A preliminary survey on aflatoxin exposure in Singapore

Aflatoxins (naturally occurring chemicals of fungal origin) are powerful liver carcinogens, and increased incidence of hepatocellular carcinoma has been observed in areas where exposure to this mycotoxin is high (e.g., Africa, China). These areas also have a high incidence of HBV infection. It has been suggested that this environmental carcinogen interact with HBV in the aetiogenesis of hepatocellular carcinoma in these areas. The aim of this study was to determine the level of aflatoxin exposure in the local population. Fifty healthy adults were studied. Details of dinner taken the previous evening were obtained. Early morning urine was collected and aflatoxin quantitated by ELISA following purification on an antibody affinity column. Rabbit polyclonal antibody to aflatoxin B1 was used, and the mean of at least two assays were determined. Six individuals (12%) showed ELISA inhibition values of more than 25%, equivalent to aflatoxin levels of more than 100 pg/ml in urine. Levels ranged from 185 pg/ml to 2300 pg/ml aflatoxin B1 equivalents. All 6 individuals consumed fried food. The highest level was found in a medical student who had 'satay' (crushed peanut) sauce with dinner. This is in contrast to 52% individuals from Gambia with urine aflatoxin levels between 100 and 1000 pg/ml.