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Featured news / 4 August 2009 / Synbiosys
Synbiosis, a world-leading manufacturer of automated microbiological systems, is proud to announce its new multi-application ProtoCOL UV; automated colony counting and zone measurement system is now available. This high specification system will ensure scientists save hours by rapidly, and accurately counting colonies or imaging zones illuminated by UV or white light. (more…)
Featured news / 11 July 2009 / Neogen Europe
Neogen Europe Ltd. announced the introduction of a new immunoaffinity column for the analysis of deoxynivalenol (DON, vomitoxin) in a range of foods by high performance liquid chromatography (HPLC), ELISA, GC-MS and other analytical methods. (more…)
Issue 2 2009 / 1 June 2009 / Mieke Uyttendaele and Andreja Rajkovic, Laboratory of Food Microbiology and Food Preservation, Ghent University
Microbial analysis in foods is an integrated part of management of microbial safety in the food chain. Both competent authorities and individual food business operators use microbial analysis for monitoring of the actual situation and trend analysis in order to detect emerging risks. For compliance testing to defined microbiological criteria or assessment of the performance of management strategies based upon HACCP, microbial analysis is also a valuable tool. Molecular techniques, especially the polymerase chain reaction (PCR), are one of the most important rapid methods for the sensitive and specific detection of pathogenic micro-organisms.
The PCR technique, first described by Kary Mullis in the mid-1980s is a three-step cyclic in vitro procedure based on the ability of the DNA polymerase to copy a strand of DNA. When two primers bind to complementary strands of target DNA, the sequence in between is amplified exponentially with each cycle making the technique a very sensitive tool. The presence of even one copy of the template within the reaction mixture can be detected within a couple of hours as approximately a million-fold of copies are created. The results of PCR are traditionally (conventional PCR) detected by agarose gel electrophoreses and staining and specificity of the bands may be further identified by sequencing. In the early 1990’s, the ‘second’ generation of PCR technologies was introduced by the use of fluorescent double stranded DNA dyes e.g. SYBR@ Green or DNA probes e.g. Molecular beacons® or TaqMan® probes. Real-time PCR enables both the on-line detection (Figure 1) and quantification of the amplification product signal by continuously measuring a fluorescent reporter during the PCR reaction. The potential application of PCR also in routine labs was boosted not only the fact that PCR is no longer a black box reaction but also the fact that real-time PCR consists of a closed-tube format, reducing the risk of contamination potentially leading to false-positive results. (more…)
Issue 2 2009 / 1 June 2009 / Matthieu Adam-Berret and François Mariette, Cemagref & Université européenne de Bretagne
Fats are present in most food products and they have a significant importance for fat-containing products such as chocolate and butter. The physical properties of fats depend on the polymorphic behaviour and inter-solubility of their major triacylglycerol components and the phase behaviour of these mixtures is of paramount importance for the food industry. Indeed, fat structures formed by their crystals determine the functional properties of fat-containing products such as their texture, plasticity and morphology. DSC and XRD are the two techniques generally used to characterise fats. Crystal size is another important parameter for determining the physical properties of fats because it affects the rheological properties and consequently modifies taste, graininess and texture.
The use of low-field NMR spectrometers in the food industry began in the 1970’s with the commercial availability of the first bench-top NMR systems. Several applications were developed during the following years, but they were limited to the determination of water and fat content and measurement of the solid fat index. Surprisingly, the number of applications did not increase much during the following twenty years. In 1992, the first International Conference on Applications of Magnetic Resonance in Food Science was organised and since that time, with the improvements in bench-top NMR characteristics, new applications have been put forward. One of the most well-known is droplet size measurement based on diffusion coefficient measurements. The use of NMR relaxation times was suggested, not only for determining water and fat content but also for investigating food structure. Furthermore, NMR is a non-destructive technique and can be used to perform dynamic measurements, for example with changing temperatures or for studies relating to storage time. (more…)
Issue 2 2009 / 1 June 2009 / Jeroen Willemsen, Manager Business Development, Food Technology Centre, Wageningen UR and Verena Eisner Researcher Separation Technology, Food Technology Centre, Wageningen UR
Consumer expectations of product quality for food emulsions drive the industry to continuously invest in new production methods. Membrane emulsification (ME) has been known for many years and its potential is emphasised in numerous scientific publications. ME is said to ensure highly controlled production of particulates and be a more energy efficient process than conventional methods. Scientific developments in this area cover the production of oil-in-water (O/W) or water-in-oil (W/O) emulsions to multiple emulsions of different types, solid-in-oil-in-water (S/O/W) dispersions, coherent solids (silica particles, solid lipid microspheres) and structured solids (solid lipid microcarriers, gel microbeads).
