i have worked in a supermarket for years, and searched many times. I am usually asked to empty my handbag and all my pockets. Never at anytime has anyone phyically touched me. If the security person is a man, then there is always a woman member of staff present.
I am usually asked if I also want a personal representative of my choice with me during the search. I also have to sign a form saying I have agreed to be searched.
The searches are random, and no one takes them personally.