Environmental Food Exposure: What Is the Risk of Clinical Reactivity From Cross-Contact and What Is the Risk of Sensitization

Immuno-PCR in the Analysis of Food Contaminants

Food safety is a significant issue of global concern. Consumer safety and government regulations drive the need for the accurate analysis of food contaminants, residues and other chemical constituents of concern. Traditional methods for the detection of food contaminants often present challenges, including lengthy processing times and food matrix interference; they often require expensive equipment, skilled personnel or have limitations in sensitivity or specificity. Developing novel analytical methods that are sensitive, specific, accurate and rapid is therefore crucial for ensuring food safety and the protection of consumers. The immuno-polymerase chain reaction (IPCR) method offers a promising solution in the analysis of food contaminants by combining the specificity of conventional immunological methods with the exponential sensitivity of PCR amplification. This review evaluates the current state of IPCR methods, describes a variety of existing IPCR formats and explores their application in the analysis of food contaminants, including pathogenic bacteria and their toxins, viruses, mycotoxins, allergens, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phthalic acid esters, pesticides, antibiotics and other food contaminants. Depending on the type of analyte, either sandwich or competitive format IPCR methods are predominantly used. This review also examines limitations of current IPCR methods and explores potential advancements for future implementation in the field of food safety.

Precautionary Allergen Labeling: Avoidance for All?

PURPOSE OF REVIEW

Precautionary allergen labeling (PAL) suggests the risk of unintended allergen presence (UAP) in food but is unregulated in most countries and inconsistently applied by food manufacturers. This review evaluates the current use of PAL, its relevance to allergic consumers, and weighs possible advantages and disadvantages of avoiding products with PAL.

RECENT FINDINGS

In most countries, manufacturers are free to decide whether, when, and how to apply PAL resulting in inconsistencies and consumer confusion. Patients with food allergy often interpret PAL incorrectly and without guidance from their health care providers. Health care providers are also prone to misinterpreting PAL, indicating a need for better education. Consumers desire guidance on whether to avoid products with PAL or not. Until further regulatory guidance is available, shared decision-making between patient and provider is required to offer individualized, rather than one-size-fits-all, approaches to PAL.

[Oral allergy syndrome (OAS)]

The pollen-food allergy syndrome, also known as oral allergy syndrome, is characterized by local reactions in the mouth and throat after consuming certain raw plant foods in individuals sensitized to pollen from grass, weeds, and trees. Birch-apple is the prototype of this syndrome, with apple, pear, and plum being the most commonly associated foods. Symptoms are usually limited to the oral cavity but can include systemic reactions, including anaphylaxis. Sensitization to pollen allergens, such as lipid transfer proteins, profilin, and PR-10 proteins, triggers this syndrome. Its prevalence varies by geographic region and the predominant pollen type, affecting between 30% and 60% of food allergies. Diagnosis involves a clinical history, skin tests, and, in ambiguous cases, double-blind, placebo-controlled oral food challenges. Treatment primarily involves avoiding trigger foods.

[Food allergy and environmental contamination]

The interaction between genetic potential and the environment, especially increased urbanization and inadequate waste management, contributes to the manifestation of allergic diseases. Pediatric patients are the most vulnerable, due to the immaturity of the respiratory and immune systems. Prenatal and postnatal exposure to air pollutants, both indoors and outdoors, accelerates or aggravates morbidity and mortality from allergic diseases. The "exposome," which encompasses all environmental exposures throughout life, influences health. Biological and chemical attacks alter the epithelial barrier, triggering inflammatory responses and favoring allergic diseases, such as food allergies. The uncontrolled use of toxic fuels, particulate matter, detergents and other factors contribute to the continuous deterioration of the intestinal epithelial barrier, increasing the risk of allergic diseases. It is important to take urgent action to address these issues and protect the health of the planet.

Understanding food allergy through neuroimmune interactions in the gastrointestinal tract

Food allergies are adverse immune reactions to food proteins in the absence of oral tolerance, and the incidence of allergies to food, including peanut, cow's milk, and shellfish, has been increasing globally. Although advancements have been made toward understanding the contributions of the type 2 immune response to allergic sensitization, crosstalk between these immune cells and neurons of the enteric nervous system is an area of emerging interest in the pathophysiology of food allergy, given the close proximity of neuronal cells of the enteric nervous system and type 2 effector cells, including eosinophils and mast cells. At mucosal sites, such as the gastrointestinal tract, neuroimmune interactions contribute to the sensing and response to danger signals from the epithelial barrier. This communication is bidirectional, as immune cells express receptors for neuropeptides and transmitters, and neurons express cytokine receptors, allowing for the detection of and response to inflammatory insults. In addition, it seems that neuromodulation of immune cells including mast cells, eosinophils, and innate lymphoid cells is critical for amplification of the type 2 allergic immune response. As such, neuroimmune interactions may be critical targets for future food allergy therapies. This review evaluates the contributions of local enteric neuroimmune interactions to the underlying immune response in food allergy and discusses considerations for future investigations into targeting neuroimmune pathways for treatment of food allergies.