Modifications of the base technique even extend the capabilities into different membrane materials and operation methods (rotating membrane, oscillating membrane). Nevertheless, the step to industrial applications is not yet fulfilled and appears more difficult than expected.
In this article, the fact that this high potential technique has not yet become a standard method in industrial processes of food products is discussed and specific activities to handle the challenges and hesitations at potential customers are proposed. (more…)
Featured news / 16 April 2009 / Oxoid
Oxoid, a world leading microbiology brand, has announced that the ELISA Systems range of quick and easy-to-use food allergen tests kits is now available alongside the Oxoid range. (more…)
Issue 1 2009 / 20 February 2009 / Gerard Downey, Principal Research Officer, Teagasc, Ashtown Food Research Centre
Globalisation has been a significant factor behind the financial meltdown in which we all find ourselves now, but it has also led to significant changes in the variety and origin of the foodstuffs which line our supermarket shelves. In previous articles, I have discussed some analytical responses to the concerns which consumers have regarding claims made on the labels of processed foods; fingerprint technologies, such as near infrared spectroscopy, possess specific features which make them well-suited for deployment to address at least some of these concerns. The focus of this article is on the appropriate chemometric strategy to deploy in the confirmation or determination of issues of the provenance of a food or food ingredient.
Provenance may be linked to the geographic origin of the food or to the method of its production. In European countries, there is a strong belief in the link between the quality of a given food and its geographic provenance; an example of this is in the French concept of terroir. In any case, in an effort to increase market growth and profitability, many food producers are making claims for the provenance of their products which allow them to charge a premium price. The basis for some of these claims is recognised in EU legislation, which defines specific terms that may be used by producers of certain foods in particular, defined geographic regions within Europe. These are Protected Denomination of Origin (PDO), Protected Geographical Indication (PGI) and Traditional Speciality Guaranteed (TSG). (more…)
Issue 1 2009 / 20 February 2009 / Michael Sulyok, Rainer Schuhmacher & Rudolf Krska, Centre for Analytical Chemistry, Department for Agrobiotechnology, IFA Tulln, University of Natural Resources and Applied Life Sciences Vienna
Since the introduction of atmospheric pressure ionisation liquid chromatography-mass spectrometry (API-LC-MS) in the early 1990s, there was a continuous effort to further improve the performance of the LC-MS instruments concerning sensitivity and robustness. One result of this development is the trend towards methods that are designed to simultaneously analyse a large number of analytes with little or even without any sample clean-up and/or analyte enrichment. It is evident that this approach exhausts the capabilities of the mass spectrometers to the extreme. In this article, the difficulties that are usually encountered during the development of such a multi-analyte method are discussed using the example of mycotoxins.
Mycotoxins are secondary metabolites that are produced by moulds upon the infection of grains, fruits and vegetables as well as processed food. Another route of exposure is the inhalation of mycotoxin-containing fungal spores in damp indoor environments. From the approximately 300-400 substances that are currently recognised as mycotoxins, only a few are addressed by legislation e.g. in Commission Regulation 1881/2006. Even these few compounds exhibit a considerable chemical diversity (Figure 1) ranging from polar (e.g. deoxynivalenol, patulin) to apolar (zearalenone) and acidic substances (fumonisins). In addition, not all of these substances are UV-active or fluorescent. This certainly complicates matters considering a simultaneous detection of these compounds and has therefore led to a large number of analytical methods dealing only with one compound class, which often includes a dedicated clean-up (reviewed1). However, this approach results in an enormous expenditure of time and costs if a sample has to be tested for several classes of mycotoxins. (more…)
Issue 4 2008 / 3 December 2008 / Dr Suzanne Jordan, Molecular Methods Manager, Campden BRI
Yeasts are a diverse range of organisms, many of which are beneficial to the food and drinks industry in fermentation and the flavour development of dairy, meat and beverage products. There are also strains that spoil products, resulting either in blowing packs or off odours and flavours.
