Major Food Allergens Research Articles

Low allergen content of commercial baby foods.

Introduction of allergenic solid foods, especially peanut and hen's egg reduces the risk of food allergy development in early childhood. Ideally, parents will offer their infants home-prepared foods; however, many rely on the availability of convenient ready to purchase infant foods. This audit aimed to assess the major food allergen content of commercial infant foods. Infant foods available for sale in 2019 in Australia were the focus of this audit. The major food allergens investigated were peanut, tree nuts, hen's egg, cows milk, wheat, fish, shellfish, soy, sesame and lupin. Websites of infant food manufacturers and major supermarkets were used to identify ingredient lists of infant foods available for purchase. Where ingredients listings were unavailable this information was sourced directly from the product labels in the supermarket. Fourteen companies were identified, manufacturing over 251 foods specifically for the infants aged less than 1 year of age. Although there were many choices available containing wheat (27 products) and cows milk proteins (73 products), none contained peanut, tree nuts, sesame, shellfish or lupin. Despite infant feeding advice encouraging early introduction to food allergens, of 251 commercial baby foods surveyed only 1% contained egg and none contained peanut, the most common food allergies in young Australian infants. This low food allergen content may be disadvantageous for infants fed mostly commercial infant foods as they are unlikely to be exposed to sufficient amounts of the major food allergens on a regular basis during infancy.

Effects of Maillard reaction on structural modification and potential allergenicity of peanut 7S globulin (Ara h 1).

Ara h 1 is a major food allergen in peanuts. Recently, many studies have revealed that the Maillard reaction (MR) affects the allergenicity of food proteins. To investigate the influence of the MR on the allergenicity of Ara h 1, R-Ara h 1 was processed with glucose in dry heating conditions for different periods. The extent of the MR was assessed by four methods. The changes in secondary and tertiary structures were characterized through spectroscopy assays. Advanced glycation end products (AGE) structures were identified by protein sample dry heating for 60 min, indicating the formation of AGE-Ara h 1. Simulated gastric fluid (SGF) digestion analysis showed that AGE-Ara h 1 has higher resistance to peptic digestion than R-Ara h 1. The BALB/c mouse model was also utilized to explore the effect of the MR on the allergenicity of Ara h 1, and the results showed that the Th2-type cytokines, antibodies, and histamine content increased, and there was a greater degree of degranulation of rat basophilic leukemia (RBL) cells in the AGE-Ara h 1 group compared with the R-Ara h 1 group. During the process of dry heating, proteins participated in the MR with changes in secondary and tertiary structures. The condition applying a temperature of 100 °C for 60 min caused the formation of AGE-Ara h 1. Simulated gastric fluid digestion analysis showed that AGE-Ara h 1 had a greater resistance to peptic digestion than R-Ara h 1. The BALB/c mouse model showed that AGE-Ara h 1 had more allergenicity, indicating that the MR could enhance the allergenicity of Ara h 1. © 2020 Society of Chemical Industry.

WHEAT AND PEANUT FOOD ALLERGY IN MUGWORT (ARTEMESIA VULGARIS) SENSITIZED PATIENTS: A CASE SERIES OF FOUR CASES

Non-specific lipid transfer proteins (LTPs) are the major food allergens in mugwort-Pollen Food Syndrome and are associated with systemic allergic reactions. We evaluated the relationship between mugwort pollen with peanut and wheat. The diagnosis was based on a convincing history of an allergic reaction after their food consumption and positive skin prick test with elevated food-specific immunoglobulin E (IgE) by Immunocap. We speculate that the causative allergenic protein Art V3 nsLTP in artemisia, Arh 9 nsLTP in peanut, and Tria 14 nsLTP in wheat are the major allergenic epitopes which are thermostable and resistant to peptic digestion, causing for systemic reaction in our cases.

Insight into the Mechanism of Reduced IgG/IgE Binding Capacity in Ovalbumin as Induced by Glycation with Monose Epimers through Liquid Chromatography and High-Resolution Mass Spectrometry.

