Just make sure you keep all the food in sealable bags/containers, and don't ever leave them open on the stroller, in the diaper bag, or leave any juice boxes/sippy cups on the stroller where animals can get to them. I've seen birds and squirrels on strollers having a feast while people are inside attractions.
We always bring snacks. I just make sure I have lots of ziplock bags & I zip the diaper bag up completely, too!