawing) are essential for the successful freeze-chilling of raw fish fillets. Packs should be labelled ‘previously frozen’ for consumer information. It is concluded that freeze-chilling with MAP is a suitable technology for extending the shelf-life of raw fish fillets.
    • Freeze-chilling of ready-to-eat meal components

      Redmond, Grainne; Gormley, Ronan T.; Butler, Francis; Dempsey, Alan; Oxley, Eamon; Gerety, Ailis (Teagasc, 2004-03)
      Freeze-chilling of food consists of freezing and frozen storage followed by thawing and then retailing at chill storage temperatures. It offers logistic, transportation and storage advantages to food manufacturers. Freeze-chilling has particular application to ready-meals and their components. Mashed potato (three cultivars), steamed carrots, steamed green beans and beef lasagne were found suitable for freeze-chilling and their quality and sensory properties compared favourably with their frozen, chilled and fresh counterparts. Modified atmosphere packaging was combined with freeze-chilling but it had little impact on shelflife extension for the product range with the outcome similar to that for samples packed in air. Tests on the freeze-chilling of white sauces showed the importance of using freeze-thaw stable starches. Best-practice thawing procedures were established and the importance of stacking configurations for outer boxes (each with a number of lasagne ready-meals) was highlighted in the case of the commercial tempering unit. Trials on the re-freezing of freeze-chilled products indicated that re-freezing is an option provided the normal storage protocols for frozen and chilled foods are observed.
    • Functional Foods in Relation to Health and Disease (New Probiotic Cheddar Cheese).

      Stanton, Catherine; Ross, R Paul; Fitzgerald, Gerald F; Collins, K.; Gardiner, Gillian E. (Teagasc, 2000-09-01)
      Growing public awareness of diet-related health benefits has fuelled the demand for probiotic foods. These foods contain probiotic bacteria which are described as live microbial supplements that improve the intestinal microbial balance and are intended for maintenance of health and/or the prevention of disease. Probiotic bacteria for human use must be proven to be safe and beneficial, and should preferably be of human origin as evidence suggests that these bacteria are species specific and perform best in the species from which they were isolated. They must also retain both viability and efficacy in a particular food product throughout its shelf-life, and following consumption. Above all however, probiotic food products must be proved effective in controlled validated clinical trials. Dairy foods, including in particular, fermented milks and yogurt are among the best accepted food carriers for probiotic cultures. The aim of this study was to develop new probiotic foods, particularly, the production of high quality Cheddar cheese containing high levels of probiotic bacteria.
    • Functional ingredients as fat replacers in cakes and pastries

      Dwyer, Elizabeth; Gallagher, Eimear (Teagasc, 2001-05)
      For specific health concerns, consumers want fat taken out of food without the flavour and texture being adversely affected. Novel ingredients were investigated for use in the formulation of reduced fat bakery products. Formulations were developed for reduced fat muffins, madeira cake and shortcrust pastry by replacing some of the fat in the recipes with combinations of novel ingredients. The aim was to achieve at least a 25% fat reduction in the products while maintaining quality, texture, taste and consumer acceptability. Focus groups were used to ascertain consumers’ preferences for the reduced fat bakery products to determine which, if any, recipes had greatest potential for further development.
    • Genetic Variants of Milk Proteins - Relevance to Milk Composition and Cheese Production.

