Ethanol’s main by-product, which is sold as livestock feed, has raised
potential food
safety concerns.

Several studies have linked the byproduct, known as distillers grain, to
elevated rates of E. coli in cattle. And now, distillers grain is facing
further scrutiny because the

Food and Drug Administration has found that it often contains
antibiotics left over from making ethanol.

Ethanol production relies on enzymes, yeast and sugar to convert corn
into fuel. And just as the wrong bacteria in the body can sicken people,
it can also cause a variety of ailments in a batch of ethanol.

Mark von Keitz with the University of Minnesota’s Biotechnology Institute
said in ethanol production, the main enemy is a bacterial bug that makes
lactic acid.

“What these organisms do is they also compete with the yeast for the
sugar,” said von Keitz. “But instead of making alcohol, they
make primarily lactic acid.”

If enough of the bacteria are present, von Keitz said fermentation can be
ruined.

“It gets acidified to the point that the yeast is no longer able to
properly produce ethanol, and then you’re stuck with a big batch of corn
mash,” said von Keitz.

If that happens, there’s no ethanol and no profit. To prevent the
problem, producers rely on medicine.

“What people operating these plants are trying to do is to keep
these lactic acid bacteria in check,” said von Keitz. “And one
way of doing that is with the help of antibiotics.”

Ethanol producers use penicillin and a popular antibiotic called
virginiamycin to kill bacteria. And that raises two potential
concerns.

One is that these treatments might promote the growth of bacteria that
are resistant to antibiotics. The development of these
“superbugs” is a major concern in
health care because
they reduce the effectiveness of medicines.

Von Keitz found some bacteria that were, in fact, resistant when he
sampled bacteria at four Midwest ethanol plants several years
ago.

The second concern is that the antibiotics could find their way to humans
through the food chain.

The

U.S. Food and Drug Administration has taken a mostly hands-off
approach to the use of antibiotics in the ethanol industry. But amid
increasing concerns over food safety in recent years, the agency is
taking a closer look.

“A year ago we put a survey out to the FDA field people to collect
samples of those distillers grains, and start analyzing for antibiotic
residues,” said Linda Benjamin, a chemist with the FDA’s Center of
Veterinary Medicine.

Samples were requested from 60 ethanol plants, including some in
Minnesota. She said testing showed that many contained antibiotics,
mainly four types.

“Penicillin, virginiamycin, erythromycin and tylosin,” said
Benjamin.

At this point the story gets murky. Benjamin won’t say if any of the
antibiotics exceeded federal guidelines.

Those guidelines are part of the problem; they’re a patchwork and far
from definitive on what levels of antibiotics in distillers grain are
safe.

If the FDA decides to restrict antibiotics in the ethanol industry, it
could have far-reaching consequences.

Distillers grain is a major source of low-cost livestock feed. Any
restrictions on its sale and use as feed will hurt the profit-scarce
ethanol industry and the livestock farmers who rely on it.

Charlie Staff, executive director of the Distillers Grain Technology
Council, said distillers grain is one of the few dependable moneymakers
left for the ethanol industry.

“If they didn’t have distillers grain as a revenue, many more of
them wouldn’t be able to operate,” said Staff.

Meanwhile the regulatory process continues to play out. The FDA will test
more distillers grain samples, and expects to issue a final report this
summer.

The maker of virginiamycin declined to comment, but the company is
expected to ask the FDA to approve the antibiotic as a human food
additive.

Depending on how this regulatory battle winds up, it could change the way
Minnesota’s 18 ethanol plants distill their product.

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