So, as long as you're stuck with food to reinforce, how about getting away from requesting - that too tired, dead-end communication function.
You can do so much more at snack time than have kids make choices and requests for what they want to eat.
Kids often need help with opening containers or pushing straws into juice containers. They sometimes need to tell us they don’t like something (more appropriately than throwing it, that is), or that they want more of something, or something different. They might need to tell us that something fell on the floor. Or that little Johnny took something (over the years “little Johnny” has gotten a really bad rep).
A student might want to tell you this is his favorite or that this tastes yummy - or yucky. He might want to save some for later and need you to close it up.