Hapten synthesis and antibody production for the development of a melamine immunoassay

The incorporation of melamine into food products is banned but its misuse has been widely reported in both animal feeds and food. The development of a rapid screening immunoassay for monitoring of the substance is an urgent requirement. Two haptens of melamine were synthesized by introducing spacer arms of different lengths and structures on the triazine ring of the analyte molecular structure. 6-Aminocaproic acid and 3-mercaptopropionic acid were reacted with 2-chloro-4,6-diamino-1,3,5-triazine (CAAT) to produce hapten 1[3-(4,6-diamino-1,6-dihydro-1,3,5-triazin-2-ylamino) hexanoic acid] and hapten 2[3-(4,6-diamino-1,6-dihydro-1,3,5-triazin-2-ylthio) propanoic acid]. respectively. The molecular structures of the two haptens were identified by I H nuclear magnetic resonance spectrometry, mass spectrometry and infrared spectrometry. An immunogen was prepared by coupling hapten 1 to bovine serum albumin (BSA). Two plate coating antigens were prepared by coupling both haptens to egg ovalbumin (OVA). A competitive indirect enzyme-linked immunosorbent assay (ciELISA) was developed to evaluate homogeneous and heterogeneous assay formats. The results showed that polyclonal antibodies with high titers were obtained, and the heterogeneous immunoassay format demonstrated a better performance with an IC50 of 70.6 ng mL(-1), a LOD of 2.6 ng mL(-1) and a LOQ of 7.6 ng mL(-1). Except for cyromazine, no obvious cross-reactivity to common compounds was found. The data showed that the hapten synthesis was successful and the resultant antisera could be used in an immunoassay for the rapid and sensitive detection of this banned chemical. (C) 2010 Elsevier B.V. All rights reserved.

Trading-up on unmet expectations? Evaluating consumers’ expectations in online premium grocery shopping logistics

Geography and retail store location are inherently bound together; this study links food retail changes to systemic logistics changes in an emerging market. Current logistic practices underplay demand-led models and online market evolution in large metropolises such as Istanbul, Rio de Janeiro, and Delhi. The later include raising income and education, access to a wide range of technologies, traffic and transport difficulties, lagging retail provision, changing family structure and roles, as well as changing food culture and taste. The study incorporates demand for premium products defined by Kapferer and Bastien, (2009b) as comprising a broad variety of higher quality and unique or distinctive products and brands including in grocery organic ranges, healthy options, allergy free selections, and international and gourmet/specialty products through an online grocery model (n=356) that integrates a novel view of home delivery (HD) in Istanbul. More importantly from a logistic perspective our model incorporates any products from any online vendors broadening the range beyond listed items found in any traditional online supermarkets. Data collected via phone survey and analysed via structural equation modelling (SEM) suggest that the offer of online premium products significantly affects consumers’ delivery logistics expectations. We discuss logistics operations and business management implications, identifying the emerging geography of logistic models which respond to consumers’ unmet expectations using multiple sourcing and consolidation points.

Exploring the dilemma of local sourcing versus international development – the case of the flower industry

This paper examines the debate surrounding local versus international sourcing of retail products, particularly food and flowers, in light of the emerging carbon imperative. It begins by examining the Fairtrade market and then examines food miles and carbon impact. The complexity of sourcing decisions when considering both international development issues and the emerging carbon agenda is considered using the case of the cut flower industry

Development of a recombinant Fab-fragment based electrochemical immunosensor for deoxynivalenol detection in food samples

A reliable and cost-effective electrochemical method for the detection of deoxynivalenol (DON) in cereals and cereal-based food samples based on the use of a novel anti-DON Fab fragment is presented. The analytical system employed, Enzyme-Linked-Immunomagnetic-Electrochemical (ELIME) assay, is based on the use of immunomagnetic beads (IMBs) coupled with eight magnetized screen-printed electrodes (8-mScPEs) as electrochemical transducers.

