• Ingredient Development using a Pilot-Scale Tall-Form Spray Drier

      Kelly, Philip M; Kelly, J.; Harrington, D. (Teagasc, 1998-02-01)
      The main objectives of the project were to establish relationships between process variables and product physicochemical/functional characteristics in the course of processing and drying new dairy-based ingredients such as high-fat and protein-rich products in regular and agglomerated forms. By establishing processing protocols, R&D users of the ingredient drying facilities of Moorepark Technology Ltd may be able to predict the process variables necessary for desired end-product specifications to be achieved, and thus make experimentation more efficient and cost effective, as well as facilitate small scale production runs and sample preparation for market development purposes. Particular emphasis was placed on the development of high fat cream and fat-filled powders, flavour-delivery systems and protein-enriched ingredients. The major achievement of this project is that it is now possible to confidently select the appropriate processing conditions during the spray drying of ingredients in order to attain desired end-product specifications. Based on the use of the newly-installed Tall-form drier, the project succeeded in correlating the effects of process parameters of this technicallyadvanced pilot plant with the physicochemical properties of powders containing varying fat (20-80%) and protein contents. In general, the physicochemical characteristics of fat-filled and cream-filled powders with similar fat contents were similar except for higher solubility index values (range 0.1-0.6) in the case of the former particularly in the range 26-28% fat. Furthermore, the free fat content of powders may now be controlled much more precisely using an appropriate combination of total fat, atomiser nozzle selection and post-drying blending.
    • Extending the shelf life of fresh sliced mushrooms

      Brennan, Martine H.; Gormley, Ronan T. (Teagasc, 1998-08)
      The Irish mushroom industry is expanding rapidly as is the demand for sliced mushrooms. To increase the competitiveness of Irish mushrooms for export their shelf life should be extended to compensate for the time lost in transit. The aim of this project was to extend the shelf life of sliced mushrooms by 50 % using novel processing treatments and / or packaging. A method was established to assess the effects of different treatments on mushroom quality. This method was followed using solutions of citric acid, hydrogen peroxide, EDTA, nisin, diacetyl, vitamin E, ascorbic acid, rosemary extracts and sodium metabisulphite.
    • 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.
    • Relating starch properties to boiled potato texture

      Gormley, Ronan T. (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.
    • Assessment of Food Ingredient Functionality using Laser Microscopy

      Keogh, M.K.; Auty, Mark (Teagasc, 1998-09-01)
      The objectives of this project were, to establish a confocal microscopy facility at Moorepark, to develop suitable methodology for the examination of food products and ingredients, to apply confocal microscopy techniques to food research projects and to use the above technological expertise for commercial applications in the Irish Food Industry. The confocal laser scanning microscopy (CLSM) facility is now established and is fully integrated into the Teagasc research program at Moorepark. The new Confocal Microscopy Service has attracted significant commercial interest and client work is expanding. Results show that confocal laser scanning microscopy is a valuable technique for assessing the functionality of food ingredients in a wide range of food products, as well as being a powerful problem-solving tool. Work is ongoing to develop further specific ingredient localisation techniques, and to promote commercial awareness of the service. Confocal laser scanning microscopy offers a unique contribution to product research and development in the Irish food industry.
    • Influence of Enterococci and Thermophilic Starter Bacteria on Cheddar Cheese Flavour

      Beresford, Tom; Cogan, T.; 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.
    • Use of Bacteriocins to Improve Cheese Quality and Safety

      Ross, R. Paul; Hill, Colin; Ryan, Maire; Cunniffe, Alan; McAuliffe, Olivia; Murray, Deirdre; O'Keefe, Triona; Rea, Mary (Teagasc, 1998-09-01)
      The objectives of this project were to generate, characterise and exploit a range of novel bacteriocin producing starter cultures to improve both the safety and the quality of fermented dairy foods. The main conclusions were as follows: Lacticin 3147 is a broad spectrum bacteriocin which inhibits a wide range of Gram-positive bacteria including lactobacilli, clostridia and Listeria. The bacteriocin has been purified by chromatographic procedures and has been shown to be composed of two peptides, both of which are required for biological activity. The mechanism of action of lacticin 3147 has been elucidated. The entire plasmid encoding lacticin 3147 has been sequenced and the bacteriocin in distinct from any previously characterised lactococcal bacteriocin. The Food Grade introduction of the bacteriocin genes into cheese starters was carried out. Lacticin 3147 producing starters have been used to control the pathogen Listeria monocytogenes on the surface of mould ripened cheese. Lacticin 3147 producing starters have been used to control the non-starter lactic acid bacteria complement in Cheddar cheese during the ripening process. A novel starter system using a bacteriocin (lactococcin)- producing adjunct has been designed which gives increased cell lysis during Cheddar cheese manufacture while ensuring that efficient acid production is not compromised. In summary these studies have found that naturally occurring antimicrobials such as bacteriocins have a wide range of applications in the food industry for improving both the quality and safety of fermented dairy products.
    • Dairy Ingredients in Chocolate

