Potential Food Allergens Research Articles

An approach to allergy risk assessments for e-liquid ingredients

Many flavours and fragrances are known allergens. Their selection and inclusion levels in e-liquids must therefore be guided by toxicological principles, taking into account the exposure pattern and inhalation route of exposure. For contact sensitisation, a general, agreed quantitative risk assessment approach to prevent dermal sensitisation exists. Here we propose exposure parameters and safety factors to apply this approach to e-liquid ingredients. Additionally, as a risk management approach for pre-sensitised individuals, we derive a threshold of 0.1% for indicating the presence of a contact sensitiser in e-liquid. Risk assessment for respiratory sensitisation is not well established. Occupational exposure limits that protect against respiratory allergy are generally very low. Cocoa shell extract is used as a case study to discuss the issues. A tolerable exposure level is derived and estimates of consumer exposure are presented, leading to the practical risk management approach of excluding respiratory sensitisers as e-liquid ingredients. Related to this, if natural extracts are used as flavourings in e-liquids, we recommend only protein-free versions are used. Additionally, we recommend the presence of any potential food allergens should be noted on the product information.

The role of dietary interventions in the prevention of IgE-mediated food allergy in children.

Over the last 30 years, the prevalence of food allergy has been on the rise and remains a disease that can have a significant impact on the quality of life of children and their families. There are several hypotheses that have been suggested to account for the increasing prevalence, but this review will focus on the impact that dietary factors have on food allergy development. In the past food allergy, prevalence has largely focused on allergen avoidance; however, there is increasing evidence from interventional studies that have shown that early introduction to potential food allergens may have a beneficial role in allergy prevention. This review aims to look at the evidence in support of early introduction of allergens into infant diets to prevent against the development of food allergy.

Timing of food introduction and atopy prevention

The apparent increase in atopic disease, particularly food allergy, over the past 2 decades has resulted in reconsideration of prevention strategies aimed at the infant’s diet. Early advice to have atopy-prone infants delay ingestion of potential food allergens, such as egg, cow’s milk, and peanut, was rescinded, as new evidence emerged that did not support these approaches. More recently, randomized controlled trials have provided data to support an opposite strategy, promoting early ingestion of allergens as a means of food allergy prevention. Specifically, new guidelines suggest early ingestion of peanut as a means to prevent peanut allergy. Additional dietary approaches regarding breastfeeding, early introduction of other types of food allergens, formula feeding, dietary nutrients, and probiotics are also under scrutiny as potential preventative strategies. This review focuses on the timing of food introduction as a preventative strategy for food allergy and also discusses other aspects of the infant diet that may provide opportunities for prevention of atopic disease.

IgE Cross-Reactivity Between Shellfish and Diverse Potential Food Insects

Is observed IgE cross-reactivity of insect and shellfish tropomyosins explained by sequence and/or structural characteristics and if so can we use this to predict likely reactivity? We analyzed cross-reactivity patterns of shellfish and seven insect species using sera from 14 shellfish allergic individuals using IgE immunoblotting. We obtained protein sequences either from public databases (where available) or from translation of novel insect tropomyosin genes cloned in our lab. Relevence of both existing and novel tropomyosin sequences was demonstrated by quantitative protein mass spectrometry. Distinct patterns of cross-reactivity were observed, with three edible insect species consistently displaying lower binding of IgE. This pattern was not due to overall sequence homology. These results will be discussed with reference to differences in localized protein sequence motifs and other phyisco-chemical protein properties. Edible insects vary in the capacity of major allergens to bind shrimp allergic IgE, and therefore potentially elicit allergic reactions. This information is essential for the successful risk assessment of edible insects as potential food allergens.

