I think it is a good idea to mention it to your manager.That person can bring it up now at the mettings, and advise all employees to lock their personal possesions up.Like many places there is probably a clause in work rules that states they are not responsible for lost or stolen items. It is to bad this occured,because now you will always question/wonder who could have stolen from you.Work just won't be the same place it was.Atleast it was a smaller loss....though $20 is a lot of food for me!