Aflatoxin Dealing Double
Blow To Texas Corn Growers

HARLINGEN, Texas —(AP)— The drouth has dealt a two-fisted blow to corn growers in South Texas — not only do they have reduced yields because of the drouth, but most of what's left is contaminated with toxin-making fungi exacerbated by dry weather.

The hot, dry weather has caused corn kernels to crack open, clearing a path for aspergillus flavus and aspergillus parasiticus to grow. The fungi produce aflatoxin, a cancer-causing chemical that can cause liver damage in humans and animals.

According to federal restrictions, corn with aflatoxin levels at or above 20 parts per billion can't be sold for human consumption or as dairy cattle feed. The maximum level for livestock feed is 300 parts per billion. Corn with levels over 1000 parts per billion must be destroyed.

"Aflatoxin is a chronic problem in South Texas," said Tom Isakeit, a plant pathologist with the Texas A&M Agricultural Research and Extension Service. "We really don't have any good news for control of it."

Mark Waller, an Extension economist, said the indication from South Texas grain elevators this year is that at least 60 percent of the corn coming in is infected with aflatoxin, which can also be found on peanuts, cottonseed and sorghum.

Most growers didn't know their corn was infected until they tried to sell it and it was chemically tested.

"You can't see that you have a problem," Isakeit said. "The corn looks fine, but then you analyze it and it's filled with aflatoxin."

The amount of aflatoxin in the corn determines how much money growers can make. Corn that's safe for human consumption sells for more than lesser grades used for livestock feed.

Growers are currently getting anywhere from $2 to $2.50 per bushel for their corn, Waller said. If the corn is infected, they have to sell it at a discount. Although growers can put the corn through a detoxification process, that also costs money.

"If you only had half a crop to begin with, all of a sudden you're in a whole lot worse shape," Waller said.

On top of that, other southern states, like Arkansas, Mississippi and Louisiana, are contending with aflatoxin-contaminated crops and are trying to sell the lower grade corn to the same feedlots as Texas growers. The increased competition means lower prices, even lower than during the 1996 drouth.

"Two years later, we're looking at very large supplies," Waller said. "It's very easy to get corn. The discounts that we're taking on this new crop of corn are much higher this time."

Although aflatoxin can cause liver cancer in humans, there are few documented cases in the United States since grains meant for human consumption are first tested, Isakeit said.

In less developed countries with higher aflatoxin levels in food, there are higher rates of liver cancer, he noted.

Aflatoxin also causes liver damage in animals and can be passed into the milk of dairy cows. Cattle raised for food, however, can be fed higher amounts of aflatoxin-contaminated grain because they are not going to live very long, Isakeit said. The carcinogen is not passed on to humans who eat the meat because it doesn't accumulate in the muscle.

Isakeit said researchers are trying to develop an aflatoxin-resistant strain of corn. So far, however, they've been unsuccessful.