Occurrence and Control of Alternaria alternata, Penicilliun citrinum and Aspergillus flavus Mycotoxins in Broad Bean Seeds by Benzoic and Sorbic Acids

Abstract

Infected broad bean seeds were collected from Noubaria region during the season 2017-2018. Fungi isolated and purified from collected seeds were identified as Aspergillus flavus, Penicilliun citrinum and Alternaria alternata. The occurrence frequencies of the isolated fungi were 9.08, 15.16 and 75.76 %, respectively. Production potentials oftoxin by Alternaria alternata and P. citrinum isolates, as estimated by the Plug Agar method, were 23100 and 33700 ng/g, respectively. Production of aflatoxins by A. flavus isolates not detected. Sorbic and benzoic acids were showed to be more effective in reducing the growth of A. alternata and P. citrinum than metalaxyl and ridomyl fungicides. A. alternata was less sensitive to sorbic acid than benzoic acid. All the tested treatments significantly reduced the growth of A. alternata growth and alternariol (AOH) production; however, a higher efficiency ratio (99.86%) was realized by benzoic acid. Similar inhibition of growth and citrinin (CTN) production was found on P. citrinum. Metalaxyl was less efficient in inhibiting AOH and CTN toxins than the other tested treatments. The efficiency of benzoic and sorbic acids to reduce AOH and CTN production was higher by soaking seed treatment. Seeds inoculated with the tested fungi, then treated with sorbic or benzoic acid found to be healthy with normal color, texture and morphology.