The Presence of Mycotoxins after Ninety Days of Storage in Fresh Chestnuts

A preliminary study in 2006 demonstrated that chestnut kernels from the Japanese × European cultivar 'Colossal' stored fresh (4°C) for more than 120 days could accumulate mycotoxins. In 2007, chestnuts from two traditional cultivars, 'Colossal' (Castanea sativa × C. crenata), and 'Eaton' (C. mollissima x C. crenata), and a Chinese selection (C. mollissima) called 'Ever-Fresh' were harvested and stored at 4°C in a produce cooler. After zero, 30, 60, 90 and 120 days of storage, the chestnuts were assayed for the presence of three mycotoxins, deoxynivalenol, ochratoxin and zearalenone, by competitive direct ELISA (Acumedia; Neogen Corp., Lansing, MI, USA) Five, healthy 350 g kernel samples of each cultivar were processed to extract the mycotoxins as specified by the manufacturer. Average concentration for each mycotoxin was recorded for each sample. For 'Colossal', 0.36 ppm, 64.92 ppb and 427.00 ppb, were found for deoxynivalenol, ochratoxin and zearalenone, respectively. For 'Eaton' 0.32 ppm, 13.02 ppb, and 388.34 ppb were found for deoxynivalenol, ochratoxin and zearalenone, respectively. For 'Ever-Fresh', 0.10 ppm, 4.28 ppb and 245.02 ppb were found for deoxynivalenol, ochratoxin and zearalenone, respectively. Mycotoxins were found in fresh chestnuts and increased each month after storage. However, each chestnut cultivar and selection had differing concentrations of mycotoxins and 'Colossal' showed the largest increase after 120 days. Before 90 days, mycotoxins concentrations never exceeded federal maximum tolerance or recommendation levels; however after 90 days 'Colossal' exceeded federal tolerance levels for deoxynivalenol and zearalenone. The Michigan selection known as 'Ever-Fresh' accumulated significantly (p<0.05) lower concentrations of mycotoxins when compared to mycotoxins present in 'Eaton' and 'Colossal'.