Peanut and hazelnut traces in cookies and chocolates: Relationship between analytical results and declaration of food allergens on product labels

The Magnitude and Impact of Food Allergens and the Potential of AI-Based Non-Destructive Testing Methods in Their Detection and Quantification

Reaction to food allergens is on the increase and so is the attending cost on consumers, the food industry, and society at large. According to FDA, the "big-eight" allergens found in foods include wheat (gluten), peanuts, egg, shellfish, milk, tree nuts, fish, and soybeans. Sesame was added to the list in 2023, making the target allergen list nine instead of eight. These allergenic foods are major ingredients in many food products that can cause severe reactions in those allergic to them if found at a dose that can elicit a reaction. Defining the level of contamination that can elicit sensitivity is a work in progress. The first step in preventing an allergic reaction is reliable detection, then an effective quantification method. These are critical steps in keeping contaminated foods out of the supply chain of foods with allergen-free labels. The conventional methods of chemical assay, DNA-PCR, and enzyme protocols like enzyme-linked immunosorbent assay are effective in allergen detection but slow in providing a response. Most of these methods are incapable of quantifying the level of allergen contamination. There are emerging non-destructive methods that combine the power of sensors and machine learning to provide reliable detection and quantification. This review paper highlights some of the critical information on the types of prevalent food allergens, the mechanism of an allergic reaction in humans, the measure of allergenic sensitivity and eliciting doses, and the conventional and emerging AI-based methods of detection and quantification-the merits and downsides of each type.

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.

Accidental allergic reactions to food in adolescents and adults: An overview of the factors involved and implications for prevention

Accidental allergic reactions to food are one of the major problems in adult patients diagnosed with food allergy. Such reactions occur frequently, are often severe and are associated with higher medical and non-medical costs. The aim of this Perspective is to provide insight into the different factors involved in the occurrence of accidental allergic reactions and to present an overview of practical implications for effective preventive measures. Several factors affect the occurrence of accidental reactions. These factors are related to the patient, health care, or food. The most important patient-related factors are age, social barriers to disclosing their allergy and non-adherence to the elimination diet. With regards to healthcare, the degree to which clinical practice is tailored to the individual patient is an important factor. The major food-related factor is the absence of adequate precautionary allergen labeling (PAL) guidelines. Since many factors are involved in accidental allergic reactions, different preventive strategies are needed. It is highly recommended that health care be tailored to the individual patient, with regard to education about the elimination diet, support on behavioral and psychosocial aspects, usage of shared decision-making and taking into account health literacy. In addition, it is crucial that steps are taken to improve policies and guidelines for PAL.

Precautionary Allergen Labeling: What Advice Is Available for Health Care Professionals, Allergists, and Allergic Consumers?

In most countries, the use of precautionary allergen labeling (PAL) is not governed by regulation. PAL was initially identified as a judicious risk management measure to address instances of "unavoidable" cross-contact with priority food allergens during food processing. However, PAL has gradually been devalued in part due to overuse and inconsistent application by the food industry. Currently, most food products do not contain detectable allergen residue or contain only low concentrations of residue of the allergens declared using PAL; however, occasionally, high concentrations of allergen residue are reported, rendering it an ineffective risk communication tool for allergic consumers. In this context, several reasons exist that make the consumption of products bearing a PAL statement not advisable for people with food allergies. The main reason is that the risk is generally not correlated with the statement used by manufacturers. Because of the increased use of PAL on prepackaged food products, and to maximize food choices for allergic individuals, health care professionals increasingly advise some patients considered to be "not highly allergic" to consume products bearing a PAL statement. This article explains why the consumption of products with PAL is not advisable without having a full clinical evaluation and knowledge that an allergen risk assessment has been conducted. It also discusses the perspectives for a better use of PAL on the basis of the recent Food and Agricultural Organization/World Health Organization recommendations on food allergens.

Tree Nuts and Peanuts as a Source of Beneficial Compounds and a Threat for Allergic Consumers: Overview on Methods for Their Detection in Complex Food Products

Consumption of tree nuts and peanuts has considerably increased over the last decades due to their nutritional composition and the content of beneficial compounds. On the other hand, such widespread consumption worldwide has also generated a growing incidence of allergy in the sensitive population. Allergy to nuts and peanuts represents a global relevant problem, especially due to the risk of the ingestion of hidden allergens as a result of cross-contamination between production lines at industrial level occurring during food manufacturing. The present review provides insights on peanuts, almonds, and four nut allergens—namely hazelnuts, walnuts, cashew, and pistachios—that are likely to cross-contaminate different food commodities. The paper aims at covering both the biochemical aspect linked to the identified allergenic proteins for each allergen category and the different methodological approaches developed for allergens detection and identification. Attention has been also paid to mass spectrometry methods and to current efforts of the scientific community to identify a harmonized approach for allergens quantification through the detection of allergen markers.