      Fitzgerald, Richard J.; Walsh, Daniel; Guinee, Timothy P.; Murphy, J.J.; Mehra, Raj; Harrington, D.; Connolly, J.F. (Teagasc, 1999-07-01)
      Objectives: (i) to develop rapid screening procedures for the determination of milk protein polymorphism (genetic variants) (ii) to determine the frequency distribution of milk protein genetic variants in a large population of Irish Holstein-Friesians and to determine if there was an association between κ-casein variant and milk yield and composition in this group of animals, and (iii) to make Cheddar and low-moisture part-skim Mozzarella cheese from different κ-casein genetic variant milks and to assess any effect on cheese yield, composition and functional characteristics. Conclusions:Analysis of 6,007 individual Irish Holstein-Friesian milks showed that the phenotype distribution of the κ-casein BB variant was very low at 1.98% compared to 53.07% for κ-casein AA and 44.95% for κ-casein AB. While no statistically significant associations were observed between κ-casein variant and milk yield and composition, κ-casein BB variant milks had superior rennet coagulation properties to that of the AA or AB variants. Generally, κ-casein variant had little effect on compositional attributes of cheese apart from FDM (fat in dry matter) which was significantly higher in cheeses from κ-casein BB milk than in those from κ-casein AA milk. Generally, κ-casein variant had no significant effects on either primary or secondary proteolysis, or on the sensory and/or textural characteristics of Cheddar or Mozzarella cheese throughout ripening; or on the functional characteristics (e.g. flow and stretch) of baked Mozzarella on storage for 90 days at 4°C. However, κ-casein BB variant milk gave significantly higher actual, and moisture adjusted yields of Cheddar and Mozzarella cheese than either κ-casein AB or AA variant milks. For example, the moisture adjusted Cheddar yield from κ-casein BB milk was 8.2% higher than from κ-casein AA milk. In the case of Mozzarella, the moisture adjusted yield was 12% higher. Based on the results, it is estimated that the actual yield of cheese in a plant producing 20,000 tonnes per year from κ-casein AA milk would increase to approximately 21,180 tonnes of Cheddar, or 21,780 tonnes of Mozzarella if made from κ-casein BB milk. Where κ-casein AB milk is used instead of κ-casein BB milk, the estimated yield of Mozzarella would increase to 21,580 tonnes.
    • HACCP for Irish beef, pork and lamb slaughter

      Bolton, Declan J.; Sheridan, James J.; US-Ireland Co-operation Programme in Agriculture Science and Technology; Department of Agriculture, Food and the Marine, Ireland (Teagasc, 2002-02)
      It is generally accepted that HACCP principles should be incorporated into the food safety control systems in meat processing plants to better assure food safety. The objective of this project was to publish detailed HACCP slaughter documents for the Irish beef, pork and lamb processing industries. These would provide the necessary information and detail to facilitate the implementation of HACCP on the slaughter floor (from lairage to chilling) in Irish meat plants. To this end `HACCP for Irish Beef Slaughter' was published in October 2000, `HACCP for Irish Pork Slaughter' in December 2001 and `HACCP for Irish Lamb Slaughter' will be available early in 2002. These are non-generic, detailed documents which provide the scientific basis for establishing critical control points (CCP), critical limits, monitoring and corrective action procedures.
    • Hazard analysis and critical control point (HACCP) and hygiene control auditing in Irish beef abattoirs

      Bolton, Declan J.; Pearce, Rachel; Tergny, Annabel; Howlett, Brendan (Teagasc, 2007-06)
      This project validated two innovative technologies for use in improving the safety of Irish beef. Online monitoring was developed and successfully tested as a tool for controlling faecal contamination on beef carcasses with the resultant reduction in microbial counts. A novel anti-microbial, LactiSAL®, was also tested and validated for use in the beef industry. Sponge swabbing using a polyurethane sponge was developed and validated for use in carcass testing as required in European Commission Decision 2001/471/EC. The costs of developing and implementing a HACCP system in Irish beef slaughter plants were assessed. Furthermore, a guide to relevant food safety legislation, including the development and auditing of HACCP and prerequisites for beef slaughter (in compliance with 2001/471/EC and the European Commission Hygiene Regulations), was developed and published.
    • High Pressure Processing of Dairy Foods