Food allergy knowledge, attitude and management among preschool personnel in Malaysia

BACKGROUND

Children are vulnerable, and they may experience their first serious food allergy reaction at school, where they spend much of their time. The present study aims to determine the level of food allergy knowledge, attitude and management (KAM) among preschool personnel in Klang Valley, Malaysia.

METHODS

A cross-sectional study was conducted with 292 personnel working in Klang Valley preschools. The participants completed an online questionnaire asking about sociodemographic information and food allergy KAM. Mann-Whitney U and chi-squared tests were used to compare the KAM level between public and private preschool personnel and examine the association of KAM of food allergy with various sociodemographic factors, respectively.

RESULTS

Some 86.3% of the participants demonstrated a low level of food allergy knowledge, 64.7% showed a negative food allergy attitude and 57.9% indicated fair food allergy management. The total mean score for food allergy knowledge was higher (p < 0.01) among the private preschool personnel compared to the public group, although there was no significant difference in attitude (p = 0.244) or practice (p = 0.171). Age group (p < 0.01) and monthly income (p < 0.05) were significantly associated with the level of attitude, whereas no sociodemographic factor was associated with knowledge and management of food allergy.

CONCLUSIONS

Most preschool personnel in Klang Valley have a low level of food allergy knowledge, negative attitudes and a fair level of ability to manage food allergy reactions. The findings of the present study may guide future studies to improve the food allergy KAM of preschool personnel and provide a safer environment for children with food allergies.

Impact of the exposome on food allergy development

PURPOSE OF REVIEW

The increasing global prevalence of food allergy indicates that environmental exposures are likely contributing to food allergy development. This review summarizes recent studies on how specific factors within the external exposome may impact the development of food allergy.

RECENT FINDINGS

There is strong evidence that nonoral exposure to food allergens within the living environment is a risk factor for food sensitization and food allergy. The role of air pollution in food allergy development remains unclear, as cohort studies have not found consistent relationships between air pollutant exposure and food sensitization. Early-life microbial exposures linked to a rural lifestyle are likely protective against food allergy development, possibly through alteration of the infant microbiome. In contrast, factors associated with urbanization and decreased exposure to microbes may contribute to food allergy development. Recent studies on the role of residential greenness in food allergy development suggest either no relationship or a possible increased risk for food allergy.

SUMMARY

The external exposome comprises a number of exposures that can modify food allergy risk. Improved understanding of how complex environmental exposures interact with genetic factors will be necessary for developing effective interventions aimed at preventing food allergy development in children.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Relationship between Food Allergy and Endotoxin Concentration and the Toleration Status at 2 Years: The Japan Environment and Children's Study

Changes in household endotoxin concentration may affect the prognosis of food allergy (FA), but data on the association between household endotoxin concentration and an already-developed FA are scarce. Thus, we investigated the association between environmental endotoxin exposure and tolerance to hen's egg (HE) and cow's milk (CM) using data from children participating in the Japan Environment and Children's Study who had HE allergies (n = 204) and CM allergy (n = 72) in their first year of life. We grouped the endotoxin results into quartiles 1-4 (Q1-Q4). In children with HE allergy and with CM allergy, there was no significant difference in the prevalence of tolerance to HE and CM at 2 years old when comparing endotoxin levels of the children in Q1 with those in Q2, Q3, and Q4, respectively. However, subgroup analyses by the presence of eczema and causal foods revealed that children in Q1 had a lower prevalence of tolerance to foods in some subgroup analyses and lower causal allergen-specific immunoglobulin G4 levels. Although an individually based approach against endotoxin according to background characteristics, such as eczema and causal foods, is necessary, preventing excessive endotoxin removal might contribute to FA resolution in some children.