Quantification of Casein in Baked Food Products by Selective Analysis of Phosphorylated Peptides Using Fluorous Derivatization with Liquid Chromatography-Tandem Mass Spectrometry Method

Casein is one of the allergen proteins present in milk. Therefore, a quantification method for the selective analysis of casein using fluorous derivatization with LC-tandem mass spectrometry (LC-MS/MS) was developed. After two allergen proteins (α_S1-casein and β-casein) extracted from baked sugar cookies were tryptic digested, the obtained phosphorylated peptides were selectively derivatized by β-elimination with Ba(NO₃)₂ under basic condition and Michael addition with perfluoroalkylthiol (1H,1H,2H,2H-perfluorooctanethiol, PFOT). In this study, YKVPQLEIVPN(pSer)AQQR (104-119 fragment from α_S1-casein) and FQ(pSer)EEQQQTEDELQDK (33-48 fragment from β-casein) obtained by tryptic digestion were selected as target peptides. The phosphorylated serine residue in each peptide was converted to a perfluoroalkyl group by derivatization. The obtained fluorous-derivatized peptides were analyzed by LC-MS/MS, to which a fluorous LC column was connected. Therefore, it was possible to analyze casein without being affected by the matrix components in the baked food sample. When the present method was applied to cookies with arbitrary amounts of α_S1-casein and β-casein, the obtained quantification values were in good agreement with the arbitrary amounts spiked. The quantification limits of α_S1- and β-casein in cookie analysis were 246 and 152 ng/g, respectively. Hence, this method can be used to analyze trace amounts of allergen proteins present in the baked food.

Peanut and hazelnut occurrence as allergens in foodstuffs with precautionary allergen labeling in Canada

Precautionary allergen labeling (PAL) is widely used by food industries. Occurrence studies revealed that few analyzed products contained the allergen(s) present in the statement, but little is known in Canada. To improve manufacturing practices and better manage allergen cross-contamination, occurrence data is needed to determine the exposure of allergic individuals eating those products. Samples were analyzed for peanuts (n = 871) and hazelnuts (n = 863) using ELISA methods. Within samples analyzed for peanuts, 72% had a PAL (n = 628), 1% had peanuts as a minor ingredient (n = 9) and 27% were claimed “peanut-free” (n = 234). Most hazelnut samples had a PAL for tree nuts/hazelnuts (94%; n = 807) with 6% claimed “nut-free” (n = 56). Peanuts and hazelnuts were found in 4% (0.6–28.1 ppm) and 9% (0.4–2167 ppm) of all samples, respectively. Chocolates were mostly impacted; they should be treated apart from other foods and used in risk assessments scenarios to improve manufacturing practices, reducing unnecessary PAL use.

Probabilistic risk assessment for milk in dark chocolate, cookies and other baked goods with PAL sold in Canada

The risk of having an allergic reaction in milk-allergic individuals consuming products with precautionary allergen labelling (PAL) for milk has been rarely studied in products such as dark chocolate, cookies, and other baked goods. A probabilistic risk assessment model was developed to estimate potential risks. Milk occurrence and contamination levels were reported in a previous article from our group. Dose-response curves for milk were constructed using values (n = 1078) from published double-blind placebo-controlled food challenges. Canadian consumption data was extracted from a national survey, and a homemade survey involving food-allergic Canadians. Milk eliciting doses (ED) were 0.23 (ED₀₁), 1.34 (ED₀₅), 3.42 (ED₁₀), and 16.3 (ED₂₅) mg of milk protein (Log-Normal distribution). Average exposures, per eating occasion, were 24 mg (dark chocolate), 3.9 mg (baked goods), and 0.20 mg (cookies) of milk proteins. The estimated risk of having a milk-induced allergic reaction by consuming foods with PAL for milk was higher for dark chocolate (16%; 15,881/100,000) than baked goods (3.8%; 3802/100,000) or cookies (0.6%; 646/100,000) in milk-allergic Canadians. Dark chocolate, cookies, and baked goods with PAL for milk, should be avoided by milk-allergic Canadians (consuming or not products with PAL) to prevent allergic reactions.

Occurrence of milk and egg allergens in foodstuffs in Canada

Food allergies are life-threatening conditions that allergic individuals can avoid by consulting the food labels before consuming. Precautionary allergen labelling (or PAL), to warn against possible allergen cross-contamination, is widely used by food industries, reducing the food choices for allergic individuals. In Canada, there is limited information on the actual occurrence of allergens in products with a PAL related to the given allergen. This study attempted to fill the data gap by evaluating the occurrence of milk and egg allergens in Canadian products with PAL. A total of 1125 samples were analysed for milk and 840 for eggs, with 23% and 7% of these samples showing positive detection of ≥2.5 mg kg^-1 for milk and ≥0.245 mg kg^-1 for eggs. Chocolate products gave the largest number of positive results. Although the proportion of positive results was low, the levels detected reached 6471 mg kg^-1 in a chocolate sample and were indicative of possible health consequences, if PAL was ignored by allergic consumers. The occurrence data generated is destinated to be used in exposure and risk assessments, to support allergen management linked to cross-contamination, with the possible development of allergen action levels that would be used by food industries, thus improving a risk-based approach for the application of PAL.

