Focus on Biofuels: Quality control contributes to boost U.S. DDGS exports

The popularity of using U.S. dried distiller’s grain with solubles (DDGS) as a feed ingredient in dairy, beef, swine and poultry feeds has been increasing across markets worldwide. From Morocco to Indonesia to Saudi Arabia, many feed users are noticing the benefits of this economical, yet nutritional ingredient, a co-product of the ethanol- and alcohol-making process.

China is leading the way in imports, and received its second-ever bulk shipment of U.S. DDGS in early December 2009. According to the U.S. Grains Council, China imported 8,000 tons of U.S. DDGS in 2008. By the end of calendar year 2009, DDGS imports into China reached around 500,000 tons, reflecting more than a 6,000% increase.

There are many reasons why Chinese dairy, livestock and poultry producers find the product appealing, ranging from its color and appearance to its affordability and nutritional value.

Many DDGS purchasers buy based on moisture content and nutritional makeup, including starch, fat, fiber and protein levels. Spec sheets are often required to ensure the customer receives what they expect. Proper testing and instrumentation methods help ensure that ethanol producers deliver the quality and value their customers demand.

Testing for other parameters, such as the presence of toxins, is another main priority for ethanol producers. There is a variety of methods and instruments available to ethanol producers to reveal the makeup of their DDGS.

Nutrition testing
Most DDGS contracts specify the desired level of protein, fat, fiber and moisture, components that are collectively referred to as a nutritional profile.

Some importers do their own testing upon arrival of shipment to make sure they receive what’s stated in the contract; however, the shipper generally tests product before it ever leaves the plant to ensure it will meet those specs.

Perten Instruments, a supplier of analytical equipment, offers an instrument called the DA 7200 that can simultaneously analyze multiple nutritional components, including protein, fat, fiber, moisture, starch, sugars, ethanol, sulfur and others, using a near-infrared (NIR) spectrometer.

“The instrument tests for a complete nutritional profile,” says Wes Shadow, business development manager, Perten Instruments. “The purchaser needs more than one piece of information because the protein or fiber level alone won’t give them enough information to properly use it in their formulations.”

The DA 7200 can provide fast results by reducing the need for sample grinding or filtration of slurries, so the levels can be measured in about six seconds.

Moisture level plays an integral role in the value and profitability of DDGS.

“Though a simple measurement, moisture levels are critical,” says Shadow. “The plant must balance the energy costs of removing moisture with quality. High moisture levels can promote microbial growth and affect flowability. Overdrying or drying at too high a temperature costs the plant money and can damage the protein. Timely and constant monitoring is critical.”

The nutritional makeup is only one aspect of testing that’s done at an ethanol facility. As with any grain processing plant, the risk of toxins is ever-present and something facilities monitor closely.

Toxin testing
The presence of high toxin levels in U.S. DDGS is currently not an issue for Chinese importers, so there isn’t much U.S. DDGS testing conducted after it arrives in China.

“At the moment, China’s customs officials do not test imported DDGS for aflatoxin or other mycotoxins,” says Cary B. Sifferath, China senior director, U.S. Grains Council. “But they could change this in the future. If they do start to check for various mycotoxins, some believe they would use U.S. FDA acceptable levels for various mycotoxins.”

Generally, U.S. DDGS has fewer occurrences of toxins than domestic Chinese DDGS, due in part to the accurate and reliable testing methods employed by ethanol facilities in the United States.

Testing for mycotoxins is usually done on the corn at the bulk receiving points before it is processed into ethanol and DDGS. There is a variety of ways a company can test for toxins, and test strips are one of those convenient methods.

Simon Varney, product manager for agriculture products, Envirologix, a developer of the immunoassay diagnostic test kit method, says speed and ease-of-use makes test strips a popular choice for analyzing toxin levels.

