This is a episode from SpongeKid Slightpants: Lunch Hour.
When the lunch lady is out sick, Planktons does the cooking while she is gone. He serves people chum and eventually a food fight is started.
Spongebob: Ewwww. What is this slop.
Squidward: (tastes it) It tastes like it came from the toilet.
Sandy: It's worse than the lunch lady's food! (vomits inside helment)
Kid: I'm sick of this crud! (throws it)
All Kids: FOOD FIGHT!!! (kids food fight)
Plankton: STTTTTOOOOOPPPP!!!!! (gets hit with chum then the kids stop food fighting)
Patrick: But I like throwing food. (throws chum at Plankton and food fight restarts)
Stanley Squarepants: (slips over chum and chum hits the wall and spells out "THE END")