Can we define a level of protection for allergic consumers that everyone can accept?

Substantial progress has been made in characterising the risk associated with exposure to allergens in food. However, absence of agreement on what risk is tolerable has made it difficult to set quantitative limits to manage that risk and protect allergic consumers effectively. This paper reviews scientific progress in the area and the diverse status of allergen management approaches and lack of common standards across different jurisdictions, including within the EU. This lack of regulation largely explains why allergic consumers find Precautionary Allergen Labelling confusing and cannot rely on it. We reviewed approaches to setting quantitative limits for a broad range of food safety hazards to identify the reasoning leading to their adoption. This revealed a diversity of approaches from pragmatic to risk-based, but we could not find clear evidence of the process leading to the decision on risk acceptability. We propose a framework built around the criteria suggested by Murphy and Gardoni (2008) for approaches to defining tolerable risks. Applying these criteria to food allergy, we concluded that sufficient knowledge exists to implement the framework, including sufficient expertise across the whole range of stakeholders to allow opinions to be heard and respected, and a consensus to be achieved.

Use of IHF-QD Microscopic Analysis for the Detection of Food Allergenic Components: Peanuts and Wheat Protein

The aim of the study was to analytically evaluate quantum dots in immunohistofluorescence (IHF-QD) microscopic imaging as detectors of food allergens—peanut and wheat. The experiment was designed as two in silico experiments or simulations: (a) models of pastry samples were prepared with the addition of allergenic components (peanut and wheat protein components) and without the addition of allergenic components, and (b) positive and negative commercial samples underwent food allergen detection. The samples from both simulations were tested by the ELISA and IHF-QD microscopic methods. The primary antibodies (secondary antibodies to a rabbit Fc fragment with labeled CdSe/ZnS QD) were labelled at 525, 585, and 655 nm emissions. The use of quantum dots (QDs) has expanded to many science areas and they are also finding use in food allergen detection, as shown in the study. The study indicated that differences between the ELISA and IHF-QD microscopic methods were not observable among experimentally produced pastry samples with and without allergenic components, although differences were observed among commercial samples. The important value of the study is certainly the differences found in the application of different QD conjugates (525, 585, and 655). The highest contrast was found in the application of 585 QD conjugates that can serve for the possible quantification of present food allergens—peanuts and wheat. The study clearly emphasized that QD can be used for the qualitative detection of food allergens and can represent a reliable analytical method for food allergen detection in different food matrixes.

Undeclared allergens in imported packaged food for retail in Australia

The Australia New Zealand Food Standards Code (the Code) requires a declaration of the presence of 11 different allergens made through the label on a food product. Most food recalls in Australia are now due to undeclared allergens . This survey determined the extent of undeclared allergens in imported food products on the Asian retail market in Australia. A total of 50 imported packaged foods were selectively purchased from local Asian grocery retail stores in Melbourne and the presence of undeclared gluten, milk, peanut and egg determined. Analysis was performed using commercial enzyme-linked immunosorbent assay (ELISA) (R-Biopharm). Thirty-seven undeclared allergens (gluten n = 12, milk n = 12, peanut n = 6, and egg n = 7) were detected in 23 of the 50 products analysed (46%), with 18% containing multiple undeclared allergens. The high number of undeclared allergens is alarming and in line with the increasing number of food recalls and anaphylaxis recorded in Australia.

Estimated risk reduction to packaged food reactions by epicutaneous immunotherapy (EPIT) for peanut allergy

BACKGROUND

Peanut allergy is a generally persistent, sometimes life-threatening food allergy. With no treatments demonstrating the ability to cure a food allergy, the focus of drugs in development has been on providing a level of protection against accidental exposure reactions. However, no study has estimated the relative risk reduction of a food-allergic population receiving a specific immunotherapeutic treatment for their allergies.

OBJECTIVE

To estimate the relative risk reduction when consuming peanut-contaminated packaged food products in a double-blind, placebo-controlled Phase 3 study population of children treated with epicutaneous immunotherapy (EPIT) for 12 months with either a patch containing 250 μg peanut protein (250-μg patch) or a placebo patch.

METHODS

The probability of an allergic reaction due to the unintended presence of peanut protein in packaged food products was modeled per study group and food category combination using Monte Carlo simulations. Risks per eating occasion of a contaminated packaged food product and the number of individuals per study population predicted to react on a yearly basis were investigated.

RESULTS

The population treated with the 250-μg patch demonstrated a significantly increased dose-response distribution after 12 months of treatment, which resulted in a relative risk reduction of 73.2% to 78.4% when consuming peanut-contaminated packaged food products. In contrast, no statistically significant change was observed for the placebo group at the 12-month point.

CONCLUSION

Our study estimates a substantial relative risk reduction for allergic reactions among peanut-allergic children after 12 months of EPIT with the 250-μg patch, supporting the potential real-world clinical relevance of this investigational immunotherapy and its possible role as a future therapy for peanut-allergic children. ClinicalTrials.gov Identifier: NCT02636699.

