Personally, I say: Not freaking ever at all, forever throughout the universe.
Mom is allergic to peppers: bell, jalapeno etc. So we will not touch any food sample without reading the back of the box.
Anyone with allergies will prefer to confirm for themselves than trust their lives in the hands of someone who doesn't know or understand the potential dangers. No one has ever objected to my picking up an empty box at the sampling station; we are in no way endangering the food, and we explain it directly to the person we are interacting with.
Till one lady decided that it wasn't allowable due to 'health code reasons,' and when I asked her to read the box to us, she just gave it a cursory glance and said there were no peppers.
When I told her that I needed to actually read the box myself, since she didn't do as I asked, she got all offended and angry at me.
Then she got all huffy at me because I basically proved that she was a liar, and refused/defied/undermined/whatever her authority by picking up the box myself even when she tried the 'health codes said no, and they mean NO" at me.
1) I am not putting my hands near the food: the empty box was on top of your microwave.
2) I do not trust YOU with my mother's health if that's the way you 'check' for allergens.
3) Fuck you with a cactus! THERE ARE DRIED CHILI PEPPERS IN THAT FOOD PRODUCT, IT SAYS SO RIGHT FUCKING THERE!
4) Health codes say nothing about what I'm doing so get the fuck over yourself.
Bad retail slaves give us all a bad name. Too bad this is a while ago so I can't complain. I really am too fucking patient with bad retail slaves.