Haven't watched episode 2 yet. On page 36. But regarding the bread/flour theory remember that Tommy was at a bar when "some dude started going crazy" and a fight broke out. Well we know beer is made of yeast which is a type of fungus.
The only issue becomes the use of liquor which Joel drinks, but in the show we only see him drink liquor when using hydros (not sure if that's done purposely).
So it's probably not yeast causing the situation or mabe it is. But if it is, then going west into the bread basket of the country is one stuuupid fukkn idea lol (I know he doesn't know).