Inhibition of Patulin Production with the Insecticide Naled

Abstract

Patulin is a wide spectrum biocide produced by several species of Aspergillus, Penicillium and Byssochlamys, and is a potentially important mycotoxin that may be ingested by man. The effect of the insecticide naled on fungal growth and patulin production was evaluated using three concentrations (1, 10, and 100 mg/l, ppm) and several application times both before inoculation and during growth of the fungus. If added before inoculation, naled at 100 mg/l completely inhibited mycelial growth of Penicillium urticae for 15 days and patulin production for 30 days. When the concentration was decreased to 10 mg/l, and the insecticide added at the time of inoculation, patulin production was inhibited by 59%. If 100 mg of naled/1 was added between 3 and 6 days after fungal growth was visible, patulin production was inhibited by more than 50%. If the insecticide was added at this same concentration to cultures older than 6 days, patulin production was inhibited by 25–35%. Production of patulin in apples was inhibited by 76% and tissue damage inhibited by 43% when 100 mg of naled/1 was applied to apples before their inoculation and storage at 25 C. Naled was highly effective in inhibiting patulin production and showed long-term activity. However, naled completely inhibited patulin production only when applied before growth of the fungus.