DES MOINES, Iowa — Because of no positive finds in testing of aflatoxin since last November, the Iowa Department of Agriculture and Land Stewardship (IDALS) has halted all aflatoxin screening and testing of milk received in Iowa, which became effective March 1.

“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,” said Iowa Agriculture Secretary Bill Northey.

The IDALS started testing for aflatoxin on Aug. 31, 2012, because of the severe drought conditions in Iowa last summer, which can produce aflatoxin in corn. The order required Iowa milk processors to screen all Grade A and Grade B farm bulk milk pickup tankers and farm can milk loads for aflatoxin on a weekly basis, continuing indefinitely.

A naturally occurring byproduct of a type of mold, aflatoxin can affect crops, such as corn, used in animal feed. During the six months in which the testing requirement has been in place, the IDALS has seen only four loads of milk test positive for aflatoxin and all four were destroyed.

The last load to test positive was on Nov. 7, with an estimated 88.46 million gallons of milk tested since that positive test.

Last fall, the IDALS also conducted a statewide corn sampling program to determine the prevalence of aflatoxin, receiving a waiver from the U.S. Food and Drug Administration (FDA) that permitted IDALS to allow corn containing more than 20 parts per billion (ppb) of aflatoxin to be blended with non-aflatoxin containing corn for animal feed for non-dairy animals. The FDA’s current blending waiver is in place until June 1, 2013.

According to IDALS, the FDA has established guidelines for acceptable aflatoxin levels in corn based on its intended use. Corn containing aflatoxin in concentrations of greater than 20 ppb cannot be used for human consumption or to feed dairy animals, or for immature livestock of other species.

Last September, the FDA approved IDALS’ request to allow corn containing more than 20 ppb of aflatoxin to be blended with regular corn for livestock feed. Corn containing aflatoxin at 100 ppb or less can be used in breeding cattle and swine, and mature poultry. Corn with 200 ppb or less can be used with finishing swine greater than 100 pounds in weight, and corn with 300 ppb or less can be used in finishing beef cattle.

The IDALS said the mixture of aflatoxin with corn of lower levels or no aflatoxin at all allowed the corn to be safely fed to livestock pursuant to the FDA’s longstanding guidelines, by which farmers had to sign a compliance agreement before blending. The FDA granted the state of Iowa similar requests for the blend when aflatoxin was found during the droughts of 2003 and 2005.

In late August 2012, there were several reports of aflatoxin detected in southern and central Iowa fields, with levels of aflatoxin ranging from 8 to almost 200 ppb.