Crystal structure of cocosin, a potential food allergen from coconut (Cocos nucifera)

Crystal structure of cocosin, a potential food allergen from coconut (Cocos nucifera)

In vitro selection of DNA aptamers targeting β-lactoglobulin and their integration in graphene-based biosensor for the detection of milk allergen

Food allergy has increased rapidly in recent years affecting millions of people worldwide. With the increased consumption of packed food nowadays, a sensitive, accurate and rapid screening method for potential food allergens has become an urgent need in order to protect the sensitive consumers from life-threatening reactions. The current detection methods for food allergens are mostly based on immunoassays which are costly and times-consuming. In this work, we developed an aptamer/graphene-based electrochemical biosensor for on-step, sensitive and low cost detection of β-lactoglobulin (β-LG) milk protein, one of the most common food allergens specially in infants. The selection of DNA aptamers against the two β-LG variants A and B was successfully realised using systemic evolution of ligands by exponential enrichment (SELEX) method. Among the selected aptamers, BLG14 aptamer sequence has shown high affinity and specificity to both β-LG A and B with dissociation constants (Kds) of 82 and 80nM, respectively as calculated using fluorescence binding assays. The aptamer was then integrated in a voltammetric biosensor utilizing graphene-modified screen printed carbon electrodes. The binding is monitored by following the change in the square wave voltammetry (SWV) reduction peak signal of ferrocyanide/ferricyanide redox couple due to the removal of the negatively charged aptamers from the surface upon protein binding. This one-step "signal on" biosensor takes 20min for the sensitive and selective detection of β-LG without using any labelling or sophisticated designs. The method was also tested in spiked food sample extract achieving good recovery percentage. The integration of the novel aptamer in the graphene biosensor allows a promising way for cost-effective, rapid and sensitive on-site detection of milk allergen in food stuff.

Allergenic potential of food derived from genetically modified plants: current and challenges status

Allergenic potential of food derived from genetically modified plants: current and challenges status

Matrix-normalised real-time PCR approach to quantify soybean as a potential food allergen as affected by thermal processing.

The addition of soybean protein materials to meat products is a common practice in the food industry, being a potential hidden allergenic commodity. This study aimed at proposing a novel specific and highly sensitive real-time PCR system for the detection/quantification of soybean as an allergenic ingredient in processed meat products. The method achieved a limit of detection of 9.8pg of soybean DNA (8.6 copies), with adequate real-time PCR performance parameters, regardless of the soybean material (concentrate or isolate) and after thermal treatments. A normalised approach was also proposed in the range of 0.001-10% (w/w) of soybean material in pork meat, which was successfully validated and applied to processed meat products. Soybean was identified in more than 40% of tested samples of cooked ham and mortadella in the range of 0.1-4% (w/w), 3 samples not complying with labelling regulations as a result of undeclared soybean.

Respiratory allergy risk assessment for e-cigarette ingredients – Cocoa extract as a case study

Many flavours and fragrances are known allergens. Their selection and inclusion levels in e-liquids must therefore be guided by toxicological principles, taking into account the exposure pattern and inhalation route of exposure. For contact sensitisation, a general, agreed quantitative risk assessment approach to prevent dermal sensitisation exists. Here we propose exposure parameters and safety factors to apply this approach to e-liquid ingredients. Additionally, as a risk management approach for pre-sensitised individuals, we derive a threshold of 0.1% for indicating the presence of a contact sensitiser in e-liquid. Risk assessment for respiratory sensitisation is not well established. Occupational exposure limits that protect against respiratory allergy are generally very low. Cocoa shell extract is used as a case study to discuss the issues. A tolerable exposure level is derived and estimates of consumer exposure are presented, leading to the practical risk management approach of excluding respiratory sensitisers as e-liquid ingredients. Related to this, if natural extracts are used as flavourings in e-liquids, we recommend only protein-free versions are used. Additionally, we recommend the presence of any potential food allergens should be noted on the product information.

High pressure processing assisted enzymatic hydrolysis – An innovative approach for the reduction of soy immunoreactivity

