A.M.
I was a director of a childcare for 4 years and this was something that happened more than you think. State Licensed centers are required to serve certain amount of portions of meat, fruit, veggies and have to stick to their menus if they do provide the food. This was something that new families to the center didn't understand because they wanted to bring in food that their child liked. Unless we had a doctor note, we could not provide substitutions.
This can be frustrating-I completely understand. You want to make sure they are eating. I found that after a few days, the child would begin to get comfortable in their environment and would begin eating with their friends. Now please do not take this the wrong way, but having the teachers give her special bars because she wouldn't eat could cause another problem-her knowing that she will get the bar if she doesn't eat the food at the center. I think it is a good idea if you are able to stop in for lunch at times just to see how she is doing. We always welcomed parents!
Hang in there, it is hard watching a child adjust to unfamiliar environments, but they will and it will get easier-just hang in there!