from the wall, reducing the possibility of it brushing against a contaminated surface.
However, there isn’t a universally accepted scientific answer proving that one orientation is always more hygienic.
In fact, microbiologist Primrose Freestone has argued that under may sometimes reduce contamination of the roll because users can pull and tear the paper with one hand without touching as much of the roll. Other experts disagree with that reasoning and point to the possibility of touching the wall when the paper hangs underneath.
So the “scientifically proven correct way” claim
