Corn and peanut oil (total, 253 samples) were collected from 32 households in Fushui county of the Guangxi autonomous region of the People's Republic of China, where high liver cancer incidence has been reported, every day over a period of 1 week and analyzed for aflatoxin B1 (AFB). A total of 252 urine samples were collected simultaneously from the residents in the households which were shown to have consumed AFB and were analyzed for aflatoxin M1 (AFM) by a competitive direct enzyme-linked immunosorbent assay. A good correlation between total dietary AFB intake and total AFM excretion in human urine was observed during a 3-day study. A regression equation of 0.143 plus 0.0135 multiplied by the amount of AFB consumed was observed. Between 1.23 and 2.18% of dietary AFB was found to be present as AFM in human urine. A good correlation was also observed between the AFB concentration in corn and the AFM concentration in human urine. The results suggest that analysis of AFM in urine by enzyme-linked immunosorbent assay could be used as an index for human exposure of AFB in an extensive epidemiological study.
This work was supported by the College of Agricultural and Life Sciences and the graduate school of the University of Wisconsin at Madison, by USPHS Grant CA-15064 from the National Cancer Institute, and by a research grant [to F. S. C.] from the National Program for Advanced Study and Research in China of the Committee on Scholarly Communication with the People's Republic of China of the National Science Foundation. The authors also acknowledge the financial support [to J-q. Z. and J-s. C.] for sample collection from the Boston University Biomedical Research Committee (Grant 2-S07-RR0592) and the American Cancer Society (Grant SIG-10-I, also to Boston University).