Exposure to aflatoxin B1 in animal-feed production plant workers.

The exposure to aflatoxin B1 (AFB) in animal-feed processing plants was assessed using binding of AFB to serum albumin. The albumin fraction was digested with pronase, and the digest was purified on a C18 Sepak column and an aflatest affinity column before quantification by ELISA. The level of detectability was 5 pg/mg albumin. The workers served as their own controls, as blood samples were taken upon return from vacation and after 4 weeks of work. A total of 7 of 45 samples were positive for AFB, with an estimated average daily intake of 64 ng AFB/kg body weight. The exposed workers had been disembarking cargos contaminated with AFB or working at places where the dust contained detectable amounts of AFB. The sera from the exposed workers had a significantly higher titer against an aflatoxin B1-epitope than a nonexposed Danish control group. The level of exposure could partly explain the increased risk of liver cancer in workers in the animal-feed processing industry.