It did, and eating by mouth is also an option for MU beings, but they tend to prefer the hand method, as chewing food orally is considered disgusting to them. It's possible that the herb needed to be consumed orally to dispense its antidote. Additionally, Nokama also used her mouth to taste the water surrounding Mata Nui when they first explored the island (she didn't like it much).
As a fun side note, I've always headcanoned that a reason why Matoran dislike Skakdi is that they have such large teeth, and that they only eat with their mouths, making them even more repellant to other beings.