Addressing Complex Matrix Interference Improves Multiplex Food Allergen Detection by Targeted LC-MS/MS

The frequent use of precautionary food allergen labeling (PAL) such as "may contain" frustrates allergic individuals who rely on such labeling to determine whether a food is safe to consume. One technique to study whether foods contain allergens is targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) employing scheduled multiple reaction monitoring (MRM). However, the applicability of a single MRM method to many commercial foods is unknown as complex and heterogeneous interferences derived from the unique composition of each food matrix can hinder quantification of trace amounts of allergen contamination. We developed a freely available, open source software package MAtrix-Dependent Interference Correction (MADIC) to identify interference and applied it with a method targeting 14 allergens. Among 84 unique food products, we found patterns of allergen contamination such as wheat in grains, milk in chocolate-containing products, and soy in breads and corn flours. We also found additional instances of contamination in products with and without PAL as well as highly variable soy content in foods containing only soybean oil and/or soy lecithin. These results demonstrate the feasibility of applying LC-MS/MS to a variety of food products with sensitive detection of multiple allergens in spite of variable matrix interference.

Quantitative risk reduction through peanut immunotherapy: Safety benefits of an increased threshold in Europe

BACKGROUND

The clinical relevance of increasing an allergic individual's peanut sensitivity threshold by immunotherapy, that is, eliciting dose (ED) to 300 or 1000 mg peanut protein, has not been previously characterized in a European population. In this study, we quantify the clinical benefits of an increased threshold of reaction following immunotherapy for the peanut-allergic individual.

METHODS

Quantitative risk assessments incorporated numerous inputs to predict the risk of an allergic reaction after exposure to residual peanut protein in packaged foods. The three primary inputs for the risk assessment were the peanut-allergic individual's clinical threshold value, the amount of food consumed per eating occasion of selected packaged foods, and the concentration of peanut protein in the consumed product. Individual risk reductions were calculated for both children and adolescents-adults.

RESULTS

Using available consumption and packaged food contamination data, children reaching an ED of 300 mg (if initial ED ≤ 100 mg) or 1000 mg (if initial ED 300 mg) achieved >99.99% risk reduction. Adolescents-adults also achieved >99.99% risk reduction in all cases but one. Adolescents-adults who reached an ED of 300 mg (if initial ED ≤ 100 mg) achieved 99.3%-99.9% risk reduction when consuming ice cream.

CONCLUSIONS

It is concluded that an increase in threshold following immunotherapy which achieves an eliciting dose of 300 or 1000 mg peanut protein is clinically relevant for the European peanut-allergic population. Benefits of an increased threshold include a significant reduction in risk due to traces of peanut protein.

Development of a strategy for the quantification of food allergens in several food products by mass spectrometry in a routine laboratory

Worldwide, mass spectrometry is widely used to detect and quantify food allergens, especially in complex and processed food products. Yet, the absence of a regulatory framework for the developed methods has led to a lack of harmonization between laboratories. In this study, ten allergens were analyzed in eight food products by UHPLC-MS/MS, in order to establish criteria for the retention time, variation tolerance, the ion ratio deviation, and the signal-to-noise ratio for allergen detection. The set of criteria should help laboratories to compare results and avoid false positives and negatives. Furthermore, a strategy combining standard addition and labeled peptide correction was used to quantify milk, soy, peanut, and egg allergens in eight food products. This strategy is particularly interesting for routine laboratories, which receive hundreds of samples and cannot use an external calibration curve for each sample.

Anaphylaxis to packaged foods in Australasia

AIMS

To examine reports of anaphylaxis in Australasia from consumption of packaged food products with or without precautionary allergen labelling (PAL), where the known allergen triggers were not a listed ingredient.

METHODS

A questionnaire was sent to all members of the Australasian Society of Clinical Immunology and Allergy (n = 548). Participants were asked to complete a survey reporting whether they have had seen any patients over the last 3 months reporting anaphylaxis following ingestion of a packaged food where the suspected food allergen was not a listed ingredient.

RESULTS

Of the n = 548 members approached, n = 198 responded (response rate 36.1%).There were 14 reports of anaphylaxis to packaged foods (where the suspected allergen was not a listed ingredient), which met the case definition from a total of 198 respondents over the 9-month period. Of those reactions, 50.0% (confidence interval 95% 21-78) were reported from foods that did not have a PAL statement, and 50.0% (confidence interval 95% 21-78) were due to peanuts.

CONCLUSION

Anaphylaxis to undeclared allergens was not rare and did not appear to depend on whether the product was labelled with precautionary advice. There is currently no reliable labelling system that can inform food-allergic consumers of safer food choices. Improvements in the regulation of food labelling with PAL are required.

