Resumo

The fungus Trichoderma is used to modify substrates improving the availability of nutrients and functional compounds in co-products and agro-industrial residues for use as food or feed. This type of substrate, by handling or constitute the outer portions of the grain may be contaminated with biological or chemical agents, especially mycotoxins. This study evaluated the ability of the fungus Trichoderma reesei (QM9414) to decrease the level of aflatoxin B1 (AFB1) on Potato Dextrose Agar (PDA) 4%, to establish the minimum initial spore and the time required for the degradation of this mycotoxin. The cultivation of the microorganism was previously performed on potato dextrose agar fortified and the residual levels were determined every 24 hours using high performance liquid chromatography connected to a fluorescence detector. The extraction method The extraction method Amaya Soares and Rodrigues (1989), was adopted by proving its efficiency in extracting aflatoxins, this method was adapted to minimize the amount of solvent.The numbers of spores were initial inoculum of 4 x 102 spores g-1, 4 x 104 spores g-1, 4 x 106 spores g-1 in the intervals of 0, 24, 48, 72, 96 and 120 hours. The method to evaluate residual levels of AFB1 presented limit of quantification of 1.2 ng g-1, 73% recovery and coefficient of variation of 2.3%. From the residual levels were estimated the decontamination noting that to achieve the maximum percentage (100%) took 96 hours for the cultivation experiments with 4 x 102 spores g-1 and , 4 x 106 spores g-1. Therefore the number of spores initial 4 x 102 spores g-1 can degrade AFB1, which , which is interesting for application without affecting the functional characteristics of a naturally contaminated matrix, showing that the micro-organism Trichoderma reesei is a promising agent for studies degradation of aflatoxins.