Shoprite
Searching of shopping bags at the exit/doo

I find it humiliating that a security guard opens my bags of grocery, move things around in my plastic as if I something while I just checked out at the till right in front of them. Shoprite must explain why is this happening. These security guys go for a smoke, go for a pee and they come back they hold my food and move it around in my shopping bags. Is that a legal procedure? Why this is not happening in all the other Shoprite stores???