Translation:Do not put the finger in the mouth because it is full of bacteria!
Maybe, by mistake, they forgot about "pentru" or it's just another way to say "because". Could someone explain it?
"Că" comes from "pentru că" It is a shorter way of saying,though not that correct, but still used.
which - the finger or the mouth? "Full" seems to suggest the mouth, but I guess that this is not what is intended
The Romanian sentence uses "plin", which is masculine and, thus, unambiguously refers to "degetul". Although its most immediate English translation is "full", "plin" can also be referred to surfaces to mean that they are "completely covered with something" or figuratively to mean that "there is plenty of something" (in this context, both meanings apply).