Corn is one of the most cultivated cereals in Brazil. However, its grains are constantly exposed to contamination by mycotoxins. Corn grits are used by the food industry to produce a large variety of corn products such as canjiquinha, a cultural food easily purchased by the Brazilian consumer at low prices. Some studies have demonstrated high contamination of this product by aflatoxins (AFs), representing a potential risk of exposure due to such a contamination. In this study, the efficacy of gaseous ozonation was evaluated on the levels of aflatoxins and on the microbial contamination of corn grits. The application of gaseous ozone was tested in different combinations of exposure time, ozone concentration, and canjiquinha mass. After the ozonation treatment, samples were collected for aflatoxin and microbiological analyses. Aflatoxins were evaluated using a high-performance liquid chromatography with fluorescence detection (HPLC-FD) system using pre-column derivatization, and the microbiological analyses were carried out for toxin-producer fungi and mesophilic bacteria. After ozone detoxification, results showed reductions up to 57% in aflatoxin levels. Total fungal count was reduced around 3.0 cycles log CFU g⁻¹ and total mesophilic counts were reduced to non-detectable levels. These results demonstrated that ozonation is an effective alternative for reducing aflatoxin and microbial contamination in products like canjiquinha, thereby improving food safety.