Ovalbumin (OVA) is one of the major food allergens in hen eggs. In this work, it was demonstrated that glycation with d-glucose and its epimers, including d-mannose, d-allose, d-galactose, and l-idose, could effectively attenuate the IgG/IgE binding of OVA, which was attributed to the covalent masking by sugars and to its structural changes. The glycation sites were determined, and their average degree of substitution was found using liquid chromatography coupled with high-resolution mass spectrometry. Fluctuations in OVA conformation were monitored by conventional spectrometry. Compared to those of OVA-Man and OVA-Glu, OVA-All, OVA-Gal, and OVA-Ido showed a higher glycation extent, and the alterations on their steric layouts were more drastic, suggesting that the configuration of hydroxyl groups at positions C-3, C-4, and C-5 in sugars might be important for the glycation reactivity; as such, their capabilities in binding with IgG/IgE decreased more significantly. Attempts were made to provide valuable information for in-depth understanding of the differences in biochemical functionality among epimeric sugars. These insights would be helpful for designing sweetened food products with a desirable level of safety.

Milk Allergen Detection: Sensitive Label-Free Voltammetric Immunosensor Based on Electropolymerization

We present in this work, first time in literature, a voltammetric label-free biosensor for detection of alpha lactalbumin (α-LB) in meal samples. Food allergy concern necessitates strict regulations in food labelling and innovative monitoring strategies for prevention of sepsis-related death. As major food allergens, dietary samples often contain whey proteins, including α-LB as one of the key allergenic. Available detection methods for α-LB are based on successive labelling steps and hence have long assay times with limited sensitivity. The new detection method presented here is based on capturing of α-LB via entrapped α-LB antibody (α-LB-Ab) through electropolymerization of polypyrrole (PPy) and then measuring the conductivity decrease by differential pulse voltammetry (DPV). This new label-free voltammetric biosensor for α-LB exhibits the best limit of detection (0.19 fg/mL) published so far in literature, with high selectivity and capability to quantify α-LB in real milk samples too.

Subpixel detection of peanut in wheat flour using a matched subspace detector algorithm and near-infrared hyperspectral imaging

The detection of adulterations in food powder products represents a high interest especially when it concerns the health of the consumers. The food industry is concerned by peanut adulteration since it is a major food allergen often used in transformed food products. Near-infrared hyperspectral imaging is an emerging technology for food inspection. It was used in this work to detect peanut flour adulteration in wheat flour. The detection of peanut particles was challenging for two reasons: the particle size is smaller than the pixel size leading to impure spectral profiles; peanut and wheat flour exhibit similar spectral signatures and variability. A Matched Subspace Detector (MSD) algorithm was designed to take these difficulties into account and detect peanut adulteration at the pixel scale using the associated spectrum. A set of simulated data was generated to overcome the lack of reference values at the pixel scale and to design appropriate MSD algorithms. The best designs were compared by estimating the detection sensitivity. Defatted peanut flour and wheat flour were mixed in eight different proportions (from 0.02% to 20%) to test the detection performances of the algorithm on real hyperspectral measurements. The number and positions of the detected pixels were investigated to show the relevancy of the results and validate the design of the MSD algorithm. The presented work proved that the use of hyperspectral imaging and a fine-tuned MSD algorithm enables to detect a global adulteration of 0.2% of peanut in wheat flour.

The separation and identification of the residual antigenic fragments in soy protein hydrolysates.

Soybean is one of the major food allergens. In this study, soy protein isolate was hydrolyzed by Neutrase and Flavourzyme. The hydrolysates were separated by ultrafiltration and ion-exchange chromatography. The antigenicity of proteins was determined by indirect competitive ELISA. The molecular weight distribution was characterized by SDS-PAGE. The amino acid sequence of chromatography fractions was analyzed by LC-MS. The results showed that proteins with >50kDa in hydrolysates had the highest antigenicity and were further separated into F1 -F5 fragments by ion-exchange chromatography. Fragment F4 , which was the most antigenic, was analyzed by LC-MS. The results of mass spectrometry showed that most of the peptides that contained antigen epitopes in chromatography fraction F4 belonged to glycinin subunits. The antigenicity of soy protein was reduced by enzymatic hydrolysis, but glycinin showed resistance to enzymatic hydrolysis. PRACTICAL APPLICATIONS: The identification of residual antigenicity in soy protein hydrolysates by LC-MS provides important information on the resistance mechanism of enzymatic hydrolysis of soybean protein allergens. In addition, the efficient separation of soy protein hydrolysates could be beneficial for developing low-allergenic soybean products.

