Evaluation of fungal bio burden and mycotoxins presence in irradiated samples of medicinal plants purchased from wholesale and retail market

This present study evaluated the effect of gamma radiation on the fungal survival in packed medicinal plants, purchased from wholesale and retail market, in different period (0 and 30 days) after the treatment. Five kind of medicinal plants (Peumus boldus, Camellia sinensis, Maytenus ilicifolia, Paullinia cupana and Cassia angustifolia), were collected from different cities of Sao Paulo State, and submitted to irradiation treatment using a 60Co source (type Gammacell 220) with doses of 5,0 kGy and 10 kGy and at dose rate of 3.0 kGy/h. Non-irradiated samples (control group) were used for fungal counts and serial dilutions from 10-1 to 10-6 of the samples were seeded in duplicates and plated using the surface culture method in Dichloran 18% Glycerol Agar (DG 18) and were counted after five days at 25 deg C. The control group revealed the presence of genera Aspergillus and Penicillium, which are known as toxigenic fungi and a few samples of control group were within the safety limits of World Health Organization (WHO, 1998) to medicinal plants. In response to resistance of ionizing treatment, in the dose of 5 kGy, it was observed that the genera Aspergillus, Phoma and Syncephalastrum were radio-resistant after the process (day 0 and 30th day). The treatment by gamma radiation was effective in decontamination of all irradiated samples of medicinal plants, after 30 days, with the dose of 10 kGy and kept of veiled conditions. It was not detected aflatoxins in samples of control group, even though these samples were heavily contaminated with Aspergillus flavus. (author)