Abstract Soybean (Glycine max (L.) MERR.) is recognized as a potent food allergen causing one of the most frequent food allergies worldwide. The effect of high pressure processing (HPP) prior to and during enzymatic hydrolysis using the enzyme preparation Flavourzyme® on the degree of hydrolysis (DH), molecular weight distribution (SDS-PAGE) and β-conglycinin (Gly m5) immunoreactivity of soy protein isolate (SPI) was studied. Enzymatic hydrolysis was carried out at atmospheric pressure (0.1 MPa) and HPP (100–600 MPa) at 50 °C for 15 min. Pressures higher than 300 MPa enhanced the degradation of Gly m5, which was confirmed by SDS-PAGE and LC-MS/MS analyses. The immunoreactivity of the samples was assessed by in vitro sandwich ELISA using mouse monoclonal anti-Gly m5 antibodies. Depending on the antibody tested, the residual immunoreactivity was completely inhibited or significantly impaired up to 99.5% applying HPP during hydrolysis at 400 and 500 MPa. By means of principal component analysis, the beany and green off-flavors characteristic for unprocessed SPI could be reduced by pressure enhanced hydrolysis at 400–500 MPa. The resulting hydrolysates possessed improved protein solubility, foaming activities and oil-binding capacities, which were improved by 45%, 66%, and 210%, respectively. HPP prior to and during enzymatic hydrolysis at 400–500 MPa constitutes an innovative approach for the production of low-allergen food ingredients that combine good taste and enhanced functional properties. Industrial relevance Food allergy has emerged in the last years as the incidence and prevalence are rising dramatically. Up to now, enzymatic hydrolysis is the only feasible method to mitigate soy allergy. However, the major drawback associated with enzymatic hydrolysis is the incomplete destruction of allergenic epitopes and the formation of a strong bitter taste. This research activity demonstrates that high pressure assisted enzymatic hydrolysis using the enzyme preparation Flavourzyme effectively reduces the immunoreactivity of soy proteins. Degree of hydrolysis analysis, SDS-PAGE, mass spectrometry as well as sandwich ELISA with mouse monoclonal anti-Gly m5 antibodies have been applied to analyze the destruction of allergenic proteins as well as to determine the residual immunoreactivity. This study provides preliminary evidence that this innovative combination process of high pressure and enzymatic hydrolysis has great potential to produce tasty low-allergen soy-based food ingredients with good physicochemical properties, i.e. protein solubility and foamability.

Genomics of Three New Bacteriophages Useful in the Biocontrol of Salmonella.

Non-typhoid Salmonella is the principal pathogen related to food-borne diseases throughout the world. Widespread antibiotic resistance has adversely affected human health and has encouraged the search for alternative antimicrobial agents. The advances in bacteriophage therapy highlight their use in controlling a broad spectrum of food-borne pathogens. One requirement for the use of bacteriophages as antibacterials is the characterization of their genomes. In this work, complete genome sequencing and molecular analyses were carried out for three new virulent Salmonella-specific bacteriophages (UAB_Phi20, UAB_Phi78, and UAB_Phi87) able to infect a broad range of Salmonella strains. Sequence analysis of the genomes of UAB_Phi20, UAB_Phi78, and UAB_Phi87 bacteriophages did not evidence the presence of known virulence-associated and antibiotic resistance genes, and potential immunoreactive food allergens. The UAB_Phi20 genome comprised 41,809 base pairs with 80 open reading frames (ORFs); 24 of them with assigned function. Genome sequence showed a high homology of UAB_Phi20 with Salmonella bacteriophage P22 and other P22likeviruses genus of the Podoviridae family, including ST64T and ST104. The DNA of UAB_Phi78 contained 44,110 bp including direct terminal repeats (DTR) of 179 bp and 58 putative ORFs were predicted and 20 were assigned function. This bacteriophage was assigned to the SP6likeviruses genus of the Podoviridae family based on its high similarity not only with SP6 but also with the K1-5, K1E, and K1F bacteriophages, all of which infect Escherichia coli. The UAB_Phi87 genome sequence consisted of 87,669 bp with terminal direct repeats of 608 bp; although 148 ORFs were identified, putative functions could be assigned to only 29 of them. Sequence comparisons revealed the mosaic structure of UAB_Phi87 and its high similarity with bacteriophages Felix O1 and wV8 of E. coli with respect to genetic content and functional organization. Phylogenetic analysis of large terminase subunits confirms their packaging strategies and grouping to the different phage genus type. All these studies are necessary for the development and the use of an efficient cocktail with commercial applications in bacteriophage therapy against Salmonella.