Recent Surveys on Food Allergy Prevalence

Substantial numbers of children and adults report having immunoglobulin E–mediated food allergies. However, generating accurate food allergy prevalence data is difficult. Self-reported data can overestimate prevalence when compared with prevalence estimates established by more rigorous methods. As of 2004, in the United States, the Food Allergen Labeling and Consumer Protection Act mandated that the label should declare the source of the food if the product contains that food or a protein-containing ingredient from that food (not all proteins in a major food allergen cause allergic reactions) in the manner described by the law. The 8 major food allergens are milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans, commonly referred to as the “Big 8.” These 8 allergens are thought to account for 90% of the food allergy reactions. Recently published large surveys of Americans and Canadian adults and children provide considerable insight into the prevalence of allergy for the major allergens. These data indicate that there is a large variation in prevalence among the Big 8. The prevalence of soy beans allergy is lower than the prevalence reported for each of the other 7 major allergens, which has been used to argue that soy could be removed from the Big 8 without risking harm to the public. However, the momentum appears to be in favor of expanding the Big 8. The US Food and Drug Administration is evaluating classification of sesame seed as a major allergen; it is already classified as a major allergen in Canada, Australia, and Europe. Europe classifies 14 foods as major allergens. There may be some advantage to standardizing major allergen lists globally, although it may be equally important to acknowledge differences in priority allergens based on cultural and dietary preferences. It is incumbent upon health professionals to help their patients and clients identify foods to which they are allergic and aid in planning diets that are nutritionally adequate despite elimination of these foods.

A study on the effect of nutrient intake on the body mass index of mothers of children with food allergies.

No previous studies have reported the effect of the presence of children with food allergies (FAs) on the diet and body mass index (BMI) of mothers. Therefore, we conducted a dietary survey and considered nutrients that influenced BMI of mothers. Subjects included 554 mothers-305 mothers of children with FAs (FA mothers; aged 38.4 ± 5.1 years, FA group) and 249 mothers of children without FAs (non-FA mothers; aged 37.7 ± 5.5 years, NFA group). We extracted dietary patterns from dietary survey results and investigated the correlation between nutrient intake and BMI. We divided the FA group into two groups (one containing 181 mothers whose children were allergic to ≤ 1 of the three major allergenic foods-eggs, milk and wheat-and another containing 124 mothers whose children were allergic to ≥ 2 of these foods) and conducted a comparative analysis. BMI was significantly lower in the FA group than in the NFA group (20.7 vs. 21.4 kg/m2). There was a significant negative correlation between BMI and vegetable protein intake (β = -0.196, SE = 0.05). Vegetable protein intake was higher in the group that was allergic to ≥ 2 of the allergenic foods. BMI of FA mothers is affected by a diet that strictly follows their FA child's allergen-free state-a diet dominated by vegetable protein. These observations suggested that the degree to which an FA mother is affected depends on the number of the three major allergenic foods to which her FA child is allergic.

Enhancing online protein isolation as intact species from soy flour samples by actively modulated two-dimensional liquid chromatography (2D-LC)

In this study, an enhanced fully automated approach is described for the protein isolation from soy flour samples by two-dimensional liquid chromatography with active modulation interface. The use of two multi-port switching valves is proposed to on-line connect the first to the second dimension column, thus overcoming the problems associated with the re-mixing effects and incompatibility of eluent composition and pH. A 5-cm long C4 analytical column installed in the interface device allows to focus the proteins coming from the first column (size exclusion chromatography), before their selective elution in the second column (reversed-phase). A trap washing step was included in the total workflow, as a desalting step to remove buffer residues from the eluent of the first column and to enhance the chromatographic performances of the second column. The experimental conditions were optimized by analyses of mixed standard solutions of bovine serum albumin, glucose oxidase, immunoglobulin A, thyroglobulin and myoglobin. Then, the optimized 2D-LC method was applied to the protein analysis in extracts of soy flour, known worldwide as one of the major food allergen sources, with the final aim to recovery sufficient protein amounts for the molecular characterization and the assessment of the pattern of allergenic components.

