Food safety of insect and microalgae alternative proteins: IgE cross-reactivity and cytotoxicity evaluation

ABSTRACT Edible insects and microalgae are gaining increasing attention as sustainable alternative protein sources due to their high nutritional value and low environmental impact. However, the introduction into human and animal diets requires careful safety evaluation particularly regarding allergenic potential and possible cytotoxic effects. In this study, we assessed the cytotoxicity and IgE cross-reactivity of proteins derived from two insect species, Tenebrio molitor and Ceratitis capitata , and two microalgae species, Chlorella vulgaris and Galdieria sulphuraria . Cytotoxicity was evaluated in dose–response experiments using different fractions obtained from insect and microalgae samples on Caco-2 cell cultures. IgE cross-reactivity was investigated using sera from 48 adult patients with pre-existing allergies to dust mites, crustaceans, or both. The results showed that sera from individuals sensitized to highly conserved allergenic proteins, such as tropomyosin and arginine kinase, displayed IgE reactivity toward the protein extracts from the tested novel foods. This suggests that sequence similarities among allergenic proteins across species may lead to cross-reactive responses, potentially triggering allergic reactions in sensitized individuals. Cytotoxicity assays revealed no significant effects associated with the protein fractions, whereas hydroalcoholic extracts showed indications of potential cytotoxic activity. Overall, these findings highlight the importance of evaluating the allergenic potential of insects and microalgae as emerging protein sources, particularly for individuals sensitized to arthropods or related allergens. Furthermore, the characterization of different sample fractions and their cytotoxicity profiles may support the development of safer processing strategies for these novel food and feed ingredients.