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