Food Allergen Analysis: Detection, Quantification and Validation by Mass Spectrometry

Worldwide, food-allergy-related diseases are a significant health problem. While the food industry works on managing cross-contaminations and while clinicians deal with treatment, laboratories must develop efficient analytical methods to ensure detection of hidden allergens that can cause severe adverse reactions. Over the past few years, huge progress has been made in mass spectrometry for the analysis of allergens in incurred and processed foodstuffs, especially as regards sample preparation and enrichment (solid phase extraction, protein precipitation and ultrafiltration). These achievements make it possible to meet the Allergen Bureau\u27s Voluntary Incidental Trace Allergen Labelling (VITAL) sensitivity criteria. The present chapter details the different steps in the development of mass spectrometry methods, from peptide selection to the validation of qualitative and quantitative methods. The chapter focuses mainly on studies performed with incurred and processed food samples to ensure the applicability of the methods to allergen detection in real food products

Highlight on Bottlenecks in Food Allergen Analysis:Detection and Quantification by Mass Spectrometry

Abstract Food laboratories have developed methods for testing allergens in foods. The efficiency of qualitative and quantitative methods is of prime importance in protecting allergic populations. Unfortunately, food laboratories encounter barriers to developing efficient methods. Bottlenecks include the lack of regulatory thresholds, delays in the emergence of reference materials and guidelines, and the need to detect processed allergens. In this study, ultra-HPLC coupled to tandem MS was used to illustrate difficulties encountered in determining method performances. We measured the major influences of both processing and matrix effects on the detection of egg, milk, soy, and peanut allergens in foodstuffs. The main goals of this work were to identify difficulties that food laboratories still encounter in detecting and quantifying allergens and to sensitize researchers to them.</jats:p

Accurate compound-specific 14C dating of archaeological pottery vessels

Pottery is one of the most commonly recovered artefacts from archaeological sites. Despite more than a century of relative dating based on typology and seriation, accurate dating of pottery by the radiocarbon method has proven extremely challenging due to the limited survival of organic temper and unreliability of visible residues. We report here a new method of dating directly archaeological pottery based on accelerator mass spectrometry (AMS) analysis of 14C in absorbed food residues: palmitic (C16:0) and stearic (C18:0) fatty acids purified by preparative gas chromatography (pcGC). We present the first accurate compound-specific radiocarbon determinations of lipids extracted from pottery vessels, which were rigorously evaluated by comparison with dendrochronological dates and inclusion in site and regional chronologies containing suites of radiocarbon dates on other materials . Critically, the compound-specific dates from each of the C16:0 and C18:0 fatty acids in pottery vessels provide an internal quality control of the results and, are entirely compatible with dates for other commonly dated materials. Accurate radiocarbon dating of pottery vessels can reveal: (i) the period of use of pottery; (ii) the antiquity of organic residues including when specific foodstuffs were exploited; (iii) sites chronologies in the absence of traditionally datable materials and (iv) direct verification of pottery typochronologies. As exemplars, the method was applied to the dating of dairy and carcass product exploitation in Neolithic vessels, from Britain, Anatolia, central and western Europe, and Saharan Africa.Additional co-authors: Christian Jeunesse, Marta Krueger, Arkadiusz Marciniak, Steve Minnitt, Rocco Rotunno, Pieter van de Velde, Ivo van Wijk, Jonathan Cotton, Andy Daykin, Richard P Evershe

Effets des radiations ionisantes sur des complexes ADN-protéine

La destruction radio-induite des complexes ADN-protéine peut avoir des conséquences graves pour des systèmes impliqués dans des fonctions cellulaires importantes. Le premier système qui a été étudié est un système de régulation de l'expression génique chez Escherichia coli, celui de l'opéron lactose. Le complexe répresseur-opérateur est détruit après l'irradiation du complexe ou de la protéine seule. L'endommagement du domaine de fixation du répresseur à l'ADN (appelé headpiece) a été démontré et étudié tant du point de vue de l'intégrité de la chaîne peptidique que de la conformation et des modifications de certains acides aminés. Dans un deuxième temps, des dysfonctionnements de l'induction d'un complexe répresseur irradié-opérateur non irradié ont été mises en évidence. Ces perturbations, dues à une diminution du nombre de sites de fixation sur le répresseur, sont corrélées à l'endommagement de résidus tryptophane. D'autre part, l'inducteur protège le répresseur lorsque ces deux partenaires sont irradiés ensemble, d'une part par capture (scavenging) des radicaux en solution et d'autre part par le masquage de son site de fixation sur la protéine. Le deuxième système étudié est formé par Fpg (ou Formamidopyrimidine glycosylase), protéine de réparation de l'ADN, et par de l'ADN porteur d'une lésion oxidative. Les résultats obtenus montrent que l'irradiation de la protéine perturbe la réparation à la fois en diminuant son efficacité de reconnaissance et de fixation des lésions, et en modifiant son activité enzymatique.ORLEANS-BU Sciences (452342104) / SudocSudocFranceF

Modification of DNA radiolysis by DNA-binding proteins: structural aspects

Formation of specific complexes between proteins and their cognate DNA modulates the yields and the location of radiation damage on both partners of the complex. The radiolysis of DNA-protein complexes is studied for: (1) the Escherichia coli lactose operator-repressor complex, (2) the complex between DNA bearing an analogue of an abasic site and the repair protein Fpg of Lactococcus lactis. Experimental patterns of DNA damages are presented and compared to predicted damage distribution obtained using an improved version of the stochastic model RADACK. The same method is used for predicting the location of damages on the proteins. At doses lower than a threshold that depends on the system, proteins protect their specific binding site on DNA while at high doses, the studied complexes are disrupted mainly through protein damage. The loss of binding ability is the functional consequence of the amino-acids modification by OH· radicals. Many of the most probably damaged amino acids are essential for the DNA-protein interaction and within a complex are protected by DNA

A mass spectrometry method for sensitive, specific and simultaneous detection of bovine blood meal, blood products and milk products in compound feed

Feed sustainability is one of the biggest challenges for the next few years. Solutions have to be found that take feed quality and safety into account. Animal by-products are one valuable source of proteins. However, since the bovine spongiform encephalopathy (BSE) crisis, their use has been strictly regulated. The objective of this study was to propose a routine, sensitive and specific method using ultra-high performance liquid chromatography coupled to tandem mass spectrometry for the detection of blood-derived products and milk powder in feed. Contaminated aquafeeds were analysed in order to evaluate the sensitivity and specificity of the method. This new method meets both selectivity and sensitivity (0.1% (w/w)) requirements imposed by the European Commission for animal proteins detection methods. It offers an innovative and complementary solution for the simultaneously identification of authorised and unauthorised animal by-products such as processed animal proteins (PAPs)