Preventing backwash?

Is there a way to prevent it (aside from NOT DRINKING OUT OF THE JUICE CONTAINER STRAIGHT ON)?

Is there a way to prove or disprove if it happens, despite a certain person’s assurance that they don’t backwash, even accidentally, into the juice/milk/soda containers?

According to this site, “backwash” is very minimal:

mnmnn… I guess this means if I want no drinking from the carton I have to refrain from my uncivilised habit of nail biting, then.

Or have guests over often enough that such … liberties wouldn’t be taken by said party for fear of guests wanting to enjoy the same refreshments.

I thank you.

My Pop has a neat trick where he drinks from a container without letting it touch his lips. Guaranteed to be back-wash free.

Here’s a link to a fairly recent discussion on a similar topic:

Thanks. I did a search but got 0 results on that keyword, hrm?

Did you set the date parameter far enough back? (the default is ‘in the last day’)