Biosensing Based on Nanoparticles for Food Allergens Detection

Food allergy is one of the major health threats for sensitized individuals all over the world and, over the years, the food industry has made significant efforts and investments to offer safe foods for allergic consumers. The analysis of the concentration of food allergen residues in processing equipment, in raw materials or in the final product, provides analytical information that can be used for risk assessment as well as to ensure that food-allergic consumers get accurate and useful information to make their food choices and purchasing decisions. The development of biosensors based on nanomaterials for applications in food analysis is a challenging area of growing interest in the last years. Research in this field requires the combined efforts of experts in very different areas including food chemistry, biotechnology or materials science. However, the outcome of such collaboration can be of significant impact on the food industry as well as for consumer’s safety. These nanobiosensing devices allow the rapid, selective, sensitive, cost-effective and, in some cases, in-field, online and real-time detection of a wide range of compounds, even in complex matrices. Moreover, they can also enable the design of novel allergen detection strategies. Herein we review the main advances in the use of nanoparticles for the development of biosensors and bioassays for allergen detection, in food samples, over the past few years. Research in this area is still in its infancy in comparison, for instance, to the application of nanobiosensors for clinical analysis. However, it will be of interest for the development of new technologies that reduce the gap between laboratory research and industrial applications.

Food allergen labelling: "May contain" evidence from Malaysia

Food allergen labelling is mandatory and regulated whilst precautionary allergen labelling (PAL) remains voluntary in most countries. It is the aim of this study to identify the food allergens declared in food products sold in a developing country and to what extent food allergens and PAL are emphasised in the products. A total of 505 food and beverages (snacks, baked goods, confectionary, baby food, condiments & jams, beverages, powder & paste, instant food, chilled & frozen food and canned food) were evaluated in Malaysia. Soybean represents the largest group of food allergen declared in labels, followed by wheat and milk products. Thirteen variations of contains statement were found with "Contains [allergen(s)]" being the most common (55.02%). There were 22 different types of "may contain" statements with 'May contain traces of [allergen(s)]' being the most common advice labelling used (55.41%). Different font type or emphasis such as brackets (51.57%) and bold font (33.86%) were used to inform consumers about presence of allergens. The national regulations on food allergen labelling are then critically contrasted with other Asian countries and the EU Regulation No. 1169/2011, which represents one of the most stringent food regulations in the world. Improving current allergen labelling limitations and practices would be of great benefit to consumers to prevent risk of food hypersensitivity.

Quantitative Assessment of the Safety Benefits Associated with Increasing Clinical Peanut Thresholds Through Immunotherapy

BACKGROUND

Peanut immunotherapy studies are conducted with the aim to decrease the sensitivity of patients to peanut exposure with the outcome evaluated by testing the threshold for allergic response in a double-blind placebo-controlled food challenge. The clinical relevance of increasing this threshold is not well characterized.

OBJECTIVE

We aimed to quantify the clinical benefit of an increased threshold for peanut-allergic patients.

METHODS

Quantitative risk assessment was performed by matching modeled exposure to peanut protein with individual threshold levels. Exposure was modeled by pairing US consumption data for various food product categories with potential contamination levels of peanut that have been demonstrated to be present on occasion in such food products. Cookies, ice cream, doughnuts/snack cakes, and snack chip mixes were considered in the risk assessment.

RESULTS

Increasing the baseline threshold before immunotherapy from 100 mg or less peanut protein to 300 mg peanut protein postimmunotherapy reduces the risk of experiencing an allergic reaction by more than 95% for all 4 food product categories that may contain trace levels of peanut residue. Further increase in the threshold to 1000 mg of peanut protein had an additional quantitative benefit in risk reduction for all patients reacting to 300 mg or less at baseline.

CONCLUSIONS

We conclude that achieving thresholds of 300 mg and 1000 mg of peanut protein by peanut immunotherapy is clinically relevant, and that the risk for peanut-allergic patients who have achieved this increased threshold to experience an allergic reaction is reduced in a clinically meaningful way.

Threshold Dose Distribution in Walnut Allergy

BACKGROUND

In food allergy, eliciting doses (EDs) of foods on a population level can improve risk management and labeling strategies for the food industry and regulatory authorities. Previously, data available for walnut were unsuitable to determine EDs.

OBJECTIVE

The objective of this study was to determine EDs for walnut allergic adults and to compare with previously established threshold data for peanut and tree nuts.

METHODS

Prospectively, adult subjects with a suspected walnut allergy underwent a low-dose double-blind, placebo-controlled food challenge. Individual no observed and lowest observed adverse effect levels were determined and log-normal, log-logistic, and Weibull models were fit to the data. Estimated ED values were calculated for the ED_5, ED₁₀, and ED₅₀, the dose respectively predicted to provoke an allergic reaction in 5%, 10%, and 50% of the walnut allergic population.

RESULTS

Fifty-seven subjects were challenged and 33 subjects were confirmed to be walnut allergic. Objective symptoms occurred in 20 of the positive challenges (61%). The cumulative EDs in the distribution models ranged from 3.1 to 4.1 mg for the ED₀₅, from 10.6 to 14.6 mg walnut protein for the ED₁₀, and from 590 to 625 mg of walnut protein for the ED₅₀.

