antibiotic-resistance1In late April, Tyson Inc. joined the ranks of food companies and restaurant chains declaring their intentions to go antibiotic free. The list includes big poultry producers like Perdue Farms and Pilgrim’s Pride Corp. and restaurant chains such as McDonalds, Chick-fil-A and Chipotle Mexican Grill. The move to minimize or eliminate nontherapeutic use of antibiotics in meat production is a response to the increasing concerns about drug resistant bacteria affecting people. Drug resistance in tuberculosis cases and antibiotic-resistant staph bacteria (MRSA) are two that receive a lot of attention these days.

It is far from a new issue, however. The U.S. Food and Drug Administration first proposed restricting the use of antibiotics in feed in the mid-1980s, when producers were increasingly using them as growth enhancers and preventative aids in confinement feed operations. Industry successfully stayed the FDA’s hand in the U.S., even while European countries moved to ban nontherapeutic antibiotic use in animals, the first being Sweden in 1986. In the past two years, FDA has developed a voluntary approach to “achieve the common goal of more judicious use of medically important antimicrobials in animal agriculture.” The feed industry is getting on board, agreeing to move toward reserving certain antibiotics for use under a veterinarian’s supervision to treat animal illnesses.

The impact on the ethanol industry could be significant. The industry has long used low doses of antibiotics in propagation and fermentation tanks to keep yield-reducing bacteria counts at low levels. A full-blown bacterial infection is a serious issue that can halt production. The miles of pipes, hundreds of valves and dozens of tanks in an ethanol plant provide multiple places for bacteria to hide and proliferate. As a result, sanitation procedures have become much more sophisticated, with clean in place (CIP) systems now commonly used and close monitoring of infection indicators standard operating procedure. Nonetheless, some estimates say 70 percent or more of U.S. ethanol producers still routinely rely upon antibiotics.

The likelihood of problematic antibiotic residues getting into the final distillers grains product is low, according to research conducted at the University of Minnesota. A team led by Jerry Shurson, professor of swine nutrition and a known expert on distillers grains, studied the question in 2011, publishing a paper, “Presence and biological activity of antibiotics used in fuel ethanol and corn coproduct production,” in the Journal of Animal Science. Over a year’s time, the team gathered 159 samples of wet and dry distillers grains from livestock feeders getting product from multiple ethanol plants. “Not all samples had antibiotic residues, and those that did were very low—many magnitudes lower that what FDA allows,” Shurson recalls. The research went one step further, examining the premise that the high temperatures and pH conditions in the ethanol process after fermentation deactivate any residual antibiotics. To test that, the samples were exposed to two sentinel bacteria, a strain of E coli and one of listeria. Bacteria grew on all cultures but one—and that was a sample where no antibiotic residues had been detected.  Based on that research, Shurson’s assessment is that the risk of residual antibiotics in distillers grains is low, given the relatively low incidences of low concentrations found in the samples that are not very biologically active. There is a further dilution affect, he adds, when the distillers grains are incorporated into rations at rates of between 5 and 30 percent.

Despite those findings, the antibiotic question is not likely to go away, Shurson adds. And, it has a global reach. Last November in Bangkok, at a distillers grains seminar hosted by the U.S. Grains Council, the question of antibiotic residues in distillers was raised. Many poultry producers in Thailand export to the European Union, which has strict standards on antibiotic residues. Not one to give a pat response when asked about a scientific question, Shurson found the presentation on his laptop and walked the Thai audience through the university study, explaining not only the findings but issues surrounding the methodology. It is challenging to measure minute amounts of antibiotics, he explains. There are questions surrounding the best analytical methods and a lack of standardization that makes comparisons difficult. “Many people think that because I sent my sample to the laboratory, the results are the gospel truth,” he adds, explaining there can be issues with false negatives and positives.

While the science is indicating the risk for antibiotics in distillers grains is low, Shurson told his listeners in Bangkok that the science is backed by experience. There are two sensitive markets in the U.S—dairy and laying hens—where the milk and egg products are closely monitored and tolerances for antibiotic residues are quite strict. “If there were a problem with residues, they wouldn’t use distillers,” Shurson says, “and that’s not the case.”

Dennis Bayrock, research director for PhibroChem Ethanol Performance Group, reinforces the case that little antibiotic residue is found in distillers grains. More than 300 samples were tested by Phibro without any detection of virginiamycin residues above limits, Bayrock says, and other studies have reaffirmed levels of virginiamycin in samples below the detection limit. Virginiamycin is the most widely used, although not the only, antibiotic in the ethanol industry.

A focus on minute antibiotic residues could be misplaced, Bayrock suggests. For one, while antibiotics and other chemicals can be detected in extremely low amounts, he says, a zero tolerance approach is not practical. “A subtler point that most people don’t realize is that the clinical bacteria that do or do not show resistance in human medicine are just not isolated to any significant levels in an industrial ethanol plant,” he says. While some studies have isolated E coli in stored grain and soil at facilities the bacteria are likely destroyed as processing begins, as they are not found in plant microbiological audits, he adds. Furthermore, there is no virginiamycin-related human drug approved for any serious and unique human disease.