It is difficult to approximate the financial losses to the industry caused by spoilage, and there are no published figures available for the United Kingdom. In Australia, the calculated losses due to fungal spoilage are reported to be AUD 10,000,000 per annum1. Recent reports indicate that 20 per cent of UK domestic waste taken to landfill was spoiled, unused or leftover food2.
A range of techniques are available to assist the industry in answering questions, such as identifying spoilage organisms, determining culture authenticity and tracking sources of contamination. Identification provides a name for an unknown organism to either genus or species level and can be used to search for information on spoilage or safety issues and highlight the potential for resistance to preservation strategies. Characterisation allows organisms that share similar characteristics, such as DNA fragment profile, to be placed into groups, which assists in determining potential sources of contamination. These techniques can be divided into two groups based on their approach, i.e. biochemical and molecular based assays. (more…)
Issue 4 2008 / 3 December 2008 / Leon Coulier & William van Dongen, TNO Quality of Life and Emma Bradley & Laurence Castle Central Science Laboratory, York
Many new developments in analytical chemistry are driven by needs for life science applications. Examples are the various –omics technologies, i.e. genomics, transcriptomics, proteomics and metabolomics and the use of isotope labelling. Food analysis is often thought to be less complex when one thinks of the determination of specific contaminants or nutrients in food, for example. However, there are cases when highly advanced analytical technologies are necessary.
An excellent example of this is bisphenol A diglycidyl ether (BADGE, Figure 1, see page 18). BADGE is an epoxide used to make can coatings. Commission Regulation No. (EC) 1895/20051 places migration limits on selected substances used in the production of epoxy can coatings. Testing for compliance with these limits can be carried out using so-called food simulants, which are solvents that mimic certain food types, and this testing is rather straightforward.
Much more complex is the reaction chemistry of BADGE in certain foods after migration takes place. The most simple of these reactions is with water to form the hydrolysis products denoted BADGE.H2O and BADGE.2H2O. There are other reaction pathways available however, including with some food amino acids2,3 but in many cases the migrated BADGE still cannot be accounted for fully. This is important because if BADGE migrates into the food but is then transformed chemically into other species, the potential hazard that these other chemicals may present should be assessed. To do this, they have to be identified. (more…)
Issue 4 2008 / 3 December 2008 / NF
Applications of nanotechnology in the food industry mean different things to different people and this influences the perception of benefits and risks of nanotechnology. Nanotechnology is not a discrete area, but rather a broad spectrum of applications concerned with the rational modification of food structures at the molecular or macromolecular level, or the introduction of nanoparticles or nanostructures into foods.
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Issue 3 2008, Past issues / 18 August 2008 / Dr Hanne Christine Bertram. Senior Project Scientist, University of Aarhus
Water is a major constituent in many foods. For example, in several of our basic food items such as muscle-based foods and vegetables, water is the dominating component and is in many ways of primary importance for the quality of these products. Low-field proton NMR relaxometry is an excellent technique for studying water properties in complex systems such as food.
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Issue 3 2008, Past issues / 18 August 2008 / S.J. Millar, M.B. Whitworth, A. Chau, Campden & Chorleywood Food Research Association and J.R. Gilchrist, Gilden Photonics Ltd
Near infrared (NIR) spectroscopy is widely used in the global agri-food industry for the non-destructive assessment of both the compositional and physical characteristics of a wide range of raw materials and finished products. This is particularly so in the cereals and related industries where, following the commercial development of suitable NIR instrumentation in the 1970s, the technique rapidly became the main means of determining a range of compositional properties which form the basis of trading operations worldwide.
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Featured news / 15 August 2008 / Synbiosys
Synbiosis, a world-leading manufacturer of automated microbiological systems, is delighted to announce the availability of new ProtoCOL software for automatic colony and inhibition zone analysis, as well as full validation information for its entire range of automated colony counters. The combined use of software and validation protocols will provide a vital link in the quality chain. (more…)
Issue 2 2008, Past issues / 13 June 2008 / J. P. M. van Duynhoven, Gert-Jan W. Goudappel, Elena Trezza, Adrian M. Haiduc, Franck Duval, Wladyslaw P. Weglarz, Unilever Food and Health Research Institute, Vlaardingen, The Netherlands
NMR is a versatile tool for structural assessment of food materials and this pertains in particular for its benchtop and hand-held implementations. Such “small NMR” equipment can literally be deployed in all phases of foods innovation. This is illustrated by several industry examples.
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