CONCLUSIONS

Our data indicate that population EDs for walnut are slightly higher compared with those for peanut and hazelnut allergy. Currently available data indicate that the ED values for hazelnut could be used as a conservative temporary placeholder when implementing risk management strategies for other tree nuts where little or no food challenge data are available.

Streamlining the analytical workflow for multiplex MS/MS allergen detection in processed foods

Allergenic ingredients in pre-packaged foods are regulated by EU legislation mandating their inclusion on labels. In order to protect allergic consumers, sensitive analytical methods are required for detect allergen traces in different food products. As a follow-up to our previous investigations, an optimized, sensitive, label-free LC-MS/MS method for multiplex detection of five allergenic ingredients in a processed food matrix is proposed. A cookie base was chosen as a complex food matrix and home-made cookies incurred with whole egg, skimmed milk, soy flour, ground hazelnut and ground peanut were prepared at laboratory scale. In order to improve the analytical workflow both protein extraction and purification protocols were optimized and finally a sensitive streamlined SRM based analytical method for allergens detection in incurred cookies was devised. The effect of baking on the detection of selected markers was also investigated.

Evaluation of Commercial Milk-Specific Lateral Flow Devices

The requirement for validation of allergen cleaning processes is increasing. The use of lateral flow devices (LFDs) to identify allergens has rapidly expanded, but the best practices for use of these devices are still developing. The goal of this study was to compare commercially available milk-specific LFDs and a general protein identification method. Five milk proteins and seven milk-derived ingredients were tested at several concentrations with eight milk-specific LFDs and a general protein identification kit. Nonfat dry milk (NFDM) was prepared at 100 to 10,000 ppm of milk protein and analyzed by the LFDs to determine the concentration at which a false-negative result (overload concentration or hook effect) was obtained. NFDM was also prepared in 0.025 M phosphate-buffered saline (pH 7.4, 0.85% NaCl) and applied to stainless steel panels (100, 30, 10, or 3 μg of NFDM protein) with various drying methods and sampled with various swab methods to determine the level of detectability. Several total milk LFD kits did not detect whey proteins or whey-derived ingredients. The overload concentration of the various kits ranged from 100 to 10,000 ppm of milk protein. The small dynamic range observed for some kits would necessitate multiple dilutions of a sample to ensure that the result would fall within the range of detection. For swab sampling of stainless steel for LFD analysis, milk protein residues from surfaces onto which the residues were dried with high heat were more difficult to detect than were residues dried with low heat. No differences in sensitivity were observed as a result of moistening the residue or the swab before sampling. These results highlight the importance of understanding the detection capabilities of LFDs as indicated by the variability in the performance of the milk-specific LFDs tested.

Food allergen detection by mass spectrometry: the role of systems biology

Food allergy prevalence is rising worldwide, motivating the development of assays that can sensitively and reliably detect trace amounts of allergens in manufactured food. Mass spectrometry (MS) is a promising alternative to commonly employed antibody-based assays owing to its ability to quantify multiple proteins in complex matrices with high sensitivity. In this review, we discuss a targeted MS workflow for the quantitation of allergenic protein in food products that employs selected reaction monitoring (SRM). We highlight the aspects of SRM method development unique to allergen quantitation and identify opportunities for simplifying the process. One promising avenue identified through a comprehensive survey of published MS literature is the use of proteotypic peptides, which are peptides whose presence appears robust to variations in food matrix, sample preparation protocol, and MS instrumentation. We conclude that proteotypic peptides exist for a subset of allergenic milk, egg, and peanut proteins. For less studied allergens such as soy, wheat, fish, shellfish, and tree nuts, we offer guidance and tools for peptide selection and specificity verification as part of an interactive web database, the Allergen Peptide Browser (http://www.AllergenPeptideBrowser.org). With ongoing improvements in MS instrumentation, analysis software, and strategies for targeted quantitation, we expect an increasing role of MS as an analytical tool for ensuring regulatory compliance.

Advances in ultra-high performance liquid chromatography coupled to tandem mass spectrometry for sensitive detection of several food allergens in complex and processed foodstuffs

Sensitive detection of food allergens is affected by food processing and foodstuff complexity. It is therefore a challenge to detect cross-contamination in food production that could endanger an allergic customer's life. Here we used ultra-high performance liquid chromatography coupled to tandem mass spectrometry for simultaneous detection of traces of milk (casein, whey protein), egg (yolk, white), soybean, and peanut allergens in different complex and/or heat-processed foodstuffs. The method is based on a single protocol (extraction, trypsin digestion, and purification) applicable to the different tested foodstuffs: chocolate, ice cream, tomato sauce, and processed cookies. The determined limits of quantitation, expressed in total milk, egg, peanut, or soy proteins (and not soluble proteins) per kilogram of food, are: 0.5mg/kg for milk (detection of caseins), 5mg/kg for milk (detection of whey), 2.5mg/kg for peanut, 5mg/kg for soy, 3.4mg/kg for egg (detection of egg white), and 30.8mg/kg for egg (detection of egg yolk). The main advantage is the ability of the method to detect four major food allergens simultaneously in processed and complex matrices with very high sensitivity and specificity.