“We provide fast, simple and accurate test strips that detect toxins at required industry levels,” says Varney. “These are on-site, easy-to-use tests that typically require grinding a sample and extracting the toxin with a solvent or tap water. The tests themselves are immunoassays or, basically, antibody-based protein tests — much like a common pregnancy test. When used with our QuickScan reader system, customers can quantify and track test results for aflatoxin, deoxynivalenol (DON) and fumonisin.”

Some of Envirologix’s test strips allow users to utilize the same sample extract to detect multiple toxins, which saves on sample-preparation time spent grinding. The QuickScan system also allows customers to quantify up to three different toxins or four of the same different mycotoxins at once.

The ELISA, or enzyme-linked immunosorbent assay, analytical method is another option for ethanol plants. The sampling process is similar to what is required when using test strips; however, the liquid sample is transferred into an antibody-coated well, where it will turn colors to indicate the presence of toxins.

Neogen, a manufacturer of analytical tools for the feed and grain industry, makes ELISA test kits for a variety of toxins. Paul Pfeiffer, territory manager, milling and grain, Neogen, says one advantage of the ELISA method of testing is its versatility. Since most ELISA tests work the same way, with the same volumes, once someone learns to use one type of toxin test, they can apply that knowledge to Neogen’s other toxin tests.

“For example we’re seeing the presence of DON in corn this year because the weather was cool and wet in many areas,” says Pfeiffer. “Many corn processors are used to testing only for aflatoxin or fumonison, but if they have been trained with our Veratox tests for aflatoxin and fumonison, they already know how to conduct the testing for DON.”

After testing the corn for toxins at the receiving locations, many ethanol facilities send samples of DDGS to analytical labs for third-party testing of the finished co-product.

Trilogy Analytical Laboratory has been testing DDGS using the high-pressure liquid chromatography, or HPLC, instrumentation method for 10 years. According to Carrie Maune, president, Trilogy Analytical Laboratory, the HPLC method of testing is ideal for testing more complex feeds, such as DDGS, while other methods are ideal for simpler subjects, like corn.

HPLC analytical instruments are complex, sophisticated pieces of equipment, and require a trained lab technician to operate. Many ethanol facilities that have an HPLC analyzer in their testing lab also send DDGS samples in to be analyzed about once a month. This measure contributes to quality control and gives customers peace of mind that a source other than their supplier verifies the safety of the product.

“HPLC instrumentation can also be used as a ‘referee’ when two or more tests show conflicting results,” says Maune. “The HPLC instrumentation results are generally viewed as higher quality and more accurate.”

Quality counts
Testing certainly helps reassure customers they’re getting a quality product, but for the most part, many Chinese importers buy U.S. DDGS because they already believe it is a higher quality product than domestic Chinese DDGS.

Jason Song, president, Gentech Co., owns a large specialty feed company headquartered in Shanghai, China. Song says many of his poultry, beef and dairy customers find U.S. DDGS to be an economical and high-quality alternative to higher priced protein options.

But their motives behind choosing U.S. DDGS over domestic Chinese DDGS are not purely financially driven. Song attributes China’s rise in U.S. DDGS imports to the consistency of the product, due to the quality control measures taken during processing.

“In China, the domestic DDGS is mainly a byproduct of liquor production, not ethanol, which is really a different product and not very consistent,” says Song. “There are not many consistent specifications or quality control measures taken in China, like what is done in the United States.”

Shadow believes that a decrease in ethanol subsidies may have lead to an increase in U.S. DDGS quality control.

“Now that some subsidies are no longer in place, ethanol producers are looking more into how to improve the efficiency of their processing,” says Shadow. “An efficient, consistent process creates a consistent co-product. DDGS importers will continue to buy if they can consistently receive the same product and reduce the need to reformulate. Through testing you’re able to increase the efficiency of the ethanol plant and the co-product quality and consistency.”

Ethanol plants in the United States have embraced the concept of quality control. Whether testing for protein, fat, fiber, moisture or toxins, characterizing and quantifying each of those components has helped deliver customer satisfaction across the globe.