      Keogh, M.K.; O'Kennedy, Brendan; Twomey, M.; O'Brien, N.; Kennedy, B.; Gorry, C. (Teagasc, 1998-09-01)
      The main objective was to assess and control the contribution of various ingredient components to chocolate behaviour and to optimise ingredients for specific chocolate applications. A key aim, therefore, was to understand the role of composition and particle structure and to produce spray dried powders with a functionality in chocolate as close as possible to roller dried powders. By demonstrating how the powder properties affect chocolate, it should be possible to control the functional properties of the powders to meet any powder or chocolate specification. Novel powder compositions indicated by this work should also be useful to chocolate makers. The ability to make chocolate under test conditions and to assess the role of milk powders or other ingredients has been put in place for the first time in Ireland. Previous knowledge of milk seasonality and of powder technology has provided a basis for understanding variations in milk powder functionality in chocolate. Spray dried powders with mean free fat values of 50 to 94%, particle sizes of 30 to 65 mm and vacuole volumes of 0.0 to 3.9 ml/100g were produced from milks of varying composition but under the same processing conditions. Advances were made in analysing powder structure through microscopy, particle size and occluded air measurement. Valuable new information has been generated on the changes in free fat, solid fat content, particle size and occluded air in powders. Explanations were provided for the first time for the complex effects of these properties on chocolate viscosity and yield value. This information will also make a positive contribution to other projects in the milk powder area. Good contacts have been established with multinational manufacturers and with producers of milk powder for chocolate.
    • Development of a Range of Encapsulated Milk Fat Products

      Keogh, M.K.; O'Kennedy, Brendan; Neville, D.P.; Kennedy, B.; Gorry, C. (Teagasc, 1998-09-01)
      The aims of this research were to determine the effects of milk composition (fat, whey protein, lactose and salts) and process (homogenisation) factors on the formation of emulsions and microencapsulated powder particles and to relate these to the properties of the powder, especially susceptibility to fat oxidation. The effect of composition, using sodium caseinate and lactose on the production of high fat powders was also studied. Finally, new developments in microencapsulated milk powders were undertaken in collaboration with industry using sodium caseinate and lactose. Overall, the microencapsulation process should provide a technique to extend the shelf-life of sensitive fats and flavours and to produce high fat powders for a range of end-uses. The major components of the emulsions used to make the microencapsulated powders influenced fat globule diameter and stability, but the minor salt components also affected globule size and stability. Free flowing high fat (70%) powders with sodium caseinate and lactose as encapsulants were manufactured using a tall-form Niro spray dryer with fluidised beds. A flavoured ingredient using a by-product flavoured fat as the flavour agent was made using the same encapsulants. Microencapsulated powders were incorporated into baked goods as multi-functional ingredients. They increased loaf volumes and improved handling and processability of the dough, thereby extending the product range for fat and other dairy ingredients used for baking. Microencapsulated 80% fat blends were manufactured for biscuit formulations to overcome the handling problems associated with bulk fats. This sub-project also gave rise to a leading role in a EU FAIR project on the microencapsulation of fish oil for use in functional foods using milk components as the sole encapsulants.
    • Development and Evaluation of Caseins/Caseinates for use as Ingredients in Food Products

      Mehra, Raj; Walsh, Daniel; O'Kennedy, Brendan; Kelly, Phil (Teagasc, 1998-09-01)
      The overall objective of this project was to investigate the effects of key processing steps in the industrial production of acid casein on the characteristics and functionality of sodium caseinate with particular emphasis on analytical/functionality testing and seasonal/lactational effects on the original milk. The main conclusions were as follows: The most significant result indicates that drying and concentration after washing of the acid casein curd are responsible for alterations in the structure of casein, which result in sodium caseinates with different properties. This was confirmed in the case of two acid casein plants investigated which showed similar results even though using different washing and drying technologies. This difference due to the drying step may be further amplified depending upon whether commercial sodium caseinate is manufactured from acid casein in the dried or wet curd state. The analytical and functional testing methodology adapted in our laboratory proved effective in predicting the effects of processing steps on the functionality of sodium caseinate. In particular, the ability to detect the presence of aggregate formation was particularly important. The database generated subsequently helped an acid casein manufacturer in modifying its process(es) to manufacture experimental sodium caseinate for specific food end-uses. Progress was greatly facilitated by the collaboration of individual manufacturers in the sourcing of problem samples from previously manufactured codes, and facilitating access to process plant during production. In a commercial application of the database, confidential work was undertaken on behalf of a client. Experimentally-produced sodium caseinate ingredients were evaluated using our adapted functionality testing methods and based on the results, the company was able to modify its process(es) to produce sodium caseinates with functionality for specific food end-users. It was concluded that while processing parameters in the production of acid casein can have a significant effect on the functional behaviour of the resultant sodium caseinate, the ability to assess this change in functional behaviour, through relevant functional testing, was equally important.
    • Establishment of Enabling Technology for Manufacture of Selected Types of Continental and Speciality Cheeses

