Use of chitosan film to control aflatoxins in peanuts

In this study, we evaluate the utilization on chitosan film to control the growth and aflatoxin production by A. parasiticus in peanut. The films were inoculated over the grains by aspersion or immersion methods. The chitosan coated grains were inoculated with 2.5 ml solution with 1.0x10(6) spores/ml and incubated at 25 degrees C for 7 days. The aflatoxin concentration was estimated by thin layer chromatography and densitometry. The fungus growth inhibition was observed by pathogen inoculation in Petri dishes with GYEP media plus 2% chitosan and incubated by 7 days at 25 degrees C. After incubation the colony diameter was measured and compared with the control. All assays were repeated five times. To verify morphological alterations, a spore/hypha suspension was incubated in media with chitosan and observed in scanning electron microscopy. Both methods (immersion and aspersion) were able to reduce the aflatoxin production significantly, 84.3% and 86.7%, respectively. The chitosan reduced the colonies diameters and promoted morphological alterations in A. parasiticus spores. With this, was observed that a 2% chitosan film, specially inoculated by aspersion, can to reduce A. parasiticus spores and aflatoxins concentrations in peanuts. This characteristic gives to this substance an excellent perspective to be used in aflatoxigenic fungi control.