Occurrence and factors associated with the presence of aflatoxin M1 in breast milk samples of nursing mothers in central Mexico

- AFM1 was detected in 89% of breast milk samples assessed.
- The concentration of AFM1 found in the samples was in the range of 3.01-34.24 ng/L.
- AFM1 was significantly associated to egg, cola drink and sunflower seed oil consumption.
- Estimated daily intake of AFM1 exceeded the tolerable values for these mycotoxins.
- This is the first report of AFM1 in breast milk of Mexican nursing mothers.

Aflatoxin M1 (AFM1) is the main mycotoxin frequently found in milk and dairy products. Exposure of infants to AFM1 is of great health public concern because of its toxic and carcinogenic properties. The aim of this study was to determine the occurrence, levels and factors associated with the presence of aflatoxin M1 in breast milk samples of nursing mothers in central Mexico. A total of 112 samples were collected and analyzed by a competitive-ELISA assay during January-August 2014. A Semi-Quantitative Food Frequency Questionnaire was used to determine weekly intake of food groups. Results showed that 89% of breast milk samples contained AFM1 in a range of 3.01-34.24 ng/L. AFM1 mean level was significantly higher (P < 0.05) in winter (12.78 ng/L) and spring (12.09 ng/L) than summer (7.91 ng/L). It was also detected that 7% of samples exceeded the European Community regulation (25 ng/L) for milk infant formula. The presence of aflatoxin M1 was significantly associated (P < 0.05) to consumption of egg, cola drink and sunflower oil. The high occurrence and noticeable levels of AFM1 detected, as well as the mean AFM1 estimated daily intake (2.35 ng/kg b.w./day) suggested, for the first time, that breast-fed infants in the central region of Mexico, may be exposed to significant levels of this toxin through mother's breast milk.