Scientists Study Possible Link Between Ethanol Byproduct and E. coli

January 29th, 2008

The Des Moines Register
By Philip Brasher
Register Washington Bureau

Washington, D.C. – A nationwide surge in beef recalls has pointed the finger at an unlikely culprit – the nation’s fuel ethanol industry.

Studies at two universities suggest that feeding cattle a byproduct of ethanol production known as distillers grains may increase levels of a deadly form of E. coli bacteria.

Concerned about those findings, U.S. Department of Agriculture scientists have recently put 300 cattle on a diet of distillers grains and are testing them regularly for the bacteria. Results won’t be known until later this year.

Cattle producers and the ethanol industry both have a lot at stake in the research. The increased use of corn for ethanol has driven up the cost of grain for livestock feed. But the availability of cheaper distillers grains has offset the impact of those higher corn prices on livestock producers while providing a valuable revenue stream to ethanol plants.

“To those of us here in the Midwest, being able to utilize distillers grains gives us a huge advantage over the rest of the country,” said Kevin Carstensen, who operates a cattle feeding operation near Odebolt in northwest Iowa and also is an investor in a local ethanol plant.

Production of distillers grains has soared along with the growth of ethanol. About a third of the corn that goes to an ethanol plant is turned into distillers grains.

Meatpackers recalled a record 33.4 million pounds of beef last year for possible E. coli contamination, up from just 181,900 pounds in 2006, according to the USDA. The old record of 25.6 million pounds was set in 1997.

The 21 recalls last year – the most since 2002 – included one by now-defunct Topps Meat Co. that totaled 21.7 million pounds.

The USDA’s undersecretary for food safety, Richard Raymond, said he thinks distillers grains are one of several factors behind the spike in recalls.

“There is just something different” going on, he said in an interview last week in Arlington, Va., where he was attending a special industry conference on the E. coli problem.

Healthy cattle carry E. coli bacteria in their intestines. It isn’t harmful to them but it can be deadly to people, especially children and the elderly, who eat undercooked ground beef. The bacteria get into the meat when it is processed. Proper cooking destroys the germ.

The government has not released information on the number of E. coli-related illnesses in 2007.

Raymond said the government had no intention of restricting the use of distillers grains even if the E. coli link is confirmed, and would instead leave it to the industry to decide how to address the issue. One possibility, he said, is to vaccinate cattle.

“I’m not about to tell the cattlemen what they are going to feed their cows,” he said.

No E. coli vaccine has yet been approved or use in cattle.

There are other theories for the surge in recalls. One is that the bacteria spread from steer to steer more easily last year because feedlots were muddier than usual. Another possibility is that bacteria have evolved in a way that makes them harder to detect. Yet another theory is that immigration raids have robbed slaughterhouses of experienced workers.

“There are a lot of theories floating around right now and people aren’t sure what the answer is,” said Chris Waldrop, who follows food safety issues for the Consumer Federation of America.

“One of the things that concerns us is whether this is an actual spike we’re seeing or whether the past years were unusual. Maybe we thought we had it under control and we really didn’t,” he said.

Scientists stress that more research needs to be done on the possible link to distillers grains. They say they aren’t sure why distillers grains would lead to higher levels of E. coli. One possibility is that it changes the acidity of a steer’s gut in a way that encourages bacterial growth.

Researchers at Kansas State University noticed the possible E. coli connection to distillers grains in 2005. A second study found a twofold increase in E. coli levels in cattle fed the product compared with those that ate only corn. Research at the University of Nebraska showed mixed results. Cattle fed a diet comprising 10 percent to 30 percent distillers grains actually had lower rates of E. coli than cattle on a diet of all corn. But cattle fed 40 percent to 50 percent distillers grains showed higher E. coli rates.

“That would suggest that there was something about these distillers grains diets that influenced the ability of these cattle to shed E. coli,” said David Smith, one of the scientists who worked on the Nebraska research.

Producers in Iowa typically feed their cattle 30 percent to 40 percent distillers grains, according to the Iowa Cattlemen’s Association.

The cattle in the USDA study, which is being conducted at the department’s Meat Animal Research Center in Clay Center, Neb., are getting a diet of 40 percent distillers grains. The cattle are being tested monthly until they reach their full weight this spring. Their E. coli levels will be compared with cattle on an all-corn diet.

“If there is any effect on the pathogens, we’ll see it,” said Mohammad Koohmaraie, who runs the research center.

A series of outbreaks during the 1990s and again in 2002, when a Colorado slaughterhouse recalled 18.6 million pounds of beef, forced meatpackers to install a variety of sanitation steps, including steam treatment, to prevent contamination of beef. After the 2002 outbreaks, the USDA ordered processors to take additional measures and recalls immediately plummeted.

The USDA announced additional steps last fall as the surge in recalls was mounting. Plants were audited to see what they were doing to prevent E. coli contamination. The results of the audit have not yet been released. Federal inspectors are also doing special testing in processing plants and have started sampling imported beef as well.

Raymond said the USDA needs to find out whether cattle have been carrying more of the bacteria than they used to and if there are new strains developing.

“We’ve got to get upriver instead of just testing product as it goes out the door,” he said at the industry conference.

Cattle producers will be watching closely to see what the government finds.

Carstensen, who is president of the Iowa Cattlemen’s Association, said he pays $35 a ton for distillers grains, the equivalent of $2.85 a bushel for corn. In his area, corn has been selling for more than $4 a bushel. It takes the equivalent of 70 bushels of corn to fatten a steer.

More research is needed on the possible link, he said, but processing plants have the necessary controls to prevent contamination.

“We don’t live in a perfect world,” he said. “To try to say that the silver bullet that’s going to take care of all food-borne pathogens is here, that’s a stretch.”

Reporter Philip Brasher can be reached at (202) 906-8138 or pbrasher@dmreg.com

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