In vitro determination of the allergenic potential of egg white in processed meat.

Hen's egg white has been reported as a causative agent of allergic reactions, with ovalbumin, conalbumin, ovomucoid, and lysozyme being the major allergens. However, little is known about the effects of processing with heat and high pressure on the allergenicity of egg white proteins as ingredients in meat. For this purpose, the allergenic characteristics of such treated preparations were studied. The IgE-binding capacity was analyzed by EAST inhibition in raw and processed meat preparations using sera from patients with hen's egg specific IgE. Increasing heat treatment as well as the application of high pressure decreased IgE binding, which is a measure of allergenic potential. The combined application of heat (70°C) and high pressure had synergistic effects in reducing the allergenic potential nearly twice as the sum of the single treatments conducted separately.

Characterization, antigenicity and detection of fish gelatine and isinglass used as processing aids in wines.

Fish gelatine (FG) and isinglass (IG) are widely used in the pharmaceutical industry and as ingredients or processing aids in food production. Both products are the focus of interest since several countries, particularly the member states of the EU and Japan, USA, Australia and New Zealand, have introduced special labelling regulations for allergenic foodstuffs, such as fish and products thereof. Thus, there is a demand for a reliable and sensitive method for the detection of FG and IG in foodstuffs. In this study, the characterization of various FGs and IGs, polyclonal antibodies raised against fish collagen and the development of a sensitive indirect ELISA for the detection of FG and IG is described. The ELISA method detected < or =0.11 microg ml(-1) from all FGs and IGs tested. The indirect ELISA was applied to various experimental wines where FG and IG had been used as processing aids and to several commercial wines. No residues of FG and IG were detected in the experimental wines additionally treated with bentonite, a strong adsorbent for proteins, and successive filtration. Additionally, no residues were found in the commercial wines. However, amounts of up to 0.33 microg ml(-1) were found in some experimental wines not treated with bentonite and successive filtration. Therefore, wines may contain traces of FG and IG that were used as processing aids during wine production. However, treatment with bentonite in combination with additional filtration had a clear impact on these residues.

Competitive indirect ELISA for the determination of parvalbumins from various fish species in food grade fish gelatins and isinglass with PARV-19 anti-parvalbumin antibodies.

Parvalbumins are well-known as major fish allergens. However, no quantitative analytical method is currently available for the determination of parvalbumins from different fish species. The aim of this study was the isolation of the various parvalbumins by the application of gel chromatography and dialysis and the development and validation of a competitive indirect ELISA for the determination of parvalbumins from various fish species. This ELISA method was applied to several fish gelatins and isinglass samples used in food production. The competitive ELISA was capable of detecting all tested parvalbumins within a range of 0.1-0.5 mg/L. No parvalbumin was detected in any of the investigated fish gelatins or in a fish skin used as raw material for fish gelatin production. Contrarily, isinglass was found to contain parvalbumin amounts of up to 414.7 +/- 30.6 mg/kg.

Lysozyme in wine: A risk evaluation for consumers allergic to hen's egg.

Lysozyme used in wine production could present a risk for consumers allergic to hen's egg. Thus, precautionary labeling of lysozyme on wines has been adopted within the European Community by updating Annex IIIa by Directive 2007/68/EC on November 27, 2007. Since no scientific data is known about the actual amounts and risks of lysozyme in wines, various in vitro efforts and skin prick tests were applied in this study to evaluate the presence of lysozyme in wines and the reactivity of those residues in allergic individuals and to fulfill the claim of updating Annex IIIa announced in Directive 2003/89/EC. Depending on the wine's color (red or white wine) and fining with bentonite, which is known as an important step to remove unstable proteins mainly from white wines, diverse results were obtained concerning the amounts of lysozyme in finished wines and their in vitro and in vivo reactivity in humans allergic to hen's egg.

Aspects of food processing and its effect on allergen structure.

The article summarizes current physical and chemical methods in food processing as storage, preparation, separation, isolation or purification and thermal application on the one hand as well as enzymatic treatment on the other and their impact on the properties of food proteins. Novel methods of food processing like high pressure, electric field application or irradiation and their impact on food allergens are presented. The EU project REDALL (Reduced Allergenicity of Processed Foods, Containing Animal Allergens: QLK1-CT-2002-02687) showed that by a combination of enzyme and heat treatment the allergic potential of hen's egg decreased about 100 fold. Clinical reactions do not appear anymore. An AiF-FV 12024 N project worked with fruits like mango, lychee and apple. Processed mango and lychee had no change in allergenic potential during heating while e. g. canning. Apple almost lost its allergenic potential after pasteurization in juice production.

