E.
I find that the concentrated Tide (it says 2X on the jug and is smallish but can wash 100 loads) added right to the stain, scrubbed in, then washed in more Tide gets out just about anything. However, why not alleviate the problem at the start? Maybe buy a larger T-shirt at Goodwill or as a hand-me-down from a friend or neighbor. Decorate with appliques of food or use fabric markers to draw some. Pack it with her stuff for the babysitter and make it her "eating" shirt. Just put it on over her clothes and let her eat her way. You can get a pack of 3-4 T-shirts from Walmart for cheap and then she would be all set no matter what.