Messenger of Allah (ﷺ) said, "Satan appears at every thing done by you; he appears even at one's dinner. When a morsel of any of you falls, he should pick it up and remove any dirt on it, and then eat it. He should not leave it for Satan, nor should he wipe his hand with the towel until he has licked his fingers, for he does not know in what portion of the food the blessing lies."

[Muslim].