      Wilkinson, M.G.; Sheehan, Jeremiah J.; Guinee, Timothy P.; Cogan, T.M. (Teagasc, 1998-09-01)
      The objectives in the project were the development of the science and technology for speciality cheese manufacture, identification and overcoming of the technical constraints to the manufacture of soft speciality cheeses in Ireland and the development of Moorepark Technology Limited (MTL) pilot plant as an integrated, flexible pre-commercial manufacturing platform with which to evaluate the market for speciality cheese.
    • 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.
    • The ultra-rapid chilling of lamb carcasses

      McGeehin, Brian; Sheridan, James J. (Teagasc, 1999-01)
      The practice in Irish commercial abattoirs is to chill lamb carcasses for a period of approximately 16 hours at 2 - 4°C, at which stage the core temperature of the carcass has reached 7°C. Chilling in this manner is considered necessary because it is generally held that faster chilling leads to toughening of the meat. The objective of this work was to develop a continuous ultra-rapid chilling system for lambs which would reduce carcass chilling time without adversely affecting the quality of the meat.
    • 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.
    • Development of HACCP analysis systems for beef slaughter

      Doherty, Alice M.; McEvoy, John M.; Sheridan, James J.; McGuire, Liam; O'Sullivan, Marian (Teagasc, Ballsbridge, Dublin 4, 1999-01)
      The aim of this study was to establish the types and levels of bacterial contamination on beef carcasses slaughtered under commercial conditions. This information is necessary as baseline data for the implementation of a Hazard Analysis Critical Control Point (HACCP) plan in a meat factory. Samples were taken over a twelve month period from five carcass sites representing the fore and hind quarters of the carcass. These included the hock, bung, inside round, cranial back and brisket. The carcasses were sampled at different stages of dressing namely legging, hide removal, evisceration, carcass splitting, carcass washing and chilling (24 h later). Four meat cuts (inside round, outside round, chuck roll (cranial back) and brisket) were also sampled after boning. Counts were enumerated for the following groups of bacteria: total bacterial counts (25°C and 4°C); pseudomonad counts (25°C and 4°C); E nterobacteriaceae counts; E scherichia coli O157:H7 and L isteria spp.
    • Wheat flour properties and end product quality

      Dwyer, Elizabeth; O'Halloran, Grainne R. (Teagasc, 1999-01)
      For pizza production, the flour quality values identified for the wheat cultivars, Promessa, Quintus (spring), and Soissons (winter) should be used as guidelines in selecting new cultivars and in the development of flour specifications. Similarly for biscuit production, compositional and rheological data for the cultivars, Riband,Woodstock (soft-milling) and Brigadier (hardmilling) should be used for identifying biscuit flours. The rheological properties of dough (as measured by the alveograph, extensograph and farinograph) did not relate to the baking quality for some wheat cultivars. However the rheological properties of the gel protein prepared from these flours explained their baking quality. The very high elastic moduli of these gels explained the basis of shrinkage of pizza bases produced from Baldus and Lavett flours and biscuits produced from Ritmo flour.
    • Methods for veterinary drug residue analysis in food

      O'Keeffe, Michael (Teagasc, 1999-02)
      A comprehensive capability to test for residues of veterinary drugs is an important support for the Irish food industry. There is a requirement for food manufacturers to demonstrate the compliance of their products with stringent customer specifications. In addition, legislative requirements are becoming more exacting both in terms of the range of substances covered and the lower residue levels to which test systems must measure.
    • New technologies in the manufacture of low fat meat products

      Allen, Paul; Dreeling, Niamh; Desmond, Eoin; Hughes, Eimear; Mullen, Anne Maria; Troy, Declan J. (Teagasc, 1999-02)
      The objective of this project was to provide a sound scientific basis for the development of low fat meat products. The emphasis was placed on identifying the barriers to producing high quality, low fat meat products and providing a knowledge base for manufacturers to overcome these, rather than actually developing new products. Each partner had specific tasks and worked with traditional products of their country. A wide range of products was thereby studied including comminuted, emulsion, cured and dried fermented, so that the results are widely applicable.
    • Enhancing the tenderness of beef

      Troy, Declan J. (Teagasc, 1999-02)
      This project investigated various methods which had potential to increase beef tenderness and was also aimed at elucidating the biochemical mechanism underlying the improved tenderness.