It has been a few years since I had AP U.S. History, but I recall reading in my textbook that the Aztecs, as a way of getting back at the Spanish, baked blood that was contaminated with diseases (most notably syphilis) into bread they made for the Spaniards. I was trying to find some evidence of this online, but I was not able to do so. Is this something the authors just made up, or is this just something that doesn't exist on the Internet for whatever reason?
The answer here is no. They did not bake bread. Most of their preparations for corn were unleavened - tortillas, huaraches, tamales, etc. They also did not have a conception of germ theory or blood borne illness - neither did the Spanish, for that matter.