Occurrence of Genotoxic Furan-2(5 H )-one in Heated Milk and Pancakes: Key Role of Lactose and Free Radicals during Cooking

Abstract

Furan-2(5H)-one is a genotoxic α,β-unsaturated lactone occurring naturally in heat-processed foods. Its formation pathways in food systems remain poorly understood. This study combines analyses of commercial milks and model systems to evidence which factors influence their synthesis, with a special focus on furfuryl alcohol as the key intermediate. Although the threshold of toxicological concern for furan-2(5H)-one is 0.15 μg person−1·day−1, growing-up cow milks and chocolate drinks were found to contain up to 383 and 521 μg·kg−1, respectively, versus <50 μg·kg−1 in soy-based alternatives. Under severe heating conditions (133 °C, 20 min), furan-2(5H)-one levels reached 5741 μg·kg−1 in cow milk, significantly exceeding the levels measured in lactose-free milk (266 μg·kg−1). Pancakes prepared with lactose-containing milk similarly exhibited substantially higher concentrations (650 μg·kg−1) than their lactose-free counterparts (26 μg·kg−1). Results obtained with aqueous model systems demonstrated the pivotal role of disaccharides and Fenton reagents in furan-2(5H)-one formation. Our data raise concerns regarding the occurrence of this compound in other thermally processed foods.