I looked at observations of rough-skinned newts the other day and noticed quite a few had pictures of these animals being handled without any sort of protective gloves. The ‘about’ page for rough-skinned newts (and other species of Taricha) says that they secrete tetrodotoxin from their skins. This is the same toxin found in fugu, and can be deadly when ingested, even in very small quantities. Obviously, the people handling the newts are not eating them, but are they taking a big risk by touching them without gloves? Is there a danger from the toxin transferring from their hands to their food or to more sensitive areas such as the eyes?
Growing up with them it was never a problem (for the humans) handling them. As a kid the adults would remind us to wash our hands after, but even if we didn’t no-one ever had any reaction at all.
The toxin is not constantly present either, it’s released when they’re feeling threatened. If you’re careful and gentle they are unlikely to release it, at least in my experience.
For humans, washing your hands after should be good enough to prevent any possibility of harm.
There are lots of good reasons not to handle them, but that’s more for the health of the animal, and it’s best if observers don’t handle animals as a general principle (although there are, of course, exceptions on a case-by-case basis).