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United States Department of Agriculture

Agricultural Research Service

Title: Fate of Dwarf Bunt Fungus (Tilletia Controversa Kuhn) Teliospores During Milling of Wheat into Flour

Authors
item Bechtel, Donald
item Wilson, Jeff
item Eustace, W - KANSS STATE UNIVERSITY
item Behnke, Keith - KANSAS STATE UNIVERSITY
item Whitaker, Thomas
item Peterson, Gary
item Sauer, David

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 29, 1998
Publication Date: N/A

Interpretive Summary: Wheat contaminated with dwarf bunt fungal teliospores of Tilletia controversa Kuhn (TCK) was mixed with non-contaminated hard red winter wheat and milled into flour. Most of the contaminating spores could be removed by the cleaning and milling operations. No spores were found in straight grade flour or the red dog mill fraction. Significantly, only 2.7 and 4.4% of the recoverable spores for the two mill runs were found in the germ, bran, and shorts fraction. The cleaning and tempering operations reduced the original contamination level by over 99%. Processing the mill-feed stream by extrusion killed all dwarf bunt spores present. The results showed that a high percentage of spores can be removed from wheat by mechanical cleaning and tempering.

Technical Abstract: Wheat contaminated with teliospores of Tilletia controversa Kuhn (TCK) was mixed with non-contaminated wheat and processed through the Kansas State University pilot mill. Two 50-bushel lots of the contaminated mixture were cleaned, tempered, and milled. Approximately 500 samples of wheat, cleanings, and mill fractions were collected and examined for the presence of intact and broken TCK teliospores. Whole wheat samples (50 g) were washed, sieved through a 60-um nylon sieve and pelleted by centrifuge. Contents of the pellet were examined for the presence of TCK spores microscopically. The procedure was modified as needed to accommodate cleanings and mill fractions. Samples of whole wheat decreased in spore contamination at each step in the handling process, and large numbers of spores were found in materials that were sieved or aspirated from the grain. Very few spores were found in bran, germ, and shorts; none were detected in red dog or straight-grade flour. The results showed that a high percentage of spores can be removed from wheat by mechanical cleaning but it is not feasible to remove all of them.

Last Modified: 7/24/2014
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