Role of basal sweating in maintaining skin hydration in the finger: A long-standing paradox in dry skin resolved

A long-standing paradox in dermatology is why skin dehydration in the fingers can be triggered by repeated water exposure despite the action of water to hydrate skin tissue. Potential clues might be provided by identifying a mechanism through which water is held in the skin of the fingers. We speculated that this mechanism would be impaired after repeated water exposure. Here, we investigated whether there might be glabrous skin-specific water-holding machinery and whether this machinery might be impaired in dry skin/hand eczema. We examined this by using an impression-mould technique, allowing for an accurate quantification of sweat gland/duct activity and optical coherence tomography. Unlike in hairy skin, sweat pores were rarely detected at the folds of the finger at baseline. Surprisingly, after water exposure, sweat pores at the folds opened and those at the ridges closed in healthy controls (HCs). Sweating in the dermal folds of the hands correlated with skin hydration, and decreased in dry skin/hand eczema, suggesting that its impairment may be one of the causes of dry skin. After repeated water exposure, basal sweating response at the folds was exhausted in patients with dry skin/hand eczema as well as HCs. This exhaustion was rescued by exposing individuals to high humidity. Basal sweating defects would be a target for dry skin/hand eczema. Maintaining basal sweating responses in the finger is the best preventive measures in achieving prevention of dry skin/hand eczema.

Tracking Arachis hypogaea Allergen in Pre-Packaged Foodstuff: A Nanodiamond-Based Electrochemical Biosensing Approach

The present work reports a nanodiamond-based voltammetric immunosensing platform for the analysis of a food allergen (Ara h 1) present in peanuts (Arachis hypogaea). The possibility of the usage of nanodiamonds (d = 11.2 ± 0.9 nm) on screen-printed carbon electrodes (SPCE/ND) in a single-use two-monoclonal antibody sandwich assay was studied. An enhanced electroactive area (~18%) was obtained and the biomolecule binding ability was improved when the 3D carbon-based nanomaterial was used. The antibody-antigen interaction was recognized through the combination of alkaline phosphatase with 3-indoxyl phosphate and silver ions. Linear Sweep Voltammetry (LSV) was applied for fast signal acquisition and scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) support the voltammetric approach and confirm the presence of silver particles on the electrode surface. The proposed immunosensor provided a low limit of detection (0.78 ng·mL−1) and highly precise (RSD < 7.5%) and accurate results. Quantification of Ara h 1 in commercial foodstuffs (e.g., crackers, cookies, protein bars) that refer to the presence of peanuts (even traces) on the product label was successfully achieved. The obtained data were in accordance with recovery results (peanut addition, %) and the foodstuff label. Products with the preventive indication “may contain traces” revealed the presence of peanuts lower than 0.1% (m/m). The method’s results were validated by comparison with an enzyme-linked immunosorbent assay. This allows confident information about the presence of allergens (even at trace levels) that leads to profitable conditions for both industry and consumers.

Association of egg protein levels in dust with allergy status and related factors

BACKGROUND

Levels of peanut protein in dust have been reported to be associated with sensitization and allergy to it, so controlling food protein in dust may help prevent food allergy. However, studies of factors associated with egg protein levels in dust are scarce. This study aimed to determine the factors contributing to egg protein levels in dust.

METHODS

This cross-sectional study included 159 participants in the Sub-Cohort Study of the Japan Environment and Children's Study in Yamanashi Prefecture at a 6 year follow up. House dust at 6 years was collected and egg protein concentrations were measured for whole egg protein. Household factors, including the maternal frequency of egg consumption, were assessed by questionnaires. A linear regression model was used to analyze the effect of household environmental factors on egg protein in dust.

RESULTS

In multivariate analysis, frequent maternal egg consumption (≥5 times a week) was associated with higher egg protein concentrations in house dust (β = 0.96, P = 0.01). The egg protein load was significantly associated with a higher number of cohabitants (≥5, β = 0.85, P = 0.02) in addition to frequent maternal egg consumption. Among the participants, 140 (88.1%) had no egg allergy, 15 (9.4%) were egg tolerant, and 4 (2.5%) had an egg allergy at 6 years old. There was no significant association between the current egg allergy status and egg protein concentrations in dust.

CONCLUSIONS

The frequency of maternal egg consumption and the number of inhabitants are contributing factors to egg protein levels in dust.

Voltammetric Immunosensor to Track a Major Peanut Allergen (Ara h 1) in Food Products Employing Quantum Dot Labels

Tracking unreported allergens in commercial foods can avoid acute allergic reactions. A 2-step electrochemical immunosensor was developed for the analysis of the peanut allergen Ara h 1 in a 1-h assay (<15 min hands-on time). Bare screen-printed carbon electrodes (SPCE) were used as transducers and monoclonal capture and detection antibodies were applied in a sandwich-type immunoassay. The short assay time was achieved by previously combining the target analyte and the detection antibody. Core/shell CdSe@ZnS Quantum Dots were used as electroactive label for the detection of the immunological interaction by differential pulse anodic stripping voltammetry. A linear range between 25 and 1000 ng·mL-1 (LOD = 3.5 ng·mL-1), an adequate precision of the method (Vx0 ≈ 6%), and a sensitivity of 23.0 nA·mL·ng-1·cm-2 were achieved. The immunosensor was able to detect Ara h 1 in a spiked allergen-free product down to 0.05% (m/m) of peanut. Commercial organic farming cookies and cereal and protein bars were tested to track and quantify Ara h 1. The results were validated by comparison with an ELISA kit.

