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MOLDS AND MYCOTOXINS What else could be in your
distillers grains
Tamra JacksonExtension Plant Pathologist
University of Nebraska-Lincoln
Co-PIs: G. Yuen, M. Carlson, L. Bullerman, L. Du
Ear Rots• Fusarium ear rot
• Random white patches• Gibberella ear rot
• Usually a red tip rot• Mycotoxins
• Fumonisin• Vomitoxin• Zearalenone• Tricothecenes
• Conditions• Wetness and high humidity
Ear Rots• Aspergillus ear rot
• Green-yellow patches• Rare
• Mycotoxins• Aflatoxin
• Conditions• Heat and drought
followed by wetness and high humidity
Mycotoxins• Concentration in grain is determined by
– Fungal infection– Growing conditions and plant stresses
• Drought and wetness during growing season• Storage conditions (dry to <15% w/n 48 hrs)• Kernel damage
– Heat stable• Distillers Grains
– Concentration increased 3X by volume• Removal of starch (2/3) during distillation
Mycotoxin Effects
Toxin Produced Toxic Effects
Species Affected
aflatoxin acute toxicity (liver) liver cancer immune suppression
many human humans, animals
fumonisin blind staggers pulmonary edema esophageal cancer
horse swine human
Acutely toxic (immediate)
Chronic (carcinogenic)
Objective
To measure the concentrations of 4 important mycotoxins (i.e. aflatoxin, fumonisin, vomitoxin, and zearalenone) in distillers grains samples obtained from Nebraska ethanol plants
Materials and Methods• 72 Samples
– 6 of 8 NE Crop Reporting Districts• Collected January to April 2007• 64 were wet and 8 dry
– 7.5 to 73.1% Moisture• Mycotoxins measured
– Aflatoxins, Fumonisins, Zearalenone, Vomitoxin (DON)
– HPLC by Trilogy Labs
Materials and MethodsNebraska Ethanol Plants
Materials and MethodsNebraska Crop Reporting Districts
Materials and MethodsSamples Collected from NE Crop Reporting Districts
0
5
10
15
20
25
30
C E NE N S SW
ResultsGOOD NEWS
• Aflatoxin detected in 26% of samples & all below 20 ppb (dairy cattle)
• Fumonisin below 50 ppm (cattle)
• Zearalenone not detected in any samples
BAD NEWS• Fumonisin detected in
100% of samples• When adjusted for
moisture, 65% > equine concentrations and 24% > swine
ResultsLIMITATIONS & CONSIDERATIONS• Single year (2006 corn)• NO samples from SE district• No storage data• No data on initial
concentrations• High variability
REGIONALLY• Highest aflatoxin
concentrations from NE district
• Highest fumonisin concentrations from the E district
More Questions and Projects• Post-harvest and –distillation
infection and mycotoxin contamination?
• Impacts of storage and handling on distillers grains?
• Other microorganisms?• Currently
– Seeking more distillers grains samples for a second study
Acknowledgments
Funding provided by UNL Layman Award
Samples collected by Nebraska Dept. of Agriculture