AFIA releases DDGS reports, recommendations and guidelines
The American Feed Industry Association (AFIA) released a year-long study on distillers dried grains with solubles (DDGS) analytical methodologies and DDGS ingredient guidelines along with guidelines for condensed distiller solubles. Over 60 industry representatives from 40 AFIA member companies participated in the landmark initiative.
The recommendations resulted from concern by purchasers and suppliers of ethanol co-products over a lack of mutual agreement on of DDGS analytical methodologies.
DDGS producers claimed that the most frequent methods utilized provide differing estimates of the nutrient values for moisture and crude fat.
Working with the Renewable Fuels Association (RFA) and the National Corn Growers Association (NCGA), funds were committed to contract with the Olsen Biochemistry Laboratory of South Dakota State University for two purposes (1) to examine common analytical methods utilized in the marketplace and (2) to conduct both intra-laboratory and inter-laboratory studies on which methods provided the best estimates of those nutrients.
The study was expanded to include crude protein and crude fiber assays. Nancy Thiex, chair of the Association of American Feed Control Officials (AAFCO) Laboratory Methods and Services Committee, served as study director.
Under the study, DDGS samples were collected from six facilities and utilized for comparison of 13 methods among four nutrient components (moisture, fat, fiber and protein).
These methods were found the most commonly used in the marketplace. Of concern was the use of different methods by the purchaser and supplier that frequently would provide differing estimates of the true nutrient value. One firm discovered over 3% variation in moisture by four different “loss on drying” methods.
The most common method used to determine moisture actually determines any material that evaporates on drying the DDGS product. At higher temperatures and longer drying times, it’s clear that more than moisture can evaporate, providing a false value.
The only method recognized for actual moisture measurement, the Karl Fischer Method, is not likely to be used in daily trade due to the high cost of equipment. All other moisture methods are based on heating/drying for specified times and temperatures. These provide an indirect measure of the water contained in a tested product, “known as loss on drying.”
The study found five analytical methods from the 13 evaluated that provided the best estimates for moisture (one method from National Forage Testing Association, NFTA 2.2.2.5), crude protein (two nearly equivalent methods, both from AOAC International, AOAC 990.03 and AOAC 2001.11), crude fat (one method using AOAC 945.16) and crude fiber (one method, AOAC 978.10). A nearly equivalent crude fiber method was deemed problematic due to the unavailability of essential equipment used in the testing.
AFIA and the other co-sponsors plan to widely distribute its report and recommendations. Although other alternatives exist, these method guidelines are based on a valid scientific study.
A second report deals with how AFIA describes ethanol co-product ingredients to the industry and public from AFIA’s Electronic Feed Ingredient Guide (E-FIG).
The working group dealing with this issue recommended some changes to two ingredient guidelines AFIA developed many years ago.
Suggested changes bring the guidelines in line with recent industry developments and describe these two ingredients in a realistic current-time fashion.
Nonetheless, these ingredient guidelines may still be frequently modified and additional ones developed to meet ongoing needs of this dynamic industry.
For copies of these reports and recommendations, contact AFIA VP, Richard Sellers.
Read more in the latest issue of Feed Technology Update (PDF)
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