Food allergy: Diagnosis and treatment.

Immunoglobulin E-mediated food reactions usually develop within minutes of food ingestion. Although most reactions are not life-threatening, fatalities do occur. Risk factors for fatal food-induced anaphylaxis include the presence of asthma (a risk factor for anaphylaxis in general), failure to use epinephrine autoinjectors promptly, a history of severe reactions, known food allergy, denial of symptoms, and adolescent and young adult age. The most commonly implicated foods are cow's milk, egg, peanut, soy, tree nuts, fish, shellfish, and wheat. Peanut, tree nuts, and seafood are the most common food allergens in adults, whereas cow's milk, peanut, egg, soy, and wheat are more common in children. The major food allergens are glycoproteins, which are generally water soluble and stable to the effects of heat, proteases, and acids. Recent studies showed that natural tolerance can be acquired at a later age than previously thought, even during adolescence. Allergies to peanut, tree nuts, and seafood are frequently life-long. Patients and their caregivers should be taught when and how to administer injectable epinephrine. In terms of primary prevention, there is evidence that early introduction, followed by ongoing regular consumption of peanut has a protective effect on the development of peanut allergy.

Yogurt-sourced probiotic bacteria alleviate shrimp tropomyosin-induced allergic mucosal disorders, potentially through microbiota and metabolism modifications

BackgroundShrimp tropomyosin (TM) is a major food allergen that may cause serious allergic responses, lactic acid-producing bacteria (LAPB) are believed to alleviate food allergy, but the mechanisms have not been fully clarified. The aim of this work is to investigate the mechanisms of LAPB in ameliorating food allergy-induced intestinal mucosal disorders and to investigate whether or not these disorders occur by the regulation of gut microbiota and metabolism. MethodsA TM allergy BALB/c mouse model was established, and two LAPB strains, Bifidobacterium longum (Bi) and Bacillus coagulans (Bc), were used for oral treatment in sensitized mice. The allergic mucosal disorders were assessed by histological analysis and ELISAs. Additionally, microbiota and metabolic modifications were determined by 16S rRNA gene amplicon sequencing and GC-TOF-MS, respectively. ResultsYSPB administration suppressed TM-induced intestinal mucosal disorders, restored allergenic Th2 cell over-polarization and dysbiosis, and regulated gut arginine and proline metabolism pathways. Statistical analysis suggested the metabolites aspartate and arginine, as well as several commensal flora groups, to be the critical mediators in the process. ConclusionsThese data demonstrated the correlation between allergic mucosal disorder, T cell subtype differentiation, gut microbiota composition and intestinal metabolism especially the arginine and proline metabolism pathways. We also revealed the significant effects of LAPB in ameliorating food allergy and maintaining the mucosal ecosystem. This study confirmed the efficiency of LAPB in relieving food allergy, provided Bi and Bc as the potential treatment approaches, and suggested amino acid metabolism pathways might be the novel targets for potential clinical applications.

Food processing and occupational respiratory allergy- An EAACI position paper.

Occupational exposure to foods is responsible for up to 25% of cases of occupational asthma and rhinitis. Animal and vegetable high-molecular-weight proteins present in aerosolized foods during food processing, additives, preservatives, antioxidants, and food contaminants are the main inhalant allergen sources. Most agents typically cause IgE-mediated allergic reactions, causing a distinct form of food allergy (Class 3 food allergy). The allergenicity of a food protein, allergen exposure levels, and atopy are important risk factors. Diagnosis relies on a thorough medical and occupational history, functional assessment, assessment of sensitization, including component-resolved diagnostics where appropriate, and in selected cases specific inhalation tests. Exposure assessment, including allergen determination, is a cornerstone for establishing preventive measures. Management includes allergen exposure avoidance or reduction (second best option), pharmacological treatment, assessment of impairment, and worker's compensation. Further studies are needed to identify and characterize major food allergens and define occupational exposure limits, evaluate the relative contribution of respiratory versus cutaneous sensitization to food antigens, evaluate the role of raw versus cooked food in influencing risk, and define the absolute or relative contraindication of patients with ingestion-related food allergy, pollinosis, or oral allergy syndrome continuing to work with exposure to aerosolized food allergens.