The industry’s approach has matured, he says. The team with Phibro Ethanol Performance Group helps ethanol producers fine tune the process to minimize upsets. “Putting good practices and CIP practices and auditing at a plant comes first,” he explains. Procedures are audited and yeast health and microbiology are monitored. “The philosophy I train our field staff in is to look at process first, help the plant, and then use our products with what contamination is remaining. In the old school way of thinking, they’d say: ‘if 2 parts per million [of antibiotics] worked, let’s throw some more in; if it worked over here it should work over there.’ We have moved away from this trial-and-error thinking. We make sure everything is working correctly, and then use our products when necessary.”

Bayrock is adamant that antibiotics are necessary. “You need to have both an effective CIP cleaning program in place to take care of the bulk of the contaminants present and organics. You also need to have an effective antibiotic regimen. There are areas of the plant you can’t CIP. For example, in the fermenter when you are actually fermenting. You can’t put caustic or harsh chemicals in there.

Likewise, there are areas where antibiotics are ineffective. You can’t use antibiotics for CIP. A proper and optimal combination of both CIP and antibiotics is the best approach for maximizing the performance of the plant.”

Ready Alternatives
Tyson’s announcement that it was moving away from antibiotic use in chicken rations, though, has had a quick impact on the ethanol industry. Three weeks after the announcement, BetaTec Hop Products personnel had received several calls from ethanol producers wanting to learn more about the BetaTec program, says John Forte, vice president. “We’ve worked with a couple just recently who have said, ‘I’ve signed a commitment that I won’t use antibiotics. I need to make a change.’”

BetaTec’s products are derived from hops plants, a natural solution for antimicrobial action, yeast nutrition and flavoring that predates the antibiotic era by centuries. Forte’s company, for instance, goes back 250 years in Europe. Going green and using a nonchemical approach is a conscientious decision that isn’t made overnight, and can’t be switched on and off, Forte says. “First a plant has to rationalize it, because a green program, let’s face it, costs more money. And that expense, rightfully so, has to be justified at the shareholder level. When somebody like a Tyson says we’ll only buy certified product, then there’s a price justification and reason beyond it’s the right thing to do.”
Antibiotic-free distillers grains has been offered within the ethanol industry for a few years, but it hadn’t caught on partly because there was no offsetting premium.  Forte says that’s changing, “There’s definitely a premium that’s starting to be captured.”

“There’s a cost to the plant to switch from antibiotics to us or a different program,” he continues. BetaTec approaches it as a value-added proposition and a partnership with a plant. “You can work with a plant to clean it up, get it off antibiotics and nurture the yeast in a green way where you do get higher yields to justify the price.”

Other companies are introducing new chemical-based antimicrobials. Two, Solenis LLC and Anitox Corp., rolled out new product offerings at the International Fuel Ethanol Workshop in Minneapolis that they’ve been testing at cooperating ethanol plants for the past couple of years.

Known in the ethanol industry for its water treatment and oil extraction aids, Solenis (formerly Ashland Water Technologies) is introducing a new line of fermentation aids designed to be yeast friendly while degrading or killing competing bacteria. The goal has been to provide options that work in conventional fermentations as well as in the elevated pH required for cellulosic and isobutanol processes, explains Allen Ziegler, global biorefining marketing director. One of the three formulations is for use in yeast propagation and fermentation processes currently using minimal or no antibiotics. The second formulation has stronger antimicrobial action and the third combines the chemistry in the first two with chlorine dioxide to address upstream scaling issues, if needed. Ziegler, who also leads antimicrobial technology development, explains Solenis begins its development process for new chemistries by being sure the product will qualify as generally recognized as safe (GRAS). “We look long term,” he adds. “We want to be sure we won’t have regulatory issues in the future but still meet the requirements of the industry.”

Anitox Corp. introduced itself, as well as its new antimicrobial OptimOH, to the ethanol industry at FEW. The Georgia-headquartered company has offered pathogen-control and processing aids for the poultry, livestock, pet food and grain milling industries for almost 40 years. For the past couple of years, it has worked globally with several ethanol producers as well as the National Corn-to-Ethanol Research Center to bring its chemically based antimicrobial to the ethanol process. The company describes OptimOH as a thermostable, antibiotic-free, broad-spectrum, broad pH processing aid for ethanol production that leaves no residues in the distillers grains. “What we’re seeing in the field is that clients can remove antibiotics and maintain a consistent yield improvement,” says Eric Summers, who recently joined Anitox as technical business development manager biofuels.

Even if their customers aren’t supplying companies like Tyson or Chipotle, ethanol producers will be looking closely at the products and programs of companies featured here, along with others offering process aids such as DuPont, Lallemand and Ferm Solutions. Regulatory changes coming in the Food Safety Modernization Act are expected to require all plants to better understand potential hazards and upgrade their procedures in handling all inputs—chemicals, antibiotics and even incoming corn.


By Susanne Retka Schill Ethanol Producer Magazine