SURVEY OF AFLATOXINS AND OCHRATOXIN-A IN STORED TUBERS OF CYPERUS-ESCULENTUS L

The mold incidence, moisture contents, pH and levels of mycotoxins (aflatoxins B-1, G(1) and ochratoxin A) on/of/in rootstock snack (tubers of Cyperus esculentus L.) samples were monitored during a 150-day storage period. Whereas the mold incidence, moisture and mycotoxin levels increased with storage time, the pH declined during the same period. Altogether, 12 fungal species, mostly toxigenic, including Aspergillus flavus, A. parasiticus and A. ochraceus were isolated. At collection period only 3 of the 9 snack samples analysed contained trace amounts of aflatoxins. By 120th day, all the 9 samples were contaminated and the average levels were 454 and 80ppb for aflatoxin B-1 and aflatoxin G(1) respectively on the 150th day. Ochratoxin A was not detected before 120th day and then only at low levels, occuring in a maximum of four-samples and ranging between 10 and 80 ppb.