Citreoviridin levels in Eupenicillium ochrosalmoneum-infested maize kernels at harvest.

Citreoviridin contents were measured in eight bulk samples of maize kernels collected from eight fields immediately following harvest in southern Georgia. Citreoviridin contamination in six of the bulk samples ranged from 19 to 2,790 JJ.g1kg. In hand-picked samples the toxin was concentrated in a few kernels (pick-outs), the contents of which were stained a bright lemon yellow (range, 53,800 to 759,900 JJ.g/kg). The citreoviridin­ producing fungus Eupenicillililn oclzrosalmoneum Scott & Stolk was isolated from each of these pick-out kernels. Citreoviridin was not detected in bulk samples from two of the fields. Aflatoxins were also present in all of the bulk samples (total aflatoxin B1 and B2 ; range, 7 to 360 JJ.g/kg), including those not containing citreoviridin. In Biotron-grown maize ears that were inoculated with E. oclzrosalmonellm through a wound made with a toothpick, citreoviridin was concentrated primarily in the wounded and fungus-rotted kernels (range, 142,000 to 2,780,000 JJ.g/kg). Samples of uninjured kernels immediately adjacent to the wounded kernel (first circle) had less than 4,000 JJ.g of citreoviridin per kg, while the mean concentration of toxin in kernel samples representing the next row removed (second circle) and all remaining kernels from the ear was less than 45 JJ.g/kg. Animal toxicosis has not been linked to citreoviridin-contaminated maize. The discovery that Eupenicillium ochrosalmoneum Scott & Stolk infests preharvest maize and contaminates the damaged kernels with the neurotoxic mycotoxin citreoviri­ din (7, 8) required that we learn more about the distribution and amounts of the toxin in maize ears. Citreoviridin is thought to be the toxin responsible for the disease acute cardiac beriberi that has prevailed in Japan and Asia and that is associated with the consumption of molded and yellowed rice (6). There are no reported animal mycotoxicoses linked to the consumption of citreoviridin-contaminated maize. However, maize meal inoculated with citreoviridin-pro­ ducing strains of Penicillium pulvillorum Turntt and fed to day-old ducklings caused acute poisoning of these test animals (5). The development of an accurate quantitative method for determining levels of citreoviridin in maize kernels (R. D. Stubblefield, J. 1. Greer, and O. L. Shotwell, J. Assoc. Off. Anal. Chern., in press) enabled us to analyze naturally contaminated maize kernels for citreoviridin. In addition, we examined the distribution of citreoviridin in maize ears that were produced in a controlled environment and wound inoculated with E. ochrosalmoneum.