Sounds to me like throwing food on the floor gets a reaction from you.
This isn't exactly the same, but maybe you can see my point.
I had a friend whose little girl would throw her bowl on the floor when she wanted to get down. Every time (I am SO consistent, the mom complained) she was put in time out for 2 minutes, then allowed to go play. I pointed out that it worked. She was punished for throwing her bowl, but she knew (thanks to Mom's consistency) that she would serve her 2 minutes and then run off to play. The trade off was worth it to her. I suggested that when she threw the bowl, Mom put it back on the high chair, and told the little girl to say, "Down please." And repeat it until effort (not perfection) was made at a verbal request to get down. She had taught her little girl that throwing her bowl on the floor was the way to get down. She had to teach her what TO do to replace that behavior.
Whenever I have a continuing behavior with my kids, and I feel like I've addressed it up and down, but it won't go away, I just sit and think about what I am doing to CAUSE them to behave that way. Something I am doing is teaching them to respond that way, in spite of all my instruction.
So, does the world stop while you clean up the mess? Does he get one on one attention (even negative) after he throws food? Do all the grownups stop talking and look at him? Do you give in to what he wanted? Or do you give him something else? Because if you do, he is simply paying for something, anything (not even necessarily what he wanted) by throwing food down and getting a lecture or whatever.
So, I would:
1.) Not give him a rise at all for that behavior.
2.) Hardly look his direction as I say, "Go pick that up." "Or, get a washcloth and wipe the floor."
3.) After the next offense, tell him that food will only be allowed at the table.
4.) Even if he throws his food on the floor, he will not be excused until I am done eating. And then he can clean it up before he goes to play. I would calmly sit and eat and ignore him. Except to say, "Remember, there will not be any more food until breakfast. And you will clean up your messes."
I am also a big fan of redoing a scenerio. So, he got mad about his underwear and threw the plum. Fine. We go get the plum, and I give it back to him. "Mama, please help me with my underwear." "Mama, may I please wear the other color". Whatever. So, we repeat the scenerio UNTIL he does it nicely and not grudging. And without throwing the plum. Yes, it can get exhausting. But I'd rather deal with it for 3 hours this morning than for the next 6 months. It's less stressful for everyone that way. He can get what he wants...and I can, too.
He's not quite 3, I know. But I have a 33mo old (and 2 older, and 1 younger), and she is totally capable of getting a washcloth out of the drawer, taking it to the bathroom to get it wet, and cleaning up a mess. And she is totally capable on not throwing stuff when she is angry. :)