Interrupting reactivation of immunologic memory diverts the allergic response and prevents anaphylaxis

BACKGROUND

IgE production against innocuous food antigens can result in anaphylaxis, a severe life-threatening consequence of allergic reactions. The maintenance of IgE immunity is primarily facilitated by IgG+ memory B cells, as IgE+ memory B cells and IgE+ plasma cells are extremely scarce and short-lived, respectively.

OBJECTIVE

Our aim was to investigate the critical requirements for an IgE recall response in peanut allergy.

METHODS

We used a novel human PBMC culture platform, a mouse model of peanut allergy, and various experimental readouts to assess the IgE recall response in the presence and absence of IL-4Rα blockade.

RESULTS

In human PBMCs, we have demonstrated that blockade of IL-4/IL-13 signaling aborted IgE production after activation of a recall response and skewed the cytokine response away from a dominant type 2 signature. TH2A cells, identified by single-cell RNA sequencing, expanded with peanut stimulation and maintained their pathogenic phenotype in spite of IL-4Rα blockade. In mice with allergy, anti-IL-4Rα provided long-lasting suppression of the IgE recall response beyond antibody treatment and fully protected against anaphylaxis.

CONCLUSION

The findings reported here advance our understanding of events mediating the regeneration of IgE in food allergy.

Occupational food allergy

PURPOSE OF REVIEW

Occupation is an important contributing factor in the presentation of allergic disease in adults. This review article focuses on the contribution of occupation to the development and presentation of food allergies.

RECENT FINDINGS

A variety of occupations involve repeated transdermal and respiratory exposures to food-related allergens, which can result in sensitization. A sensitized individual can then manifest symptoms of food allergy after ingestion of the relevant food, even in a nonoccupational setting. Cooks and other food-processing workers bear increased risk for being sensitized to foods. Although any type of food can become a causal agent for this phenomenon, published cases of occupational food allergy concentrate on fish and seafood allergies among cooks and food-processing workers who come into direct contact with these foods. Latex-fruit syndrome is also a relatively common form of occupational food allergy among healthcare workers. Hand eczema has also been shown to be an important risk factor for occupational sensitization to food allergens.

SUMMARY

The association of occupation with food allergy in adults has been documented. Considering the under-recognized nature of this phenomenon, we should be aware in our clinical practice that a patient's occupation might be relevant to his or her food allergy.

The External Exposome and Food Allergy

PURPOSE OF REVIEW

The recent increase in childhood food allergy prevalence strongly suggests that environmental exposures are contributing to food allergy development. This review summarizes current knowledge about the role of the external exposome in food allergy.

RECENT FINDINGS

There is growing evidence that environmental exposure to food antigens in house dust through non-oral routes contributes to food sensitization and allergy. Co-exposure to environmental adjuvants in house dust, such as microbial products and fungal allergens, may also facilitate allergic sensitization. While a high-microbe environment is associated with decreased atopy, studies are mixed on whether endotoxin exposure protects against food sensitization. Several chemicals and air pollutants have been associated with food sensitization, but their role in food allergy remains understudied. Children are exposed to numerous environmental agents that can influence food allergy risk. Further studies are needed to identify the key early-life exposures that promote or inhibit food allergy development.

Food allergen knowledge, attitude and practices among UK consumers: A structural modelling approach

Food allergies are becoming more prevalent and affect up to 1-2% of adults and 5-8% of children in the UK. This study investigated the food allergen knowledge, attitude towards food allergens and food allergy management practices among food allergic and intolerant consumers and/or their family members and carers. Questionnaires were distributed at three major Free From events in the UK in 2017 and 2018. Structural Equation Modelling (SEM) was used as a confirmatory technique to determine the model's validity. Cereals containing gluten, milk and eggs were the most common triggers reported by the consumers. Other trigger foods such as chocolate, garlic, maize, onions, red and white meat, spices, and fruits such as apples and cherries were also reported. Consumers demonstrated very good understanding on the severity of allergic reactions, prevention method and hidden egg ingredients. Overall, consumers were relatively good in the knowledge section. The participants were motivated in their personal allergen avoidance towards food allergens especially in checking food labels, preference for more free from product choices and handwashing. Consumers did not rely on dietary apps or social media to find out about allergen-free food products. Both knowledge and attitude did not translate into food allergy management practices. Significant correlation between knowledge and attitude was identified suggesting that as knowledge decreases, so will their attitude scores. This study suggests that targeted and systematic food allergy management topics and peer support could be used to improve consumers' knowledge and attitude to positively impact food allergen handling practices.