I have read, or maybe it was in the Fluoride Deception video, or one of the other videos provided by this forum, that the Iodine was taken out of the bread in the late 1960s. This information was somewhere around the info about when Breast Cancer began to increase.
As for replacing the Iodine immediately with bromide... I don't know that that was an immediate transference, or if it was an eventual thing that happened.