1574 Research Article Received: 6 January 2009 Revised: 1 April 2009 Accepted: 3 April 2009 Published online in Wiley Interscience: 20 May 2009 (www.interscience.wiley.com) DOI 10.1002/jsfa.3626 Mycotoxins in fuel ethanol co-products derived from maize: a mass balance for deoxynivalenol Arthur W Schaafsma, a* Victor Limay-Rios, a Diane E Paul a and J David Miller b Abstract BACKGROUND: Three matrices – corn (maize) meal, distiller’s dried grains with solubles (DDGS) and condensed distiller’s solubles (CDS) – were sampled in sequence from a continuous dry-milling process plant for the determination of mass balance of deoxynivalenol (DON). Four commercially available enzyme-linked immunosorbent assay (ELISA) kits were evaluated for their ability to measure the presence of DON. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) was used as standard method to detect DON and other Fusarium toxins. RESULTS: The concentrations of DON in DDGS and especially CDS were overestimated or underestimated by ELISA. However, for both matrices, all ELISA methods were not significantly different in their mean results from the LC/MS/MS standard, although the variability in results was much higher. DON concentrations in the CDS and the final DDGS co-product were significantly higher (P ≤ 0.01) than in the starting material (corn grain). Toxin concentration increased by a factor of 3 on a dry weight basis in DDGS compared with the starting corn and by a factor of 4 in CDS. Mean concentration of DON in CDS was four times higher (7.11 mg kg -1 ) than in corn grains (1.80 mg kg -1 ) and 1.4 times higher than in DDGS (5.24 mg kg -1 ). Mass balance calculations showed that CDS was the main source of contamination of DON, comprising ca 70% of the toxin found in the final product (DDGS). Most DON (87%) was accounted for by this analysis. CONCLUSION: Concentrations in the grain corn entering ethanol plants should be close to the dietary values recommended for swine in Canada and the USA for DON (1 mg kg -1 ). Small amounts of acetyldeoxynivalenol and DON glucoside were also found in the three matrices along with a small amount of zearalenone. Unlike the situation for DON, the DON glucoside was not concentrated into DDGS and CDS, indicating that it was hydrolysed during the fermentation process. c  2009 Society of Chemical Industry Keywords: commercial ethanol; corn (maize); deoxynivalenol; distiller’s grain solids; ELISA; LC/MS/MS INTRODUCTION Canadian ethanol production capacity is projected to approach 3 GL by the end of 2010. 1 At the time of writing, ca 1.0 Mt of corn and 0.5 Mt of wheat are used to produce 0.7 GL of ethanol. The Canadian government has set a production target of 2.74 GL of ethanol by 2010. The USA produces approximately 26 GL, with large increases expected over the next decade. 2 Corn (maize) can be converted into ethanol by either wet milling or dry grind processing. The dry grind process is more cost-effective and common, although better system designs are required. After the corn has been ground, enzymes are added to break down the starch to fermentable sugars, but without fractionation of kernel components (endosperm, germ or bran). The residue remaining after distillation is processed further by a series of dewatering and drying steps to produce distiller’s dried grains with solubles (DDGS) and small amounts of wet grains and condensed distiller’s (syrup) solubles (CDS). 3 Typically, each unit mass of corn produces approximately equal proportions of ethanol, carbon dioxide and DDGS. By the year 2010, production of DDGS in Canada is expected to reach 2.1 Mt. 1 This co-product can provide an affordable source of protein and energy to animal feed rations. DDGS is fed mainly to dairy cows 4 and beef cattle 5 but also to swine 6 and poultry 7 for protein and fibre. Using and adding value to this co-product may be essential to the sustainability of the fuel ethanol business. 3,8 – 10 As fuel ethanol became of interest in the USA and Canada at the time of the first energy crisis in the 1970s, large investments were made in biomass energy. 11,12 Early problems identified for cereal-based co- products of ethanol production included variable nutrient quality, making the development of acceptable dietary incorporation rates difficult, as well as storage problems of distiller’s grain solids for feed, notably difficulties with mycotoxin contamination. Another problem identified early on was the potential for mycotoxins to affect ethanol productivity of yeasts. 13–15 In northern temperate areas such as Ontario, contamination by toxins from Fusarium graminearum, particularly deoxynivalenol (DON) and zearalenone, is common. There is also some contribu- tion by fumonisin, but so far this has been modest in comparison with other corn-producing areas. 16,17 In recent years, DON has been most common. 16,18 Zearalenone was more common 30 years ∗ Correspondence to: Arthur W Schaafsma, University of Guelph, Ridgetown Campus, Ridgetown, Ontario N0P 2C0, Canada. E-mail: aschaafs@ridgetownc.uoguelph.ca a University of Guelph, Ridgetown Campus, Ridgetown, Ontario N0P 2C0, Canada b Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada J Sci Food Agric 2009; 89: 1574–1580 www.soci.org c  2009 Society of Chemical Industry