Detection of walnut residues in foods using an enzyme-linked immunosorbent assay.

Tree nuts, including walnuts, can be responsible for allergic reactions. Food manufacturers have the responsibility to declare the presence of walnuts on packaged foods even when trace residues may be present from the use of shared equipment or the adventitious contamination of ingredients. The aim of this study was to develop a rapid, sensitive, and specific enzyme-linked immunosorbent assay (ELISA) method for the detection of walnut protein residues.

Consumer attitudes and risks associated with packaged foods having advisory labeling regarding the presence of peanuts.

Background: Foods with advisory labeling (eg, "may contain") are increasingly prevalent. Consumers with food allergies might ignore advisory labeling advice.

Objective: We sought to determine whether consumers with food allergy heeded advisory labels and whether products with advisory labels contained detectable peanut allergen.

Determination of no-observed-adverse-effect levels and eliciting doses in a representative group of peanut-sensitized children.

Background: Current labeling practices for allergenic foods like peanut can be inadequate. For future regulatory and industry guidelines, information on no-observed-adverse-effect levels (NOAELs) and eliciting doses (EDs) for allergenic foods is necessary.

Objective: To determine NOAEL and ED in a representative group of peanut-sensitized children, relate these data to history and sensitization, and evaluate the outcome of dietary management.

IgE binding to pepsin-digested food extracts.

Background: Pepsin resistance of allergens like lipid transfer protein and 2S albumin has been suggested as explanation for the severity of symptoms often induced by these allergens. Component-resolved diagnosis with purified labile and stable allergens has therefore been proposed to better characterize the risk involved in a positive in vitro IgE test. However, for many foods, purified allergens are not (yet) available.

In silico methods for evaluating human allergenicity to novel proteins: International Bioinformatics Workshop Meeting Report, 23-24 February 2005.

The ILSI Health and Environmental Sciences Institute (HESI) hosted an expert workshop 22-24 February 2005 in Mallorca, Spain, to review the state-of-the-science for conducting a sequence homology/bioinformatics evaluation in the context of a comprehensive allergenicity assessment for novel proteins, to obtain consensus on the value and role of bioinformatics in evaluating novel proteins, and to discuss the utility and methods of allergen-specific IgE testing in the diagnosis of food allergy. The workshop participants included over forty international experts from academia, industry, and government. The workshop was hosted by the HESI Protein Allergenicity Technical committee, which has established a long-term program whose mission is to advance the scientific understanding of the relevant parameters for characterizing the allergenic potential of novel proteins.

Proteolytic processing of the peanut allergen Ara h 3.

The allergen Ara h 3 has been purified recently from peanuts. In contrast to recombinant Ara h 3, a 60 kDa single-chain polypeptide, the allergen isolated from its native source is extensively proteolytically processed. The characteristic proteolytic processing for 11S plant storage proteins of the glycinin family is observed for Ara h 3 yielding an acidic and a basic subunit, bound by a disulfide bridge.

Assessing genetically modified crops to minimize the risk of increased food allergy: a review.

The first genetically modified (GM) crops approved for food use (tomato and soybean) were evaluated for safety by the United States Food and Drug Administration prior to commercial production. Among other factors, those products and all additional GM crops that have been grown commercially have been evaluated for potential increases in allergenic properties using methods that are consistent with the current understanding of food allergens and knowledge regarding the prediction of allergenic activity. Although there have been refinements, the key aspects of the evaluation have not changed.

A novel approach for the detection of potentially hazardous pepsin stable hazelnut proteins as contaminants in chocolate-based food.

Contamination of food products with pepsin resistant allergens is generally believed to be a serious threat to patients with severe food allergy. A sandwich type enzyme-linked immunosorbent assay (ELISA) was developed to measure pepsin resistant hazelnut protein in food products. Capturing and detecting rabbit antibodies were raised against pepsin-digested hazelnut and untreated hazelnut protein, respectively.

Detection of soy proteins in processed foods: literature overview and new experimental work.

Several tests for the detection of soy proteins in foods have been described in the literature, and some are commercially available. This article gives an overview of these methods and discusses the advantages and disadvantages of each individual method. Based on the conclusions of this inventory, an experimental approach was designed to improve the sensitivity of measuring soy protein in processed foods.

Reversible denaturation of Brazil nut 2S albumin (Ber e1) and implication of structural destabilization on digestion by pepsin.

The high resistance of Brazil nut 2S albumin, previously identified as an allergen, against proteolysis by pepsin was examined in this work. Although the denaturation temperature of this protein exceeds the 110 degrees C at neutral pH, at low pH a fully reversible thermal denaturation was observed at approximately 82 degrees C. The poor digestibility of the protein by pepsin illustrates the tight globular packing.

Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy.

Background: We recently described patients with soybean allergy mainly mediated by cross-reactivity to birch pollen allergens. A majority of those patients were reported to have peanut allergy.

Objective: We sought to study the occurrence of peanut allergy in patients allergic to birch pollen and characterized the Bet v 1-homologous peanut allergen Ara h 8.

A randomized, double-blinded, placebo-controlled oral challenge study to evaluate the allergenicity of commercial, food-grade fish gelatin.

Background: Recent interest in the labeling of foods and food proteins derived from allergenic sources necessitates determination of the potential allergenicity of such food ingredients. Fish gelatin is extracted from the skin of fish species known to elicit allergic reactions in sensitized individuals.

Objective: To determine the allergenicity of fish gelatin by double-blinded, placebo-controlled food challenges (DBPCFC) in clinically fish-allergic individuals.

Validated sandwich enzyme-linked immunosorbent assay for casein and its application to retail and milk-allergic complaint foods.

Cows' milk is a commonly allergenic food. Cross-contamination of milk proteins into nondairy, kosher-pareve foods prepared on shared processing equipment can cause severe, life-threatening reactions in milk-allergic individuals. A sandwich-type enzyme-linked immunosorbent assay (ELISA; 96-well plate format) was developed for the detection of undeclared casein in foods.

In vitro and in vivo characterization of hazelnut skin prick test extracts.

Rationale: Hazelnut allergy ranks among the most frequently observed food allergies. Clinical symptoms range from the oral allergy syndrome to life threatening anaphylaxis. Diagnosis of hazelnut allergy partially relies on in vivo testing by means of skin prick testing (SPT).

Food allergy and the food industry.

Although most food-allergic reactions occur after ingestion of nonpackaged food products, the food industry has been subjected to increasing scrutiny of their allergen controls; the resulting impact on the industry has been remarkable. Undeclared food allergens have been responsible for many food product recalls during the past 13 years, and the food industry has made significant investment, effort, and improvements in allergen control during this time. Recently, tests for some allergenic foods have been commercialized, and proven useful to the industry in controlling allergens and helpful for regulatory agencies investigating food-allergic consumer complaints.

The distribution of individual threshold doses eliciting allergic reactions in a population with peanut allergy.

Background: Hidden peanut in consumer products can endanger patients with peanut allergy. Individual threshold doses for eliciting allergic reactions need to be elucidated to assess the risks for development of allergic reactions after accidental ingestion of peanut in a population with peanut allergy.

Objective: We sought to determine the distribution of individual threshold doses in a population with peanut allergy and to correlate these thresholds to the severity of peanut-induced symptoms.

Bioinformatic methods for allergenicity assessment using a comprehensive allergen database.

Background: A principal aim of the safety assessment of genetically modified crops is to prevent the introduction of known or clinically cross-reactive allergens. Current bioinformatic tools and a database of allergens and gliadins were tested for the ability to identify potential allergens by analyzing 6 Bacillus thuringiensis insecticidal proteins, 3 common non-allergenic food proteins and 50 randomly selected corn (Zea mays) proteins.

Methods: Protein sequences were compared to allergens using the FASTA algorithm and by searching for matches of 6, 7 or 8 contiguous identical amino acids.

Genetically engineered foods: implications for food allergy.

The products of agricultural biotechnology, including such common foods as corn and soybeans, are already reaching the consumer marketplace. Consumer exposure to such foods is already fairly significant, particularly in the USA. Thus far, no reports exist regarding allergic reactions to the crops that have been approved for introduction into the food supply.

How much food is too much? Threshold doses for allergenic foods.

This review summarizes recent findings and controversies in the area of threshold doses for allergenic foods. Over the years, there have been many clinical reports that ingestion of small amounts of food can elicit IgE-mediated allergic reactions. In exquisitely allergic individuals, the threshold dose for elicitation of such reactions is often considered to be zero.

Factors affecting the determination of threshold doses for allergenic foods: how much is too much?

Background: Ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies. The threshold dose for provocation of such reactions is often considered to be zero. However, because of various practical limitations in food production and processing, foods may occasionally contain trace residues of the offending food.

A Sandwich Enzyme-Linked Immunosorbent Assay (ELISA) for the Quantitation of Selected Peanut Proteins in Foods.

A sandwich-type, enzyme-linked immunosorbent assay (ELISA) was developed for the detection of selected peanut proteins in foods. Monoclonal antibodies against a series of allergenic peanut proteins were used as the capture antibody. Food sample extracts were then added, and polyclonal rabbit antibodies directed against roasted peanut proteins were employed as secondary antibodies.