Aflatoxins are fungi secondary metabolites that contaminate cereals and other products of vegetable origin. Aflatoxin B₁ (AFB₁) is the most common and the most toxic aflatoxin. After the ingestion of AFB₁ contaminated feeds, a part is degraded in the rumen, resulting in the formation of aflatoxicol. The remaining fraction is absorbed in the digestive tract by passive diffusion and is hydroxylated in the liver to aflatoxin M₁ (AFM₁). Circulating AFM₁ can be excreted in the urine or appear in milk. AFM₁ excretion is also observed in human milk. AFM₁ was originally classified as a Group 2B – possibly carcinogenic to humans, in 1993, but subsequent evidence of its cytotoxic, genotoxic and carcinogenic effects led to a new categorization of AFM₁ as Group 1. The occurrence of aflatoxin M₁ (AFM₁) was evaluated in 42 milk (pasteurized, ultra-high treated (UHT) milk and milk powder) randomly collected in July 2014 from supermarkets in Londrina, Paraná State, Brazil and this rate of occurrence was used to estimate AFM₁ exposure. AFM₁ determination was carried out by ELISA. AFM₁ was detected in 100% samples, with levels ranging from 0.01 to 0.81 µg/kg, and a mean of 0.13 µg/kg. Differences were observed in AFM₁ levels in milk powder samples (0.61 µg/kg) compared with pasteurized (0.02 µg/kg) and UHT milk (0.04 µg/kg; P < 0.05). None of the samples presented AFM₁ above the maximum permitted level by Brazilian Legislation (0.5 µg/kg for fluid milk and 5 µg/kg for milk powder). Determination of the exposure degree is one of the most important parameters to assess risk from chemical compounds. The Estimated Daily Intake (EDI) of AFM₁ from fluid milk and milk powder was obtained using the amount of food consumed and the corresponding mean concentrations of AFM₁ detected in each food group, taking into account the mean body weight of the age groups. The estimated daily intake (EDI) of AFM₁ was evaluated, and the average intake was 0.468 ng/kg body weight (BW) for adolescents, 0.384 ng/kg BW for adults and 0.559 ng/kg BW for the elderly, values that pose a toxicological risk to the population investigated.