Iowa has dropped a requirement that all milk received in the state be tested for aflatoxin, the toxic byproduct of a mold that attacks corn during a drought, the state's agriculture department said Friday.
Aflatoxin was more prevalent than usual in the 2012 corn harvest, which was hit by the biggest drought in the grain belt in 50 years. The worst outbreak appeared to have occurred just south of Iowa, the top corn producer.
Mandatory milk testing in Iowa began on August 31 amid fears that cows eating corn infected with the naturally occurring toxin would pass the substance through to their milk.
Over the next six months, the Iowa Department of Agriculture said, only four loads of milk tested positive for aflatoxin. All four were destroyed.
The last load of milk to test positive was on November 7. Since then, approximately 88.46 million gallons of milk have been tested, the department said. The testing requirement was dropped as of Friday.
"We appreciate the cooperation from milk processors and farmers throughout this process as we work with them to ensure the milk supply stays safe and free of aflatoxin," Iowa Secretary of Agriculture Bill Northey said in a statement.
According to crop insurance data from the Department of Agriculture, payouts in 2012 for mycotoxins, of which aflatoxin is the most common, totaled nearly $75 million, triple the level of a year ago.
Nearly 85 percent of the claims were filed in six states: Arkansas, Illinois, Indiana, Kansas, Mississippi and Missouri.
Human exposure to high amounts of aflatoxin is rare. But aflatoxin contamination prompted the Hy-Vee Inc grocery chain last week to recall different product lines of its privately branded dog food due to elevated levels of aflatoxin contained in the corn used to make the pet food.
The dog food, all manufactured at a plant in Kansas City, Kansas, was recalled across eight Midwestern states.
Aflatoxin also caused a series of pet food and livestock food recalls in December 2011.
Mycotoxins are produced by fungi and can cause kidney and liver damage, suppress the immune system and disrupt absorption of nutrients, among other problems.
(Reporting by Julie Ingwersen; Editing by Grant McCool)