What should one do if one began prayer having forgotten there was food in one's mouth? And is one's prayer invalidated if one keeps food such as chewing gum or a sweetie at the side of one's mouth without eating it?

If a worshiper enters prayer and remembers there is food in their mouth, it is disliked to keep it in the mouth due to their preoccupation with prayer, and they must remove it from their mouth. This action does not invalidate the prayer if it is slight and for a need. If the food is slight and descends with saliva without the intention of swallowing it, their prayer is not invalidated. However, if the retention of food leads to abandoning any of the obligatory recitations, such as Al-Fatiha, or if any part of it dissolves and is swallowed, their prayer is invalidated.