Food allergy test in chronic urticaria adult patients: A cross sectional study

Food allergy test in chronic urticaria adult patients: A cross sectional study - IJCED- Print ISSN No: - 2581-4710 Online ISSN No:- 2581-4729 Article DOI No:- 10.18231/j.ijced.2019.027, IP Indian Journal of Clinical and Experimental Dermatology-IP Indian J Clin Exp Dermatol

Structure Analysis of a Pathogenesis-Related 10 Protein from Gardenia jasminoides

The PR-10 proteins belongs to the huge family of pathogenesis related proteins ubiquitous in the plant kingdom, and it includes major food and tree pollen allergens, major latex proteins (MLPs) and cytokinin-specific binding proteins(CSBPs). In this work, a fruit cDNA library of Gardenia jasminoides was constructed, and the GjPR10 cDNA was isolated from the library by sequencing method. The GjPR10 cDNA contains a predicted 486 bp open reading frame, the putative protein contains 161 amino acids, and the protein has a calculated molecular mass 17.7kDa and a theoretical pI 6.25, these characters consistent with usual plant PR10 protein features. A bioinformatics analysis was conducted with previously characterized PR-10 proteins from other plant species. A three-dimensional model of GjPR10 was built. The bioinformatics analysis suggests that the GjPR10 present the conserved P-loop motif. The three-dimensional structure of GjPR10 has the significant common feature of PR10 proteins, it is composed of three alpha-helices and a seven-stranded antiparallel beta-sheet arranged to form a large internal hydrophobic cavity. The results suggest that GjPR10 is a typical PR10 protein, GjPR10 might be involved in plant defence response, developmental processes and in secondary metabolism.

Detection of Six Commercially Processed Soy Ingredients in an Incurred Food Matrix Using Parallel Reaction Monitoring

Soybeans are one of the major allergenic foods in many countries. Soybeans are commonly processed into different types of soy ingredients to achieve the desired properties. The processing, however, may affect the protein profiles and protein structure, thus affecting the detection of soy proteins. Mass spectrometry (MS) is a potential alternative to the traditional immunoassays for the detection of soy-derived ingredients in foods. This study aims to develop a liquid chromatography-tandem MS method that uniformly detects different types of soy-derived ingredients. Target peptides applicable to the detection of six commercial soy ingredients were identified based on the results of MS label-free quantification and a set of selection criteria. The results indicated that soy ingredient processing can result in different protein profiles. A total of six soy ingredients were then individually incurred into cookie matrices at different levels. Sample preparation methods were optimized, and a distinct improvement in peptide performance was observed after optimization. Cookies and dough incurred with different soy ingredients at 100 ppm total soy protein showed a similar level of peptide recovery (90% mean signal relative to unroasted soy flour), demonstrating the ability of the MS method to detect processed soy ingredients in a uniform manner.

Sensitivity analysis to derive a food consumption point estimate for deterministic food allergy risk assessment

One of the input parameters in food allergy risk assessment is the amount of a given food consumed at an eating occasion. There is no consensus on how to use food consumption data when assessing the risk from unintended allergen presence in food products. A sensitivity analysis was performed to establish the optimal food consumption estimate for a deterministic food allergy risk assessment. Exposure was calculated for consumption percentiles (50th percentile, P50 to maximum) using the iFAAM consumption database in conjunction with an allergen concentration range from 1 to 1000 ppm. The resulting allergen intakes were compared to the allergic population reference doses proposed by Taylor et al. (2014) for 10 major allergenic foods. Optimal consumption percentiles were defined as those which predicted an intake below the relevant reference dose and met the defined acceptable risk level confirmed by probabilistic risk assessments. Analysis showed that, for 99% of the food groups, the P50 consumption met our criteria, while the P75 did so for 100% of the food groups. We suggest that the P75 is the optimal point estimate for use in deterministic food allergy risk assessment. It meets the safety objective and is adequately conservative for a public health context.