Survey of undeclared soy allergen levels in the most frequently recalled food categories with or without precautionary labelling

A comprehensive study was designed to determine the frequency and levels of soy allergen in packaged bakery and snack food products. A representative sample of products with no soy allergen disclosed on the label was analysed using two widely used enzyme-linked immunosorbent assay (ELISA) methods. Samples were chosen that either had no soy identified on the product label or which had a soy precautionary statement. Among 558 bakery and snack products, soy protein was detected in 17% of the products using the Neogen (NE) kit and 11% of the products using the Elisa Systems (ES) kit. The disagreement rates between kits were 8.8% for bakery products and 3.3% for snack products. Overall soy protein was detected at higher frequency in bakery products than in snack foods. Among 284 bakery samples, soy protein was detected in 25% of the samples with no precautionary statement and 19% of the samples which had a precautionary statement. Among 274 snack samples, soy protein was detected in 11% of the samples with no precautionary statement and 9% of the samples which had a precautionary statement. The sample repeatability was at an acceptable level (< 9%) for each method and food commodity. The reproducibility between kits was 23% for bakery foods and 36% for snack foods. None of the bakery (21) and snack (6) products without precautionary labelling (measured level > 5 ppm) had a higher level of soy protein per serving compared with the eliciting dose10 (ED10) of 10.6 mg for soy allergic patients. But the level of soy protein per serving may be clinically relevant to a subpopulation of soy allergic patients if a more stringent eliciting dose is applied. These findings emphasise that suitable detection methodologies and references doses are crucial for labelling accuracy and the safety of soy allergic consumers.

Survey of undeclared egg allergen levels in the most frequently recalled food types (including products bearing precautionary labelling)

Since the number of recalls involving undeclared allergens is commonly associated with bakery and snack foods, we aimed to determine the frequency of egg allergens in a large number of these products using two commercial enzyme-linked immunosorbent assay (ELISA) methods. Samples were chosen that either had no egg identified on the product label or which had an egg precautionary statement. Among all samples, egg protein was detected in 5% of products using a Morinaga (MO) kit and 1% of products using a R-Biopharm (RB) kit. For bakery samples, egg protein was detected in 6% of 363 samples with no precautionary labelling (6% by MO and 1% by RB kit) and 12% of 80 samples which had precautionary labelling. For snack samples, egg protein was detected in 2% of 371 samples with no precautionary labelling (2% by MO and < 1% by RB kit) and 5% of 21 samples which had precautionary labelling. The disagreement rates between two methods were 5.2% for bakery products and 2.6% for snack products. The sample repeatability was at an acceptable level for bakery (< 12.5%) and snack foods (< 7.5%) for each method. The relative standard deviation between test kits was high (103.1%) for bakery foods. Four bakery products without precautionary labelling had a higher level of egg protein per serving compared with the eliciting dose (ED10 of 3.7 mg protein) for egg allergic patients. These results highlight the fact that detection methodology plays a vital role for accurate labelling control and mitigation of risk for egg allergic consumers.

Dietary management of peanut and tree nut allergy: what exactly should patients avoid?

Peanut and tree nut allergies are the commonest cause of life-threatening food-allergic reactions and significantly affect quality of life in children and their families. Dietary nut avoidance and provision of emergency medication is currently the mainstay of treatment. Nut avoidance has consequences on both quality of life and nutrition. We review the terminology that may cause confusion and lead to unnecessary dietary restrictions. In peanut or tree nut-allergic children, introduction of specific nuts to which the child is not allergic may improve quality of life and should be considered in patients with multiple foods allergies, vegan or ethnic-specific diets, in whom nuts are an important source of protein. Nut-allergic consumers do not just need to avoid foods containing nuts as an ingredient, but also contend with pre-packed foods which frequently have precautionary allergen labelling (PAL) referring to possible nut contamination. Although the published rate of peanut contamination in 'snack' foods with PAL (see Box ) ranges from 0.9-32.4%, peanut contamination in non-snack items with PAL is far less common. We propose that in some peanut-allergic patients (depending on history of reactivity to trace levels of peanut, reaction severity, other medical conditions, willingness to always carry adrenaline, etc.), consideration may be given to allow the consumption of non-snack foods containing PAL following discussion with the patient's (and their family's) specialist. More work is needed to provide consumers with clearer information on the risk of potential nut contamination in pre-packed food. We also draw attention to the change in legislation in December 2014 that require mandatory disclosure of allergens in non-pre-packed foods.

Recent Advances in Management of Pediatric Food Allergy

Many children now suffer with a food allergy, immunoglobulin E (IgE) and/or non-IgE mediated. Food allergies have a significant impact on the child’s quality of life, as well as that of their family, due to the resultant dietary restrictions and the constant threat of a potentially life-threatening reaction. At present, there is no cure for food allergies, but there are exciting advances occurring in the management of IgE mediated allergies, including a more active approach to management with anticipatory screening testing, early introduction of common food allergens, active tolerance induction, use of biologics and active risk management. These areas will be discussed in this review.

