Inactivation of aflatoxigenic fungi and the reduction of aflatoxin B1 in vitro and in situ using gamma irradiation

- Effect of gamma irradiation on aflatoxigenic moulds AFB1 level was tested.
- Gamma irradiation effectively stopped moulds' germination, sporulation and growth.
- Level of AFB1 in maize and feed samples was reduced by gamma irradiation.
- Gamma irradiation can be used to control AFB1 level in various commodities.

Detailed investigation on the effect of gamma (γ) irradiation on germination, sporulation, and growth of aflatoxigenic moulds (Aspergillus parasiticus 2999, Aspergillus flavus 305, and Aspergillus niger 388), as well as on the reduction of aflatoxin B1 (AFB1) level in artificially and naturally contaminated maize/feed samples was performed. The results of in vitro and in situ experiments with aflatoxigenic moulds demonstrated that 5 kGy-γ irradiation manages to prevent sporulation, germination and growth of the tested moulds both when in form of a pure and when in form of a mixed culture. In the feed samples artificially contaminated with AFB1 (50 μg kg−1) 5 kGy-γ irradiation reduced AFB1 level by around 60%, while 10 kGy-dose reduce it for around 85%. Similarly, in feed samples spiked with AFB1 in the concentrations of 100 μg kg−1 5 kGy-dose reduced the AFB1 level by approximately 70%, while the dose of 10 kGy reduced it by approximately 90%. The experiments on naturally contaminated maize samples (n = 30) confirmed these observations; following a 5 kGy-irradiation, the overall mean AFB1 reduction equalled to 69.8%, while the irradiation with a 10 kGy-dose achieved the overall mean toxin reduction of 94.5%. The obtained results indicate that γ irradiation can be used to prevent the growth of aflatoxigenic moulds and to reduce the AFB1 levels in various goods intended for animal and human consumption, thus minimizing the animal and human exposure to this carcinogenic mycotoxin.