Fate of dwarf bunt fungus teliospores during milling of wheat into flour

Wheat contaminated with teliospores of Tilletia controversa Kuhn (TCK) was mixed with uncontaminated wheat and processed through the Kansas State Univ ersity pilot mill. Two SD-bu lots of the contaminated mixture were cleaned, tempered, and milled. Approximately 500 samples of wheat, cleanings, and m ill fractions were collected and examined for the presence of intact and br oken TCK teliospores. Whole wheat samples (50 g) were washed, sieved throug h a 60-mu m nylon sieve, and pelleted by centrifugation. Contents of the pe llet were examined microscopically for the presence of TCK spores. The proc edure was modified as needed to accommodate cleanings and mill fractions. L evels of spore contamination in whole wheat samples decreased at each step during the handling process, and large numbers of spores were found in mate rials that were sieved or aspirated from the grain. Very few spores were fo und in bran, germ, and shorts; none were detected in red dog or straight-gr ade flour. The results showed that a high percentage of spores can be remov ed from wheat by mechanical cleaning but that it is not feasible to remove all of them.