      Donnelly, W.J.; Beresford, Tom; Lane, C.N.; Walsh-O'Grady, D.; O'Connor, Paula M.; Fitzgerald, Richard J.; Murphy, P.M.; O'Reilly, Conor; Morgan, S.M.; Ross, R Paul; et al. (Teagasc, 2000-09-01)
      The term High Pressure Processing (HPP) is used to describe the technology whereby products are exposed to very high pressures in the region of 50 - 800 MPa (500 - 8000 Atmospheres). The potential application of HPP in the food industry has gained popularity in recent years, due to developments in the construction of HPP equipment which makes the technology more affordable. Applying HPP to food products results in modifications to interactions between individual components, rates of enzymatic reactions and inactivation of micro-organisms. The first commercial HPP products appeared on the market in 1991 in Japan, where HPP is now being used commercially for products such as jams, sauces, fruit juices, rice cakes and desserts. The pioneering research into the application of HPP to milk dates back to the end of the 19th century. Application of HPP to milk has been shown to modify its gel forming characteristics as well as reducing its microbial load. HPP offers the potential to induce similar effects to those generated by heat on milk protein. Recent reports have also indicated that HPP could accelerate the ripening of cheese. Much of the Irish cheese industry is based on the production of Cheddar cheese, the ripening time for which can vary from 4 - 12 months or more, depending on grade. A substantial portion of the cost associated with Cheddar manufacture is therefore attributed to storage under controlled conditions during ripening. Thus, any technology which may accelerate the ripening of Cheddar cheese while maintaining a balanced flavour and texture is of major economic significance. While food safety is a dominant concern, consumers are increasingly demanding foods that maintain their natural appearance and flavour, while free of chemical preservatives. HPP offers the food industry the possibility of achieving these twin goals as this technology can lead to reduced microbial loads without detrimentally effecting the nutritional or sensory qualities of the product. The development of food ingredients with novel functional properties offers the dairy industry an opportunity to revitalise existing markets and develop new ones. HPP can lead to modifications in the structure of milk components, in particular protein, which may provide interesting possibilities for the development of high value nutritional and functional ingredients. Hence these projects set out to investigate the potential of HPP in the dairy industry and to identify products and processes to which it could be applied.
    • High pressure technology in the manufacture of minimally-processed meat products

      Troy, Declan J.; Crehan, Clodagh; Mullen, Anne Maria; Desmond, Eoin (Teagasc, 2001-07)
      High hydrostatic pressure processing was applied to raw minced meat prior to product formulation and the results indicate that with 50 MPa pressure it was possible to reduce the salt in frankfurters from 2.5% to 1.5% without compromising the safety and overall quality. Similarly the phosphate content of frankfurters could be reduced from 0.5% to 0.25% after pressure treatment. Cook loss from the treated frankfurters was significantly reduced indicating a higher yield of product due to the high pressure.
    • 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.
    • Identification of the key compounds responsible for Cheddar cheese flavour

      Beresford, Tom; Wallace, J.; Aherne, Seamus; Drinan, Finbarr; Eason, D.; Corcoran, M.O.; Mulholland, E.; Hannon, John A. (Teagasc, 2000-09-01)
      There is a poor understanding of the relationship between organoleptic assessment of cheese and quantitative analysis of flavour compounds. Further, the contribution of particular cheese-making parameters such as ripening temperature and starter culture has not been fully elucidated. During the ripening of most cheese varieties complex chemical conversions occur within the cheese matrix. In most cheese varieties breakdown of protein is the most important flavour development pathway. The primary cheese protein, casein, is degraded enzymatically to short peptides and free amino acids. The agents primarily responsible for these conversions are the residual rennet that is retained in the cheese curd at the end of the manufacturing phase and the proteinases and peptidases that are associated with the starter bacteria. While the rate and degree of proteolysis are of vital significance for desired flavour development, the direct products of proteolysis do not fully define cheese flavour. Much research is now demonstrating that the further biochemical and chemical conversions of the products of proteolysis, in particular the amino acids, are necessary for full flavour development. The products produced by these pathways are volatile at low boiling points and are thus released during mastication of the cheese in the mouth. Many of these volatile compounds contribute to the flavour sensation experienced by the consumer. A very wide spectrum of such compounds have been isolated from cheese, in excess of two hundred in some cheese varieties. It is now generally accepted that there is no individual compound which defines cheese flavour completely and that the flavour sensation is the result of numerous compounds present in the correct proportions. This has become known as the Component Balance Theory . The application of modern analytical techniques as proposed in this project would provide a greater understanding of the significant flavour compounds in Cheddar cheese and help to identify the impact of specific cheese-making parameters such as starter flora and ripening temperature on the production of volatile flavour compounds. This data would assist the general programme on flavour improvement of cheese which should ultimately benefit the cheese manufacturer. Hence this project set out to develop methods to identify the key flavour compounds in Cheddar cheese. These techniques would then be applied to experimental and commercial cheeses during ripening in an effort to identify key compounds and the influence of starter cultures and ripening temperature on their production.
    • Improved Food Safety through Sterility of Air in Food Processing and Packaging.