Frequency, severity and causes of unexpected allergic reactions to food: a systematic literature review

Food allergic patients have to deal with an avoidance diet. Confusing labelling terms or precautionary labels can result in misinterpretation and risk-taking behaviour. Even those patients that strictly adhere to their diet experience (sometimes severe) unexpected allergic reactions to food. The frequency, severity and causes of such reactions are unknown. The objective of this review was to describe the frequency, severity and causes of unexpected allergic reactions to food in food allergic patients aged > 12 years, in order to develop improved strategies to deal with their allergy. A systematic review was carried out by two researchers, in six electronic databases (CINAHL, Cochrane, EMBASE, Medline, Psychinfo and Scopus). The search was performed with keywords relating to the frequency, severity and causes of unexpected allergic reactions to food. This resulted in 24 studies which met the inclusion criteria; 18 observational and six qualitative studies. This review shows that knowledge about the frequency of unexpected reactions is limited. Peanut, nuts, egg, fruit/vegetables and milk are the main causal foods. Severe reactions and even fatalities occur. Most reactions take place at home, but a significant number also take place when eating at friends' houses or in restaurants. Labelling issues, but also attitude and risky behaviour of patients can attribute to unexpected reactions. We conclude that prospective studies are needed to get more insight in the frequency, severity, quantity of unintended allergen ingested and causes of unexpected allergic reactions to food, to be able to optimize strategies to support patients in dealing with their food allergy. Although the exact frequency is not known, unexpected reactions to food occur in a significant number of patients and can be severe. For clinical practice, this means that patient education and dietary instructions are necessary.

Precautionary allergen labelling: perspectives from key stakeholder groups

Precautionary allergen labelling (PAL) was introduced by the food industry to help manage and communicate the possibility of reaction from the unintended presence of allergens in foods. However, in its current form, PAL is counterproductive for consumers with food allergies. This review aims to summarize the perspectives of all the key stakeholders (including clinicians, patients, food industry and regulators), with the aim of defining common health protection and risk minimization goals. The lack of agreed reference doses has resulted in inconsistent application of PAL by the food industry and in levels of contamination that prompt withdrawal action by enforcement officers. So there is a poor relationship between the presence or absence of PAL and actual reaction risk. This has led to a loss of trust in PAL, reducing the ability of consumers with food allergies to make informed choices. The result has been reduced avoidance, reduced quality of life and increased risk-taking by consumers who often ignore PAL. All contributing stakeholders agree that PAL must reflect actual risk. PAL should be transparent and consistent with rules underpinning decision-making process being communicated clearly to all stakeholders. The use of PAL should indicate the possible, unintended presence of an allergen in a consumed portion of a food product at or above any proposed action level. This will require combined work by all stakeholders to ensure everyone understands the approach and its limitations. Consumers with food allergy then need to be educated to undertake individualized risk assessments in relation to any PAL present.

Detection of the peanut allergen Ara h 6 in foodstuffs using a voltammetric biosensing approach

A voltammetric biosensor for Ara h 6 (a peanut allergen) detection in food samples was developed. Gold nanoparticle-modified screen-printed carbon electrodes were used to develop a sandwich-type immunoassay using two-monoclonal antibodies. The antibody-antigen interaction was detected through the electrochemical detection of enzymatically deposited silver. The immunosensor presented a linear range between 1 and 100 ng/ml, as well as high precision (inter-day RSD ≤9.8%) and accuracy (recoveries ≥96.7%). The detection and quantification limits were 0.27 and 0.88 ng/ml, respectively. It was possible to detect small levels of Ara h 6 in complex food matrices.

Unintended allergens in precautionary labelled and unlabelled products pose significant risks to UK allergic consumers

BACKGROUND

Allergens in food may pose a risk to allergic consumers. While there is EU regulation for allergens present as an ingredient, this is not the case for unintended allergen presence (UAP). Food companies use precautionary allergen labels to inform allergic individuals of a potential risk from UAPs. This study investigates the risk of an allergic reaction within the milk-, wheat-, hazelnut- and peanut-allergic populations when ingesting UK foods across multiple product categories with and without precautionary allergen labelling.

METHODS

Allergen risk assessment using probabilistic techniques enables the estimation of the residual risk after the consumption of a product that unintentionally contains an allergen.

RESULTS

Within this selection of UK products, the majority that tested positive for an allergen contained a concentration of allergen predicted to cause a reaction in >1% of the allergic population. The concentrations of allergens measured were greater than the VITAL(®) 2.0 action levels and would trigger precautionary allergen labelling. This was found for products both with and without precautionary allergen labelling.

CONCLUSIONS

The results highlight the need for the food industry and regulators to adopt a transparent, risk-based approach for the communication of the risk associated with potential cross-contact that could occur in the processing facility or production chain.