Aflatoxin M1 and Ochratoxin A exposure via breast milk and potential risks in HIV-exposed and HIV-unexposed infants from Harare, Zimbabwe

The exposure of breastfeeding mothers to Aflatoxin B 1 and Ochratoxin A (OTA) via contaminated foods may expose infants to potentially genotoxic and carcinogenic Aflatoxin M 1 (AFM 1 ) and OTA via breast milk (BM). We conducted a retrospective cross-sectional substudy nested within a case-control cohort to assess the potential genotoxic and carcinogenic risks of AFM 1 and OTA exposure via BM consumption in six-week-old HIV-exposed-infected (HEI), HIV-exposed-uninfected (HEU) and HIV-unexposed-uninfected (HUU) infants from Harare, Zimbabwe. The AFM 1 and OTA concentrations in BM measured via ELISA were used to determine the median probable daily intake (MPDI) and margin of exposure (MOE) for the toxins. We included 5 HEI, 124 HEU and 133 HUU infants. Among HEI infants, 2/5 (40%) consumed AFM 1 (pg/ml) (median: 6.50; range: 6.44-6.55), whereas 0/5 (0%) consumed OTA via BM. Among HEU infants, 26/105 (25%) consumed AFM 1 (pg/ml) (median: 7.35; range: 5.96-29.8), whereas 11/124 (9%) consumed OTA (ng/ml) (median: 0.20; range: 0.14-0.65) via BM. Among HUU infants, 38/116 (33%) consumed AFM 1 (pg/ml) (median: 7.70; range: 6.07-31.75), whereas 4/133 (3%) consumed OTA (ng/ml) (median: 0.24; range: 0.18-0.83) via BM. BM consumed by the infants contained AFM 1 at levels exceeding 2.5 pg/ml, the European Union limit for the toxin in traded infant foods. The MPDIs of AFM 1 (ng/kg BW per day) in HEI, HEU and HUU infants were 1.02, 1.30 and 1.19, respectively. The MPDIs of OTA (ng/kg BW per day) in HEU and HUU infants were 30.20 and 42.55, respectively. In all infants exposed to AFM 1 and OTA, the MOE was <10,000 indicating exposure at levels that are potentially genotoxic and carcinogenic. The exposure of breastfeeding mothers to mycotoxins should be minimised to protect vulnerable infants.