4-Methylbenzophenone and benzophenone are inactive in the micronucleus assay

Many materials in contact with food, including printing inks, the lack of deeper knowledge about possible toxic effects is a problem. Furthermore, some of these substances are not only produced for packaging of foods, they are produced for a variety of purposes and are not meant to come into direct contact with foodstuffs. Two examples on such chemicals in printing inks are benzophenone and 4-methylbenzophenone. Recently, authorities reported that high levels of the photoinitiator 4-methylbenzophenone had been detected in cereal products. Based on this information we have studied 4-methylbenzophenone and the chemically similar benzophenone using the micronucleus assay in vivo and in vitro. To increase the sensitivity we have used the in vivo flow cytomer-based micronucleus assay in mouse.Although doses up to lethality were used and an average of hundred thousand young erythrocytes, polychromatic erythrocytes, analysed from each animal, no genotoxic effect occurred. The 4-methylbenzophenone was also analysed in the in vitro micronucleus assay, using human lymphocytes. The result does not show any dose-related effect.These results show that the occurrence of 4-methylbenzophenone that so far has been detected in foodstuff does not increase the cancer risk through chromosome breaks or mal-distribution of chromosomes.