Elke Anklam

Methods for allergen analysis in food: a review

Food allergies represent an important health problem in industrialized countries. Undeclared allergens as contaminants in food products pose a major risk for sensitized persons. A proposal to amend the European Food Labelling Directive requires that all ingredients intentionally added to food products will have to be included on the label. Reliable detection and quantification methods for food allergens are necessary to ensure compliance with food labelling and to improve consumer protection. Methods available so far are based on protein or DNA detection. This review presents an up-to-date picture of the characteristics of the major food allergens and collects published methods for the determination of food allergens or the presence of potentially allergenic constituents in food products. A summary of the current availability of commercial allergen detection kits is given. One part of the paper describes various methods that have been generally employed in the detection of allergens in food; their advantages and drawbacks are discussed in brief. The main part of this review, however, focuses on specific food allergens and appropriate methods for their detection in food products. Special emphasis is given to allergenic foods explicitly mentioned in the Amendment to the European Food Labelling Directive that pose a potential risk for allergic individuals, namely celery, cereals containing gluten (including wheat, rye and barley) crustaceans, eggs, fish, peanuts, soybeans, milk and dairy products, mustard, tree-nuts, sesame seeds, and sulphite at concentrations of at least 10u2009mgu2009kg−1. Sulphites, however, are not discussed.

Peanut and hazelnut traces in cookies and chocolates: Relationship between analytical results and declaration of food allergens on product labels

Accidental exposure to hazelnut or peanut constitutes a real threat to the health of allergic consumers. Correct information regarding food product ingredients is of paramount importance for the consumer, thereby reducing exposure to food allergens. In this study, 569 cookies and chocolates on the European market were purchased. All products were analysed to determine peanut and hazelnut content, allowing a comparison of the analytical results with information provided on the product label. Compared to cookies, chocolates are more likely to contain undeclared allergens, while, in both food categories, hazelnut traces were detected at higher frequencies than peanut. The presence of a precautionary label was found to be related to a higher frequency of positive test results. The majority of chocolates carrying a precautionary label tested positive for hazelnut, whereas peanut traces were not be detected in 75% of the cookies carrying a precautionary label.

Inter-laboratory validation study of five commercial ELISA test kits for the determination of peanut proteins in biscuits and dark chocolate

The results of an inter-laboratory study with five commercially available peanut ELISA test kits to detect and quantify peanut residues in two food matrices (biscuit and dark chocolate) at four different concentrations (0–10u2009mg peanutu2009kg−1 matrix corresponding to about 0–2.5u2009mg peanut proteinu2009kg−1 matrix) are reported. In general the five ELISA test kits evaluated could detect peanut protein in the two food matrices. In three cases, the study challenged the test kits beyond their intended use for quantification below the manufacturers’ defined cut-off limits. Generally, all five ELISA test kits performed well in the concentration range 5–10u2009mgu2009kg−1 rather than in the low concentration range (2.0 or 2.5u2009mgu2009kg−1). The variation in the found recoveries of peanut between the different test kits had a spread of 44–191% across all concentrations. The quantification characteristics between test kits differed significantly at the very low mgu2009kg−1 level. Two test kits performed well even at concentrations below 5u2009mgu2009kg−1 with reproducibilities of 27–36% for biscuits and 45–57% for chocolate.

Acrylamide in coffee: review of progress in analysis, formation and level reduction.

This paper summarizes the progress made in understanding the formation of acrylamide in coffee, as well as potential reduction strategies, as presented during the joint CIAA/EC workshop on acrylamide, held in Brussels in March 2006. Currently, there are no concrete measures to reduce acrylamide concentrations in roast and ground coffee without appreciably changing the organoleptic properties of the product. Certain approaches, such as steam roasting, have been tried on a laboratory scale, albeit without affording a significant reduction. More work on the mechanisms governing the “loss” of acrylamide during storage of roast and ground coffee is warranted, and studies in this direction have been initiated. Finally, risk/benefit analysis must be addressed in a complex food such as coffee, known to harbour numerous health beneficial/chemoprotective compounds with antioxidant and antimutagenic properties.