Peanut sensitization pattern in Norwegian children and adults with specific IgE to peanut show age related differences.

BackgroundPeanuts contain potent food allergens and the prevalence of allergy is reported to increase, especially in children. Since peanut sensitization may differ between different geographical regions, we wanted to investigate the sensitization pattern to the individual peanut allergens in a Norwegian population.MethodsCases reported to the Norwegian Food Allergy Register with sera positive to peanut extract were analyzed for specific IgE (sIgE) to the recombinant peanut allergens Ara h 1, Ara h 2, Ara h 3, Ara h 8 and Ara h 9 and to birch pollen extract. Serum samples negative to the above allergens were analyzed for sIgE to Ara h 6, and sIgE to Pru p 3 in peach were analyzed in sera positive to the cross-reactive allergen Ara h 9.ResultsHighest frequency of sIgE to Ara h 2, often co-sensitized to Ara h 1 and 3, were found in the small children up to 6 years of age. From the age of 6 years, sensitization to Ara h 8 was predominant. The sIgE levels to the storage proteins Ara h 1, 2 and 3 were strongly correlated, as was the sIgE levels to Ara h 8 and birch pollen extract. A low sensitization rate of sIgE to Ara h 9 in young adults was observed, which sIgE levels were very strongly correlated to Pru p 3.ConclusionThe sensitization to peanut allergens in a Norwegian population shows a clear age dependent pattern. The results add to the previously published research on the sensitization patterns of peanut sensitized patients in different geographical areas.

Tolerability to dogfish in children with fish allergy

BackgroundFish is a potent food allergen. The aim of this work is to demonstrate that dogfish, a small shark, has low allergenicity in both its clinical tolerance as well as its molecular structure. MethodsWe present a study of 34 paediatric patients with IgE-mediated immediate reactions after eating fish. The diagnosis of several fish allergies was demonstrated by skin prick techniques and determination of specific IgE, in all the cases excluding sensitisation to Anisakis simplex. Open oral challenge test was checked with dogfish. Analysis was by SDS-PAGE of dogfish and other fish (megrim, shark, hake, sole, cod, anchovy and tuna) and Western-blot with “pool” of patients polysensitised sera against extracts of dogfish and other fish, and ELISA – inhibition with the “pool” sera. ResultsThe prick-prick with raw dogfish was slightly positive in six patients, however cooked was negative in 34 cases. The specific IgE showed in the 34 cases class ≥2 for megrim, hake, sole, cod and anchovy, class 0 for tuna in 26 patients, class 0 for emperor in 18 patients and class 0 to Anisakis simplex in all cases. The IgE binding capacity for proteins of allergenic extracts of tested fish revealed, in immunoblotting, the absence of IgE-mediated recognition abstract dogfish by the “pool” of polysensitised patient sera. ConclusionsTesting in vivo and in vitro demonstrated the low allergenicity of dogfish. Dogfish brings an alternative to eating fish in polysensitised patients.

In vitro evaluation of digestive and endolysosomal enzymes to cleave CML-modified Ara h 1 peptides.

Ara h 1 is a major peanut allergen. Processing-induced modifications may modulate the allergenic potency of Ara h 1. Carboxymethyl lysine (CML) modifications are a commonly described nonenzymatic modification on food proteins. In the current study, we tested the ability of digestive and endolysosomal proteases to cleave CML-modified and unmodified Ara h 1 peptides. Mass spectrometric analyses of the digested peptides demonstrate that carboxymethylation of lysine residues renders these peptides refractory to trypsin digestion. We did not detect observable differences in the simulated gastric fluid or endolysosomal digestion between the parental and CML-modified peptides. One of the tested peptides contains a lysine residue previously shown to be CML modified laying in a previously mapped linear IgE epitope, but we did not observe a difference in IgE binding between the modified and parental peptides. Our findings suggest a molecular mechanism for the increased resistance of peanut allergens modified by thermal processing, such as Ara h 1, to digestion in intestinal fluid after heating and could help explain how food processing-induced modifications may lead to more potent food allergens by acting to protect intact IgE epitopes from digestion by proteases targeting lysine residues.

