Biological clues to potent DNA-damaging activities in food and flavoring

► We used a cellular biological (p53R) assay to screen for DNA-damaging activity in selected foods and flavorings. ► Potent DNA-damaging activity was seen in tea, coffee, and liquid smoke at concentrations consumed dietarily. ► DNA double-strand breaks were confirmed by the comet assay and immunoblots reporting H2AX phosphorylation. ► Pyrogallol-like substances are likely to be a major source of genotoxic activity in food and flavoring. ► These findings have implications for evaluation of dietary risks in epidemiologic studies and in designing safer diets.