Spitting out food - yeuch

My DS who is 21 months old is spitting out food. Not doing it the whole time and doesn't seem to be any particular type or texture of food that makes him do it. Sometimes he'll spit it out the minute it goes in other times he chew for a while and then spit out. I'm not worried about whether he's eating enough or not but its just a bit gross especially if we are out when he does it.

Any suggestions on anything that can be done to stop him doing it. I've tried telling him no spitting food but he just gives me this look - as if to say yeah whatever Mummy! Don't think he does it when he is at day care as the girls haven't mentioned it to me so could be pushing my buttons perhaps?

Any thoughts?

Has he got teeth coming? Pixie was doing this when she had 2 canines and a 2 year old trying to come through. I think it depended on how her teeth were feeling as to whether she'd want that particular food or not. Some days even a touch of juice from her apple or even bread were painful for her to eat

Both my kids have done it. I never found anything that worked to prevent it. It passed, like all things. Nate was particularly bad at it and still does it on occasion. If he wanted an apple he had to eat it outside....saved me some time lol.
When we're out I try to just be discreet. Yep it's yuck but I figure it could be far worse. It's kind of random for him so I figure it's a particular sensation on a particular day.

We take DS' food off him if he does that. Best not to make a fuss about it (that just encourages them :)) - we just have a rule that you eat food, not play with it. If he's playing, the food gets taken away.

Thanks ladies. CrazyLady he still has to get his 2 year molars but don't think they're on the move at the moment as none of the other signs of horrid teething episode approaching are showing so don't think that the cause at the moment. Guess I'll just try ignoring the behaviour when he does it the next few times and see if he gets bored with it as he won't be getting any additional attention!