Fluorodensitometric assay of penicillic acid.

Penicillic acid, a secondary metabolite first isolated from Penicillium puberuluml, has since been shown to be produced by a variety of fungi. The compound possesses antimicrobial activity2,3, is toxic to mammals4 , and has proved carcinogenic to rats5• KURTZMAN AND CIEGLER6 found that in blue-eye-diseased com caused by Penicillium martensii, large quantities of penicillic acid are produced when high-moisture com is stored at low temperatures (5 to 10°). Since blue-dye disease may be common in combine harvested corn, penicillic acid represents a potential mycotoxin hazard to humans and livestock. The colorimetric methods to detect this compound7,s lack the sensitivity required for a mycotoxin assay, the smallest detectable amount being 200 flg. We found that the product of the reaction between penicillic acid and ammonia fluoresced an intense blue and that this property could be used as the basis for a sensitive fluorodensitometric assay.