To summarize the study in question:
A dough made with flour that has a bromate quantitiy of 10 ppm retains 3.84 ppm bromate after five minutes of baking at 220C (428F). A dough made with flour that has a bromate quantity of 20 ppm retains 11.01 ppm bromate after five minutes of baking at 220C (428F). Beyond five minutes of baking, there is zero.
General Mills bromated flours contain 8-16 ppm bromate.
This study by Bushuk and Hlynka contradicts an earlier study by Lee and Tkachuk that found greater quantities of residual bromate in baked dough. When given the opportunity to respond, Lee and Tkachuk confirmed the later study, and admitted their error in an addendum.
This study says nothing about sub five minute bakes at temperatures higher than 428F. I'd like to see one.
Cookbooks are directed to ordinary people, and publishers won't let authors publish books that call for ingredients that ordinary consumers cannot find at their local supermarkets.
Diastatic malt is available at Kroger?