James, Christopher Adam
(2025)
Current and emergent allergens in food production systems.
PhD thesis, University of Nottingham.
Abstract
Of the global population, around 10% has a form of food allergy, with exposure to allergens in foods driving a variety of symptoms ranging from urticaria, localised swelling, discomfort, through to anaphylaxis. Incidence of food allergy has been identified to be increasing year on year, in relation to changes to the modern lifestyle leading to further diet diversity within in global populations, with greater exposure to and consumption of allergenic foods. Commonly, food allergens have been found to have current routes of exposure through unintended food allergen contamination in food production systems and the mislabelling of products, this resulting in frequent product recalls worldwide. The work presented in this thesis builds on current knowledge and explores emergent routes of food allergen exposure in the general population with a view of the expansion of ingredients used by the food industry and purchased online from digital food systems. Importantly, issues surrounding food allergy have the capacity to continue to increase over the next few decades due to the advent of circular agrifood economies and further incorporation of emerging foods with the potential for allergenicity to facilitate development of more sustainable food production systems. Three key areas became the focus of the current work 1) Emergent foods as sources of allergens in the human food chain, 2) Routes of food allergen transmission and exposure via new purchasing routes i.e. purchasing through online food systems and 3) The potential of allergen retention by food contact and storage materials as a possible route of allergenicity. Combined, our research sets the foundations for future work in these areas.
The main findings of the current research identify that current and emergent food allergens are potentially increasing within modern food production systems and due to being unintended or undeclared have the capacity to pose a risk to consumers with food allergy. We first assessed, macro- and microalgal derived products as emergent food sources, as current drives to increase their incorporation into foods are gaining greater attention. We reported that edible algal species (microalgae: Arthrospira and Chlorella species; macroalgae: Chondrus crispus, Palmaria palmata and carrageenan isolated from several sources including Chondrus crispus, Eucheuma and Gigartina species), widely cultivated globally, are potential sources of emergent allergens in modern food production systems. Several allergenic components have been characterised, and these have been shown to induce allergic responses in humans. It was also reported that algal products have the potential to act as a vector of current food allergens including fish and shellfish. We next focused on a land growing crop, namely kiwifruit (Actinidia species) that is becoming more widely grown globally and incorporated into a spectrum of differing food items. The prevalence of a variety of food allergy reactions to kiwifruit has been identified globally (0-18 yrs: 0.1-0.2% to 60.0%; >18-96 yrs: 0.35% to 38.4%) and various proteinaceous kiwifruit allergens have been characterised namely actinidin/cysteine protease (Act d 1/Act c 1), thaumatin-like protein (Act d 2) and kiwellin (Act d 5/Act c 5). Food allergens from kiwifruit have been found to demonstrate cross-reactivity with other fruit and plant allergens and are often resistant to processing methods. In recent times, use of kiwifruit is increasing in processed products, including snacks, desserts, confectionary, condiments, beverages and food additives or functional ingredients (e.g. colours, flavours or coagulants), within food production systems, which could introduce the risk of its consumption as an unintended or unidentified food allergen.
In our remaining chapters, we focused on routes of exposure from digital food systems and stability of food allergens in commercial washing processes. Online purchasing has increased in recent years, with recent reports describing that 60.8% of UK consumers are buying groceries online, and so we designed a series of experiments to capture transmission of current allergens in foods purchased via internet sources. We randomly selected 768 prepacked imported products purchased online and following extensive screening identified that 173 (22.5%) items provided precautionary allergen labelling and upon comparing food allergen information on pack and online, found that 36 (36.0%) transferred inconsistencies on pack to online pages and 15 (15.0%) were not consistent between information on pack and online. We also conducted a sub-analysis of the online purchased items including 77 products and assessed the unintended food allergen presence of milk and peanut using biochemical (ELISA) methodologies. Following analysis for milk and peanut via ELISA, 24 (31.2%) products were found to contain unintended food allergens, with 7 (29.2%) having levels that would recommend precautionary allergen labelling, though this was not present on these products to communicate this risk to consumers with food allergy. Clearly, this work points to significant avenues of allergen exposure via foods obtained through online sources and more work is needed in this area.
Our final study explored an additional route of allergen exposure via retention of food allergens to common materials used to produce food contact and storage materials. Using sesame as a model allergen analyte, we designed and validated a novel methodology to assess impacts of soiling on food allergen retention on surfaces. After applying current commercial warewashing procedures it was found that, all studied materials (glass, lacquered metal and polypropylene plastic) retained varying amounts of food allergen soil, despite appearing visually clean, and warewashers can readily transfer food allergens to subsequent wash cycles and onto food contact surfaces in them. Analytical results obtained using an ELISA method were compared to action levels, identifying that minimum or maximum levels for products contained in all container types post-washing presented potential health risks to consumers with food allergy.
In summary, the results of this thesis indicate the need for the further assessment of current and emergent sources of food allergens that are increasing within modern rapidly developing food production systems, their incidence of being unintended or undeclared and potential to pose a food safety risk to consumers with food allergy. In addition to this, more work is required to understand the food safety risks of emergent food products demonstrating allergenicity and methods to better manage and communicate the risks of both current and emergent food allergens.
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