In vitro determination of the allergenic potential of technologically altered hen's egg.

Hen's egg allergy represents one of the most common and severe IgE-mediated reactions to food in infants and young children. It persists, however, in many cases also lifelong. Therefore, the aim of this study was the detailed analysis of a technological process used to reduce the allergenic potential of hen's egg. The investigation focused on the pasteurized egg as starting material, intermediate, and final products of a nine-step manufacturing process performed for use of eggs in convenience products appropriate for allergic individuals. The steps consisted of a combination of various heat treatments and enzymatic hydrolyses. The alterations were controlled by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, enzyme allergosorbent test (EAST) inhibition, and mass spectrometry. Thereby it could be demonstrated that the allergenic potential of the raw material was reduced from step to step, and despite the known stability against heat and proteolysis of certain egg proteins, the total allergenic potential was finally below 1/100 that of the starting material without a significant change in texture and flavor as evaluated in various products.

Investigation of the allergenic potential of wines fined with various proteinogenic fining agents by ELISA.

Hidden allergens are a common problem in food safety that has been known for many years. This is why the European Parliament adopted Directive 2003/89/EC amending 2000/13/EC. In addition to specific ingredients, Directive 2003/89/EC also requests the declaration of specific products that were used in the production and could be a risk for allergic individuals. This also includes the declaration of fining agents and lysozyme used in wines. In fact, it could be assumed that fining agents would be almost completely removed during the manufacturing process; however, until now there has been no necessity to analyze wine for these fining agents. By applying enzyme-linked immunosorbent assay (ELISA), residuals of fining agent proteins and the stabilizer lysozyme were investigated in various German wines. The results showed no detectable amounts of fining agents in wines, except for dried egg white and lysozyme, both derived from hen's egg white. For those products, adverse reactions against treated wines could not be excluded.

Effect of technological processing on the allergenicity of mangoes (Mangifera indica L.).

In parallel with the rising popularity of exotic fruits in Europe, allergy against mango is of increasing importance. Because mangoes are also consumed as processed products such as chutneys or beverages, the influences of different process conditions on their allergenicity were investigated. Mango purees and nectars were manufactured at small pilot-plant scale, and the allergenic potencies of the resulting intermediate and final products were determined by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting and inhibitive enzyme allergosorbent tests (EAST-inhibition), using a pool serum of 9 individuals with manifest mango allergy. The mango allergens were shown to be very stable during technological processing. Irrespective of enzymatic matrix decomposition, mechanical tissue disintegration and heating during peeling, mash treatment, and pasteurization, significant loss of allergenicity could not be observed in the extracts of mango purees and nectars derived thereof. These results were confirmed by analogous investigation of commercial mango drinks and nectars. Hence, conventional mango processing into pulp-containing products typical for this species obviously does not allow complete elimination of the allergenic potency.

Stability of bovine allergens during food processing.

OBJECTIVE: The primary objective of this review was to summarize reported findings about the influence of various food manufacturing processes on the potential alteration of bovine allergens in cow's milk, beef, and related food products. DATA SOURCES: This review was based on literature research in two German databases. STUDY SELECTION: The expert opinion of the authors was used to select the relevant data for the review. RESULTS: Changes in allergenic activity during food processing are attributable to inactivation or destruction of epitope structures, formation of new epitopes, or improved access of previously hidden epitopes. The allergenic potency of food could be altered by several food manufacturing procedures--such as mechanical, purification, thermal, biochemical, and chemical processes. The main processing steps studied by investigators were heating (dry heating, boiling, or cooking) and enzymatic digestion. A review of the available literature on the alteration of bovine allergens in cow's milk, meat, and related food products revealed reduction (but not elimination) of allergenicity by heating of cow's milk for 10 minutes. Although homogenization did not change the allergenic potency of cow's milk, it decreased the allergenicity of beef, as did freeze-drying. Digestion studies showed varied results. CONCLUSIONS: The allergenicity of some food products decreased during certain processing steps, but the results of other investigations differed. Therefore, more systematic research on the influence of food processing on allergenicity should be undertaken.