Another quiz

Alright. It is time for the answer to the Buka Buka question. We got a few responses like, "it's a flower" or "a fertilizer" but no one guessed that Buka Buka is.....a type of fish. Zambians sell this fish dried to a crisp, cook it in oil until it is soft and eat it.
So what do missionaries do when they are tired of discussing difficult subjects? They talk about trivial things! This came up recently, what is this kitchen item called that separates water from food? You can answer in the comment section.