what would happen to a person who stole food from a store but has not been arrested or turned him/herself in to the police?

The first thing to do is determine if there is a warrant for your arrest.  If there hasn't been a warrant issued and the items taken are valued at less than $200 and you don't have previous convictions for this offense, the statute of limitations to bring those warrants would be one year from the date of theft.  If the warrants have been issued, and they can prove that you took the items, then you are dealing with a mitigation case.  We have lot's of experience dealing with mitigation issues.  Feel free to contact my office.