An In-vitro Assessment of the Genotoxic Potential of In-Shell Nut Ingredients According to OECD Genotoxicity Guidelines 471 and 487

Aims: In vitro genotoxicity of three shell-comprising nut ingredients, i.e., Almond Solids from roasted in-shell Almonds (Almond Solids), Almond Liquid Extract from roasted in-shell Almonds (Almond Liquid Extract) and Peanut Paste from roasted in-shell Peanuts (Peanut Paste) was assessed. Study Design: Genotoxic safety was evaluated by performing two standard genotoxicity tests according to OECD 471 (the bacterial reverse mutation assay) and OECD 487 (the in vitro mammalian cell micronucleus test) Place and Duration of Study: OECD 471 assays were performed in 2025 at Toxi-Coop Zrt., Balatonfüred, Hungary and at Charles River Laboratories, DD’s-Hertogenbosch, The Netherlands. OECD 487 assays were performed in 2025 at Eurofins Munich, Planegg, Germany. Methodology: All assays were conducted in accordance with internationally recognized OECD Test Guidelines 471 and 487 and complied with the principles of Good Laboratory Practice (GLP). Results: The test results showed that neither Almond Solids nor Peanut Paste at 1.6-5000 μg/plate nor Almond Liquid Extract at 52-5000 μg/plate induced significant bacterial reverse mutations in Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537 and in Escherichia coli strain WP2uvrA, both in the presence and absence of a metabolic activation system. The in vitro micronucleus assays using human lymphocytes, performed on Almond Solids at 250-1500 μg/mL, Almond Liquid Extract at 78.15-1250 μg/mL and Peanut Paste at 50-200 μg/mL were all negative for genotoxicity, with no increases in micronucleated cells frequency, either with or without metabolic activation. Conclusion: Under the experimental conditions used, negative results in the genotoxicity assays support the good safety profile of Almond Solids, Almond Liquid Extract and Peanut Paste. These three shell-comprising nut ingredients can thus be considered not to be of genotoxic concern. These studies lay the foundation for future toxicological evaluations of ingredients based on nutshells.