Development of a high-throughput enzyme-linked immunosorbent assay for the routine detection of the carcinogen acrylamide in food, via rapid derivatisation pre-analysis

The spontaneous formation of the neurotoxic carcinogen acrylamide in a wide range of cooked foods has recently been discovered. These foods include bread and other bakery products, crisps, chips, breakfast cereals, and coffee. To date, the diminutive size of acrylamide (71.08Da) has prevented the development of screening immunoassays for this chemical. In this study, a polyclonal antibody capable of binding the carcinogen was produced by the synthesis of an immunogen comprising acrylamide derivatised with 3-mercaptobenzoic acid (3-MBA), and its conjugation to the carrier protein bovine thyroglobulin. Antiserum from the immunised rabbit was harvested and fully characterised. it displayed no binding affinity for acrylamide or 3-MBA but had a high affinity for 3-MBA-derivitised acrylamide. The antisera produced was utilised in the development of an ELISA based detection system for acrylamide. Spiked water samples were assayed for acrylamide content using a previously published extraction method validated for coffee, crispbread, potato, milk chocolate and potato crisp matrices. Extracted acrylamide was then subjected to a rapid 1-h derivatisation with 3-MBA, pre-analysis. The ELISA was shown to have a high specificity for acrylamide, with a limit of detection in water samples of 65.7 mu g kg(-1), i.e. potentially suitable for acrylamide detection in a wide range of food commodities. Future development of this assay will increase sensitivity further. This is the first report of an immunoassay capable of detecting the carcinogen, as its small size has necessitated current analytical detection via expensive, slower, physico-chemical techniques such as Gas or Liquid Chromatography coupled to Mass Spectrometry. (c) 2007 Elsevier B.V. All rights reserved.

Development of a simple gel permeation clean-up procedure coupled to a rapid disequilibrium enzyme-linked immunosorbent assay (ELISA) for the detection of Sudan I dye in spices and sauces

Sudan dyes have been found to be added to chilli and chilli products for illegal colour enhancement purposes. Due to the possible carcinogenic effect, they are not authorized to be used in food in the European Union or the USA. However, over the last few years, many products imported from Asian and African countries have been reported via the Rapid Alert System for Food and Feed in the European Union to be contaminated with these dyes. In order to provide fast screening method for the detection of Sudan I (SI), which is the most widely abused member of Sudan dyes family, a unique (20 min without sample preparation) direct disequilibrium enzyme-linked immunosorbent assay (ELISA) was developed. The assay was based on polyclonal antibodies highly specific to SI. A novel, simple gel permeation chromatography clean-up method was developed to purify extracts from matrices containing high amounts of fat and natural pigments, without the need for a large dilution of the sample. The assay was validated according to the Commission Decision 2002/657/EC criteria. The detection capability was determined to be 15 ng g(-1) in sauces and 50 ng g(-1) in spices. The recoveries found ranged from 81% to 116% and inter- and intra-assay coefficients of variation from 6% to 20%. The assay was used to screen a range of products (85 samples) collected from different retail sources within and outside the European Union. Three samples were found to contain high amounts (1,649, 722 and 1,461 ng g(-1)) of SI by ELISA. These results were confirmed by liquid chromatography-tandem mass spectrometry method. The innovative procedure allows for the fast, sensitive and high throughput screening of different foodstuffs for the presence of the illegal colorant SI.

Development of a rapid low cost fluorescent biosensor for the detection of food contaminants

A prototype fluorescent based biosensor has been developed for the antibody based detection of food related contaminants. Its performance was characterised and showed a typical antibody binding signal of 200-2000 mV, a short term noise of 9.1 mV, and baseline slope of -0.016 mV/s over 4 h. Bulk signal detection repeatability (n=23) and reproducibility (n=3) were less than 2.4%CV. The biosensor detection unit was evaluated using two food related model systems proving its ability to monitor both binding using commercial products and inhibition through the development of an assay. This assay development potential was evaluated by observing the biosensor's performance whilst appraising several labelled antibody and glass slide configurations. The molecular interaction between biotin and an anti-biotin antibody was shown to be inhibited by 41% due to the presence of biotin in a sample. A food toxin (domoic acid) calibration curve was produced, with %CVs ranging from 2.7 to 7.8%, and a midpoint of approximately 17 ng/ml with further optimisation possible. The ultimate aim of this study was to demonstrate the working principles of this innovative biosensor as a potential portable tool with the opportunity of interchangeable assays. The biosensor design is applicable for the requirements of routine food contaminant analysis, with respect to performance, functionality and cost. (C) 2012 Elsevier B.V. All rights reserved.