      O'Callaghan, Donal; Murphy, P.; Lynch, Denise B; Coleman, S. (Teagasc, 1999-06-01)
      The aims of this research were to develop reliable methods for evaluating the level of airborne micro-organisms in food processing facilities and to study the viability and behaviour of micro-organisms in air filtration systems. The main conclusions were as follows: · Assessment of air quality involves monitoring both particulate and microbial levels as there is no simple relationship between these phenomena in a food process environment. · The large fluctuations in microbial levels found in air in these studies underline the necessity of frequent and regular air sampling in processing facilities. · It was established that micro-organisms can grow inside an air filter under certain environmental conditions and give rise to intermittent microbial germ contamination of the cleaned air. · It was demonstrated that flowing air affects the survival of microorganisms and the survival rate is dependent on filter class. Hence more emphasis on filter design aimed at effective microbial control is advised. · A combined system for filtering and sterilisation by ozone was demonstrated to be an efficient technique for extending the microbial separation efficiency of air filters.
    • Improving the quality of gluten-free products

      Gallagher, Eimear; McCarthy, Denise; Gormley, Ronan T.; Arendt, Elke (Teagasc, 2004-03)
      The incidence of coeliac disease or other allergic reactions/intolerances to gluten is increasing, largely due to improved diagnostic procedures and changes in eating habits. The worldwide number of sufferers of coeliac disease has been predicted to increase by a factor of ten over the next number of years, resulting in a growing market for gluten-free cereal-based products. Market research has shown that many of the products currently on sale are of inferior quality. The replacement of gluten presents a major technological challenge, as it is an essential structure-building protein which is necessary for formulating high quality cereal-based goods. Therefore, the production of high quality gluten-free bread is difficult.
    • Improving the Quality of Low Fat Cheddar Cheese

      Guinee, Timothy P.; Fenelon, Mark A.; O'Kennedy, Brendan; Mulholland, E. (Teagasc, 1999-02-01)
      The aims of this study were to elucidate the contribution of fat to cheese biochemistry and texture and to improve the texture and flavour of half-fat Cheddar cheese by modifications in make procedure, the addition of a fat mimetic, and/or the use of novel starter cultures/bacterial culture adjuncts. The main conclusions were as follows: A 'Moorepark Process' has been established for the production of half-fat Cheddar cheese with improved sensory acceptability. The flavour and texture of half-fat (17% w/w) Cheddar was improved by modification of the cheesemaking procedure and/or ripening conditions and through the use of novel starter cultures and/or bacterial culture adjuncts. Extensive databases have been compiled on: the effects of fat on the compositional, microbiological, biochemical, rheological and sensory properties of, and the yield of, Cheddar cheese. the compositional, biochemical and sensory characteristics of commercial Cheddar cheeses of different fat levels, available on the Irish and UK markets. Reduction in the fat level of Cheddar cheese resulted in a marked deterioration both in texture and flavour due to: increases in cheese hardness and fracture stress, indicating that the cheese became more elastic, tough and less amenable to mastication. a higher ratio of secondary-to-primary proteolysis a reduction in the level of primary proteolysis and an increase in the concentration of hydrophobic peptides which are conducive to bitterness.
    • Indicator organisms to determine the use of chilling as a critical point in beef slaughter HACCP

