When multiple farms had to dump milk over the last week due to aflatoxin contamination, the impact of this year’s drought reached a new level. Speculation about the potential aflatoxin contamination in this year’s crop has been ongoing and was rightfully stimulated by the high temperatures and drought conditions experienced throughout the Midwest. Now, with 26 percent of the U.S. corn crop harvested as of Sunday, the magnitude of aflatoxin contamination is just beginning to be quantified.

They key number to remember when quantifying aflatoxin contamination is 20 ppb. This is both the FDA Action Level for feeds whose intended use is unknown, and the low end of the range in which a total mixed ration will cause milk contamination to be greater than the FDA allowable level. The chart below shows the feed products and states from which Dairyland Laboratories has found samples to contain greater than 20 ppb aflatoxin.

At this early stage in the harvest season, it’s not surprising to see that the majority of feeds with significant contamination were corn and corn silage from states that experienced severe drought. It’s not unreasonable to expect that contamination will eventually filter into corn byproducts and other states as commodities are bought and sold.

As with most years, the majority of samples that are tested for aflatoxin contain only very low levels.  However, as we move forward with this crop year, being aware of potential aflatoxin sources and monitoring contamination levels will become increasingly important. Particular caution should be applied to corn and corn silage stored in bags or vertical silos, since these feeds can make up a large portion of the diet and these storage structures will have as much variation in contamination as the fields from which they were harvested from.  

More information about aflatoxin, including proper sampling instructions, interpretation of results, special pricing, and up-to-date mold and toxin summaries are available at dairylandlabs.com.

Samples confirmed to have Aflatoxin >20 ppb
Dairyland Laboratories Inc. | July-September 2012

Corn Silage x   x x x       x  
Corn Grain x x x   x x x x    
Distillers x                  
Grain Mix x   x              
Malt Sprouts   x                
Corn Gluten Feed                   x