Isolation of Fusarium species from some food and feed and prevention of their growth by irradiation.

Abstract

Seventy samples of different cereal grains, garlic, onion and animal feed were collected from the Egyptian markets to isolate associated moulds. Fusarium, Aspergillus, Penicillium and Rhizopus were the most common fungal genera isolated from the different samples. The genus Fusarium was the most dominant among the fungal genera and all isolates were identified as F. verticillioides, F. solani, F. oxysporum, F. dimerum, F. tabacinum and F. xylaroides. Fusarium verticillioides and F. solani were the most dominant comprising 58% of the total isolates. All Fusarium isolates were proved to produce one or more of zearalenone, diacetoxyscirpenol and fusaric acids in liquid medium. Irradiation at a dose of 5 KGy reduced the Fusarium growth greatly relative to non-irradiated controls. On the basis of the radiation survival data, the radiation decimal reduction doses (D10 values) for F. oxysporum, F. solani, F. verticillioides and F. dimerum were 1.44, 1.66, 1.73 and 1.00 KGy in corn, respectively. Application of radiation at a dose of 12.5 KGy made corn samples free from mould throughout all the storage period (12 weeks) and there was no fungal growth and no mycotoxins have been produced.