Had a similar incident happen at our hospital a year or so ago. We have two semi-tame cats that live at our hospital. They are normally kinda skittish with new people anyways but with the staff they are fairly calm. Someone bought a new bag of food for them specifically for 'indoor' cats to keep them from gaining too much weight. The new food had red and yellow dyes in it. Shortly after we started feeding it to them they started getting really jumpy even with the staff. They got to the point we could no longer pet or hold them anymore, basically back to the way they had been several years earlier when they first came to us. We figured it had to be the food because we couldn't find any other reason for the behaviour. About a week after getting them switched back to their normal food the skittish behaviour with the staff, dissapeared and we could pet and hold them again.

Yes I fully believe that food can cause behaviour problems, and this was yet another reason I hate foods with lots of dyes in them.