mycotoxin levels, and Fusarium has been used as a source ... Ottawa, Ontario, KlA 0C6 Canada. strate for the ..... ed in the 2,000- and 2,800-ml flasks, in spite of.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Sept. 1983, p. 625-629
Vol. 46, No. 3
0099-2240/83/090625-05$02.00/0 Copyright 0 1983, American Society for Microbiology
Deoxynivalenol, Acetyl Deoxynivalenol, and Zearalenone Formation by Canadian Isolates of Fusarium graminearum on Solid Substratest R. GREENHALGH,* G. A. NEISH,t AND J. D. MILLER Chemistry and Biology Research Institute, Agriculture Canada, Ottawa, Ontario KIA 0C6 Canada
Received 28 February 1983/Accepted 20 June 1983
Three isolates of Fusarium graminearum (DAOM 180377, 180378, and 180379) screened for their ability to produce mycotoxins on the solid substrates corn and rice. They all produced deoxynivalenol and zearalenone on corn. On rice, only DAOM 180378 and 180379 produced significant amounts of these mycotoxins, with levels of deoxynivalenol being much higher than those of zearalenone. The effects of the initial moisture content before autoclaving, incubation temperature, and time were studied with isolate DAOM 180378. At 19.5°C the main product was zearalenone, whereas at 25°C both deoxynivalenol and zearalenone were formed. Higher incubation temperatures (28°C) favored deoxynivalenol formation, the maximum amount being 515 ppm (515 ,ug/g) formed after 24 days at an initial moisture content of 40%. The maximum level of zearalenone produced at the same temperature was 399 ppm, but at an initial moisture content of 35%. Other factors, such as pH, oxygen and carbon dioxide concentrations, and size of the culture flask also appeared to affect the production of mycotoxins. were
Interest in the trichothecene mycotoxins has increased in recent years as a result of widespread occurrence of deoxynivalenol (vomitoxin; 3,7,15-trihydroxy-12,13-epoxytrichothec9-en-8-one) in corn (7) and cereal grains (9, 11). Deoxynivalenol is a fungal secondary metabolite produced by several Fusarium species (13). Its occurrence as a natural contaminant in grains, however, is usually associated with Fusarium graminearum Schwabe infections in temperate climates (10). It was first detected in barley in Japan and was characterized by Morooka et al. (5). It has been identified as a toxic principal responsible for decreased weight gains, feed refusal, and emesis in swine (3, 8). The need for feeding and toxicological studies with deoxynivalenol has created a demand for large quantities. Levels in naturally infected grains (
