The Nebraska Governor’s Conference on Ensuring Food Safety included a lively discussion on distillers grains and E. coli O157:H7. Dr. Jim Wells at USDA presented data that appears to show some correlation between certain levels of cattle-fed distillers grains and the levels of O157 that appeared in the hides of cattle. Recent research suggests that distillers grain does not increase the prevalence of O157 in cattle though it may increase the amount of the O157 in the cattle that already have the bug.
Some researchers are coming to believe that any issues surrounding distillers grains may be ameliorated by dietary supplements. Dr. Wells emphasized, however, that more research is needed. USDA believes that distillers grains are an important source of animal feed and appears committed to better understanding distillers grains and cattle nutrition.
2008 was a terrible year for makers of ethanol and biodiesel. Huge spikes in the prices of raw materials, natural gas and transportation and drops in the prices they received for their main products have driven many of them to cut back production, shutter plants or even seek bankruptcy protection. In additiion, U.S. biodiesel producers saw themselves faced with an antidumping investigation by the EU that might affect their export market.
If you thought it couldn’t get any worse, hang on.
The National Grain and Feed Association reports that at the International Feed Expo in Atlanta on January 27, Dr. Daniel McChesney of the Food and Drug Administration spoke about studies the agency has reviewed concerning distillers’ grains, the main by-product of ethanol, and glycerin, the main by-product of biodiesel. The information presented by the FDA’s Center for Veterinary Medicine is of concern to anyone in the biofuels industry, as well as anyone who feeds livestock or purchases, processes or consumes meat and poultry.
The FDA has tested 45 samples of distillers’ grains from ethanol plants and in over half of them detected antibiotics, including virginiamycin, erythromycin and tylosin. NGFA later learned that the concentration of those antibiotics exceeded the level (0.5 ppm) from a letter of no objection relating to virginiamycin issued in 1993 to the predecessor of Philbro Animal Health. There are no safe levels established for the other two antibiotics in feed grain. The FDA has 15 more samples to test and intends to make its final report available this summer.
With regard to biodiesel-derived glycerin, Dr. McChesney stated that the FDA does not consider it to be GRAS, or generally recognized as safe, for use as animal feed. Two issues raised concerns:
· Many samples contained more methanol than the 150 ppm level recognized as safe for animal feed; and
· Samples contained salt in concentrations as high as 16,500 ppm.
Accordingly, the FDA will be conducting a safety review of glycerin as a by-product of biodiesel. This will focus on the type of feedstock used, the manufacturing process and how the glycerin is introduced into feed.
Developing markets for by-products has been a significant challenge for the emerging biofuels industry. The latest news of the FDA’s concerns about both distillers’ grains and glycerin will increase those challenges in an already difficult environment.
We've previously discussed ongoing research concerning safety of distillers grains previously. An article on distillers grains and E. coli in Distillers Grains Monthly (Third Quarter 2008) suggests that the scientific debate continues, and questions remain unanswered.
Conflicting studies have now been released by Kansas State University and the University of Nebraska regarding the link between distillers grains and the presence of E. coli O157:H7. In December 2007, KSU released a study showing that E. coli O157:H7 levels were approximately two-fold higher in cattle fed dried distillers grains. In reaction to the KSU findings, researchers at Nebraska revisited their findings from an earlier distillers grains feeding trial and arrived at a conclusion different than that of KSU.
Nebraska researchers found E. coli O157:H7 produced at statistically significant levels between diets low in distillers grains and those high in distillers grains. However, neither of those diets produced E. coli O157:H7 at levels statistically significant from the control diet. The Nebraska data also showed that diets low in distillers grains may help animals to shed the microbe in feces.
Apart from the studies, the article explains that much remains unknown about the effects of distillers grains when introduced into cattle diets. For example, researchers do not know why cattle respond differently when fed dried distillers grains-spiked steam-flaked corn and dried distillers grains-supplemented dry-rolled corn. Researchers are also unaware of how distillers grains produced from different sources--sorghum, barley, and so forth--may affect cattle differently.
Hopefully, we will learn more in October 2008, when Nebraska plans to make available a study involving 480 cattle and high levels of distillers grains. Until then, it appears the link between distillers grains and the presence of E. coli O157:H7 in cattle remains unsettled.