Recent advances in the management of food allergy

Food allergies are common in children and they can be severe. They result in dietary restrictions and significantly affect quality of life. There is currently no cure for food allergies and the mainstream approach to management consists of food avoidance and provision of emergency medication. Recently, a more active approach to management is being adopted, which includes anticipatory testing, early introduction of potential food allergens, active tolerance induction and active risk management, all of which are discussed at length in this review.

Vaccination in food allergic patients

Important potential food allergens in vaccines include egg and gelatin. Rare cases of reactions to yeast, lactose and casein have been reported. It is strongly recommended that when vaccines are being administered resuscitation equipment must be available to manage potential anaphylactic reactions, and that all patients receiving a vaccine are observed for a sufficient period. Children who are allergic to egg may safely receive the measles-mumps-rubella (MMR) vaccine; it may also be given routinely in primary healthcare settings. People with egg allergy may receive influenza vaccination routinely; however, some authorities still perform prior skin-prick testing and give two-stage dosing. The purified chick embryo cell culture rabies vaccine contains egg protein, and therefore the human diploid cell and purified verocell rabies vaccines are preferred in cases of egg allergy. Yellow fever vaccine has the greatest likelihood of containing amounts of egg protein sufficient to cause an allergic reaction in allergic individuals. This vaccine should not be routinely administered in egg allergic patients and referral to an allergy specialist is recommended, as vaccination might be possible after careful evaluation, skin-testing and graded challenge or desensitisation.

Nutrition in early life and the risk of asthma and allergic disease.

The prevalence of reported cases of asthma and allergic disease has seen a marked increase throughout the world since the 1960s, particularly in more developed, westernised countries. A key focus of research in this area has been the possible adverse effects of foetal and infant exposure to food allergens. There is some evidence that foetal and infant exposure to a range of allergens via the mother and her breast milk is important in the development of normal immune tolerance. Current advice is that pregnant and breastfeeding women do not need to avoid potential food allergens unless they are allergic themselves, or are advised to modify their diet by a health professional. Delaying the introduction of common food allergies beyond 6 months is unlikely to reduce the likelihood of food allergy and allergic disease. The findings of current ongoing trials investigating the potential benefits of early introduction on allergenic foods into the diet of children-as well as the comprehensive review of complementary and young-child feeding advice currently being conducted by the Scientific Advisory Committee on Nutrition-will help inform guidance in this area.

Goat's cheese anaphylaxis after cutaneous sensitization by moisturizer that contained goat's milk

The current treatment for atopic eczema includes topical corticosteroid application during exacerbations and regular use of emollients and moisturizers to optimally hydrate affected areas. Many creams to treat dry skin and eczema are advertised as “natural” products, but they may contain potential food allergens. For example, ingredients could include goat's milk, cow's milk, coconut milk or oil, oats, and nut oil. Application of such food allergens to barrier-compromised skin could cause sensitization to the allergen, which leads to severe reactions when the food is subsequently ingested.

Potential food allergens in medications

Potential food allergens in medications

Egg consumption in pregnancy and infant diets: How advice is changing

Eggs are a nutrient-dense, relatively inexpensive and convenient food, suitable for consumption by pregnant and breastfeeding women and infants. However, there appears to be some confusion among the public regarding the safety of egg consumption by these groups. Some evidence suggests that delayed introduction of potential food allergens such as eggs during weaning may be counterproductive for allergenic risk, and that introduction of the allergenic protein during a proposed ‘critical window’, at 4–7 months, may be necessary to induce tolerance. This hypothesis is currently being tested by two major studies, while two expert committees (Scientific Advisory Committee on Nutrition and Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment) are also reviewing evidence on complementary feeding and allergic risk, respectively. This article discusses historic and current advice on egg consumption during pregnancy and breastfeeding and in complementary feeding. It examines the evidence base for the advice in the context of both the microbiological safety of eggs and risks of egg allergy in these groups, presents a new analysis of nationally representative infant feeding data and reviews the latest nutritional composition data for British eggs in the context of the maternal and infant diet. It appears that historic concerns about food safety and allergy may have resulted in unnecessary avoidance of eggs during the introduction of complementary feeding.