The occurrence of culmorin and hydroxy-culmorins in cereals

Forty-five samples from 1988-1995 of naturally contaminated grain, barley, wheat and oats, three samples of mixed feed, and 16 samples of grain artifi cially inoculated with Fusarium culmorum during the flowering stage were an alysed for deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-acetyl-DON), cul morin and hydroxy-culmorins. These compounds are secondary metabolites prod uced by the fungal species F. culmorum and F. graminearum. Acetonitrile-wat er extract of the samples was purified on a Mycosep(TM)#225 column, derivet ized using pentafluoropropionic anhydride (PFPA) and analysed by gas chroma tography-mass spectrometry (GC-MS). The amount of each of culmorin, 5-, 12- , 14 and 15-hydroxy-culmorin and one unknown hydroxy-culmorin were determin ed relative to the amount of DON plus 3-acetyl DON for each sample. The rat io between the total amount of culmorin compounds and the DON compounds ran ged from 0.14 to 1.07 in the samples. This study shows that there is a stro ng correlation between the amount of DON present in the grain and the amoun t of culmorin and hydroxy-culmorins present. The ratio of each of the culmo rin compounds relative to the amount of DON compounds were in the same rang e in the grain artificially inoculated by F. culmorum as found in an earlie r study for F. culmorum strains cultivated on rice, while the hydroxy-culmo rin profile in the naturally contaminated grain was more similar to what wa s found for the F. graminearum cultures in the same study [1]. These result s indicate that F. graminearum may be a relatively important source for DON in grain also in relatively cold areas.