What happens if food is stuck in your mouth when performing wudhu and you cant get rid of it from your mouth...??

Salaams... Just say one has eaten and goes out to perform salaat with jamaat. After he performs wudhu he realizes that there is still food stuck in his mouth. Does he have to go and clean his mouth before praying. What if he started salaat and then only realizes this..is his salaat still valid. Im asking because i am aware that every part of your mouth has to be washed with water for wudhu to be valid and what happens if you have a problem like the one i mentioned above..?? Jazakallah