Monitoring of bisphenol-A-diglycidyl-ether (BADGE) in canned fish in oil.

A survey at the European levels was initiated on the quantification of bisphenol-A-diglycidyl-ether (BADGE) in canned fish in oil in order to assess the exposure of BADGE. A total of 382 canned fish sample were collected from all 15 Member States and Switzerland and analysed for BADGE in fish. The fish was extracted first with hexane and reextracted with acetonitrile, followed by a membrane filtration and reverse phase HPLC analysis with fluorescence detection. The analysis of the fish showed that about 3% of the samples contained BADGE at a level above 1 mg/kg. The samples exceeding the limit by a larger margin were mostly from anchovy cans and cans manufactured in 1991-1995.

European Union database of acrylamide levels in food: Update and critical review of data collection

The European Commissions Directorate General Joint Research Centre has been collecting data produced by European Union Member States on the acrylamide content of food since 2003. More than 9000 individual data points have been received from official food control laboratories directly or via their Competent Authorities, and from the food industry. Before being entered into the database, the data were assessed for their reliability. This paper presents an update of the database as well as results of the evaluation of data for selected food commodities in order to establish a trend concerning the content of acrylamide in food. Experience gained with the data collection and data assessment are described and recommendations for future data collection initiatives given.

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil.

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.

Organic sulfuranyl radicals

Sulfuranyl radicals are intermediates in a variety of addition/elimination reactions of sulfides, disulfanes, sulfoxylates and S-neterocycles as well as in the reduction of triorgano- and heteroorgano sulfonium salts. Their lifetimes — depending on their substutution pattern — range from < 1 μs to being thermally stabee in solution at room temperature with no reduction in concentration over severll months.

2σ–1σ* Three-electron-bonded radical cations from alkylthio(halogeno)alkanes

Intramolecular sulphur–iodine (S∴I–)+ and sulphur–bromine (S∴Br–)+ three-electron-bonded radical cations have been observed during the oxidation of various iodo-and bromo-alkylthioalkanes by ·OH radicals. For the bromo compounds, in addition, intermolecular (S∴S)+ radical cations are stabilized at high solute concentrations. Oxidation of alkylthio (chloro) alkanes leads only to the dimer sulphur-sulphur three-electron-bonded radical cations. All these radical cations exhibit optical absorptions in the visible and near u.v. with extinction coefficients in the order of 4 000–8 000 mol–1 dm3 cm–1. In general, increasing the chain length between the sulphur and the halogen atoms, and increasing the electron release by the sulphur substituent, results in a red shift of the λmax. value and a decrease in radical cation yields. In aqueous solutions most of the three-electron-bonded species decay by first-order kinetics with t1/2 up to 110 µs.

Estimation of intake of bisphenol-A-diglycidyl-ether (BADGE) from canned fish consumption in Europe and migration survey

The exposure to bisphenol-A-diglycidyl-ether (BADGE) from canned fish in oil was assessed from consumption data collected for each Member State of the European Union and Switzerland, and migration data from a European survey on 382 samples. Trade figures were used when no consumption data were available. The average consumption of canned fish in Europe was 2.3 kg per person per year, with values ranging from 0.2 kg per person per year in the United Kingdom to 5.1 kg per person per year in Denmark. The exposure to BADGE was calculated as microgram per person per day. The data indicated that exposure to BADGE was in the range below 4 mg per person per year, i.e. 9 micrograms per person per day, hence a fairly low exposure in part due to the fact that canned fish is a relatively minor dietary item. An approximation assuming the general figure of a 60 kg adult, would thus be 0.15 microgram/kg body weight per day. This is a fairly limited exposure considering the provisional limit in food had been set a 1 mg/kg and assumed 1 kg of food ingested. In countries for which increased exposure was found, the reason was mainly caused by one individual sample exhibiting a high concentration rather than a larger number of samples with mildly elevated concentrations.