Resumo

The sunflower (Helianthus annuus L.) currently occupies one of the first places in the world hierarchy of seed, the grain is of great value because it is a rich source of protein used in animal feed, edible oil production and of flour that serve as ingredient for the production of bread and other whole foods. Care in storage, humidity and temperature control, assist in the prevention of fungal contamination in their seeds. Sterilization by ionizing radiation provides food free of pathogenic or toxigenic microorganisms. Was performed to evaluate the inhibitory effect of gamma radiation with Co-60 for contamination by Aspergillus aflatoxigênico samples of sunflower seed, seed germination rate and mycobiota present with or without radiation. Samples were obtained at the street fair in Vitoria de Santo Antao, PE, Brazil. We analyzed samples of sunflower husk (big grain – A and small - C) and shelled (B). Then the samples were packaged and submitted to the pump radiation from cobalt-60 at doses of 0, 2.5, 5 and 10 kGy, and plated in triplicate in culture medium DRBC and AFPA, 30 seeds per sample. The plates were incubated at 25 ° C for 5 days. The evaluation of the mycobiota in the medium DRBC showed a predominance of Penicillium sp. in sample A, Aspergillus sp. (sample B), and Fusarium sp., Alternaria sp., Colletotrichum sp. and Cladosporium sp. in sample C. Rhizopus sp. was isolated from the seeds with or without shells (A and B) not irradiated. It was also observed the presence of toxigenic Aspergillus only in the middle AFPA sample of seed shelled (B) and radiation decreased by contamination in this sample, proportional to dose 33% (non irradiated) to 0% with 10 kGy. The germination rate of sunflower seeds also decreased in proportion to radiation dose, ranging from 73.3% of the samples (sample B shelled) to 0 with 10 kGy, to the samples A and B. However, in the sample C, even when there was still 10kGy seed germination in 36.6% of the samples, indicating that the gamma radiation has not prevented the use of seeds for sowing and also adapt themselves to the sanitary quality feed/human, as that decreased the fungal contamination.