IgE testing can predict food allergy status in patients with moderate to severe atopic dermatitis

BackgroundDiagnosing food allergy in patients with atopic dermatitis (AD) is complicated by their high rate of asymptomatic sensitization to foods, which can lead to misdiagnosis and unnecessary food avoidance. ObjectiveWe sought to determine whether food-specific (sIgE) or component immunoglobulin (Ig) E levels could predict allergic status in patients with moderate to severe AD and elevated total IgE. MethodsSeventy-eight children (median age, 10.7 years) with moderate to severe AD were assessed for a history of clinical reactivity to milk, egg, peanut, wheat, and soy. The IgE levels for each food and its components were determined by ImmunoCAP. The level and pattern of IgE reactivity to each food and its components, and their ratio to total IgE, were compared between subjects who were allergic and tolerant to each food. ResultsNinety-one percent of subjects were sensitized, and 51% reported allergic reactivity to at least 1 of the 5 most common food allergens. Allergy to milk, egg, and peanut were most common, and IgE levels to each of these foods were significantly higher in the allergic group. Component IgEs most associated with milk, egg, and peanut allergy were Bos d8, Gal d1, and Ara h2, respectively. The ratio of sIgE to total IgE offered no advantage to sIgE alone in predicting allergy. ConclusionSpecific IgE levels and the pattern of IgE reactivity to food components can distinguish AD subjects allergic vs tolerant to the major food allergens and may therefore be helpful in guiding the clinical management of these patients.

Mugwort Pollen-Related Food Allergy: Lipid Transfer Protein Sensitization and Correlation With the Severity of Allergic Reactions in a Chinese Population.

PurposeLittle is known about the importance of lipid transfer protein (LTP) sensitization in China. In this study, we investigated the relationship between LTP sensitization and the severity of clinical symptoms in a population of patients with mugwort pollen-related food allergy.MethodsFood-induced symptoms were evaluated in 148 patients with mugwort pollen allergy by a standardized questionnaire. Specific immunoglobulin E (IgE) to Art v 1, Art v 3, Pru p 3, Ara h 9 and Cor a 8 were quantified by ImmunoCAP. Immunoblotting of peach extracts were performed with sera from peach-allergic patients.ResultsIn total, 72% (107/148) of the study population experienced food allergy. Forty-eight percent (51/107) of patients with mugwort pollen-related food allergy experienced at least 1 episode of food-induced anaphylaxis. Food allergy correlated with IgE reactivity to Art v 3, but not to Art v 1. Sensitization to Pru p 3, Ara h 9 or Cor a 8 was prevalent (80%, 69 or 63%, respectively) among individuals with food allergy. Food allergic patients with systemic reactions (SR) had higher values for Pru p 3, Ara h 9 and Cor a 8 than patients with oral allergy syndrome (OAS). Furthermore, the strong IgE reactivity detected in immunoblots of peach extracts indicated that Pru p 3 was the major allergen and was more prevalent in patients with SR than in patients with OAS (100% vs. 55%).ConclusionsLTPs are major food allergens for mugwort pollen-related food allergy in China, and may contribute to SR.

Percutaneous Sensitization to Soybean Proteins Is Attenuated by Oral Tolerance.

Oral tolerance prevents allergic responses, but cutaneous exposure to food allergens predisposes individuals to food allergies. Soybean, a major allergenic food, is also an ingredient in various cosmetic products. However, it remains to be determined whether oral tolerance prevents percutaneous sensitization to soybean proteins in humans or animal models. In this study, BALB/c mice were divided into three groups; the SS group fed a soybean-containing diet, and the CS and control (C) groups fed a soybean-free diet. After being dorsally shaved, the CS and SS groups were epicutaneously exposed to a soybean extract while the control group was exposed to only the carrier. Specific IgE and IgG1 immunoglobulins secreted in response to the soybean proteins were measured using enzyme-linked immunosorbent assays. Exposure to the soybean extract elicited the secretion of IgE and IgG1 specific for Gly m 5 and Gly m 6, and trypsin inhibitor. Oral soybean consumption attenuated the secretion of all the soybean-specific IgEs and IgG1s, suggesting that percutaneous sensitization to soybean proteins is attenuated by oral tolerance.