      Prendergast, Deirdre M.; Sheridan, James J.; Downey, Gerard (Teagasc, 2008-11)
      During chilling, temperatures of carcass surfaces at different sites change over time as do other parameters such as water activity (aw), the structure of the muscle and other tissues, as the carcass enters rigor mortis. Many of these factors are known to have a major effect on cell survival and growth and must be considered in determining the influence of chilling on bacterial survival on carcass surfaces. This study aimed to determine if chilling could be used as a critical control point (CCP) in beef slaughter in relation to pathogens such as E. coli O157:H7 and L. monocytogenes, using E. coli and Listeria innocua as pathogen indicators. The present study was designed to determine the influence of (a) chilling at 10oC for 72 h on the survival of E. coli and (b) chilling at 4oC for 72 h on the survival of L. innocua inoculated at different sites on beef carcasses. Three sites (neck, outside round and brisket) were inoculated (1) immediately after dressing while hot (E. coli and L. innocua) and (2) when cold after chilling (L. innocua). The influence of changes in surface aw was also considered and their relationship to the survival of E. coli and L. innocua over time was assessed. The data are discussed in relation to the use of chilling as a CCP in beef hazard analysis (HACCP) and the monitoring of neck temperature as the most suitable CCP.
    • Indicator organisms to determine the use of chilling as a critical point in beef slaughter HACCP

      Prendergast, Deirdre M.; Sheridan, James J.; Downey, Gerard (Teagasc, 01/11/2008)
      During chilling, temperatures of carcass surfaces at different sites change over time as do other parameters such as water activity (aw), the structure of the muscle and other tissues, as the carcass enters rigor mortis. Many of these factors are known to have a major effect on cell survival and growth and must be considered in determining the influence of chilling on bacterial survival on carcass surfaces. This study aimed to determine if chilling could be used as a critical control point (CCP) in beef slaughter in relation to pathogens such as E. coli O157:H7 and L. monocytogenes, using E. coli and Listeria innocua as pathogen indicators. The present study was designed to determine the influence of (a) chilling at 10oC for 72 h on the survival of E. coli and (b) chilling at 4oC for 72 h on the survival of L. innocua inoculated at different sites on beef carcasses. Three sites (neck, outside round and brisket) were inoculated (1) immediately after dressing while hot (E. coli and L. innocua) and (2) when cold after chilling (L. innocua). The influence of changes in surface aw was also considered and their relationship to the survival of E. coli and L. innocua over time was assessed. The data are discussed in relation to the use of chilling as a CCP in beef hazard analysis (HACCP) and the monitoring of neck temperature as the most suitable CCP.
    • Influence of Enterococci and Thermophilic Starter Bacteria on Cheddar Cheese Flavour

      Beresford, Tom; Cogan, Tim; Wallace, J.; Drinan, D.; Tobin, S.; Piveteau, P.; Carroll, N.; Deasy, B. (Teagasc, 1998-09-01)
      This project set out to identify suitable enterococci and thermophilic starter strains which could be added to the cheese during manufacture (as starter adjuncts) with the specific aims of enhancing flavour during ripening as well as facilitating flavour diversity - a trait sought by many commercial Cheddar companies. This project confirmed the potential of thermophilic lactic acid strains to affect flavour when used as starter adjuncts in Cheddar cheese manufacture. Their use can also lead to the development of novel flavours. Many adjunct cultures proposed to-date to enhance Cheddar flavour are composed of strains of lactococcal starter, selected for their flavouring capacity. However, application of such strains in industry would lead to increased probability of phage attack on the primary starter. On the other hand, thermophilic lactic acid strains are phage unrelated to conventional starter and thus would not lead to the introduction of starter specific phage into the cheese plant. A thermophilic strain from the Moorepark collection (DPC 4571) was shown to have major commercial potential as a flavour enhancer.