Development of small and medium-sized enterprise horizontal innovation networks: UK agri-food sector study

Within the management literature, there is an emergent discourse on horizontal collaboration among small and medium-sized enterprises (SMEs), whereby individual rivalries are overcome by the need for more resources and innovation, leading to increased competitiveness through joint product development. In particular, a number of these horizontal collaborations between SMEs have occurred within the agri-food sector. As a consequence, this article aims to explore the longitudinal development of horizontal innovation networks within an artisan bakers’ network as part of the UK SME agri-food sector. An interpretivist research approach was used, whereby the development and evolution of an artisan bakers’ horizontal network was studied over a 27-month period. The findings, as summarised in conceptual models which draw upon knowledge-based open innovation and social network constructs, illustrate that a complex three-stage life cycle development occurred within the bakers’ horizontal network.

Development and validation of a rapid multiplex ELISA for pyrrolizidine alkaloids and their N-oxides in honey and feed Rapid Detection in Food and Feed

Pyrrolizidine alkaloids (PAs) are a group of plant secondary metabolites with carcinogenic and hepatotoxic properties. When PA-producing plants contaminate crops, toxins can be transferred through the food chain and cause illness in humans and animals, most notably hepatic veno-occlusive disease. Honey has been identified as a direct risk of human exposure. The European Food Safety Authority has recently identified four groups of PAs that are of particular importance for food and feed: senecionine-type, lycopsamine-type, heliotrine-type and monocrotaline-type. Liquid or gas chromatography methods are currently used to detect PAs but there are no rapid screening assays available commercially. Therefore, the aim of this study was to develop a rapid multiplex ELISA test for the representatives of three groups of alkaloids (senecionine, lycopsamine and heliotrine types) that would be used as a risk-management tool for the screening of these toxic compounds in food and feed. The method was validated for honey and feed matrices and was demonstrated to have a detection capability less than 25 µg/kg for jacobine, lycopsamine, heliotrine and senecionine. The zinc reduction step introduced to the extraction procedure allows for the additional detection of the presence of N-oxides of PAs. This first multiplex immunoassay for PA detection with N-oxide reduction can be used for the simultaneous screening of 21 samples for >12 PA analytes. Honey samples (n?=?146) from various origins were analysed for PA determination. Six samples were determined to contain measurable PAs >25 µg/kg by ELISA which correlated to >10 µg/kg by LC-MS/MS.

Young children's food brand knowledge. Early development and associations with television viewing and parent's diet

Brand knowledge is a prerequisite of children's requests and choices for branded foods. We explored the development of young children's brand knowledge of foods highly advertised on television - both healthy and less healthy. Participants were 172 children aged 3-5 years in diverse socio-economic settings, from two jurisdictions on the island of Ireland with different regulatory environments. Results indicated that food brand knowledge (i) did not differ across jurisdictions; (ii) increased significantly between 3 and 4 years; and (iii) children had significantly greater knowledge of unhealthy food brands, compared with similarly advertised healthy brands. In addition, (iv) children's healthy food brand knowledge was not related to their television viewing, their mother's education, or parent or child eating. However, (v) unhealthy brand knowledge was significantly related to all these factors, although only parent eating and children's age were independent predictors. Findings indicate that effects of food marketing for unhealthy foods take place through routes other than television advertising alone, and are present before pre-schoolers develop the concept of healthy eating. Implications are that marketing restrictions of unhealthy foods should extend beyond television advertising; and that family-focused obesity prevention programmes should begin before children are 3 years of age.