Risa

The food replicators converted energy directly into food the same way transporters convert a person from matter into energy and then back again. What he was describing was a completely different type of process likely mechanical and chemical in nature.

Note he did not say one of the things they turned waste into was food.

Edit: IIRC they actually had an episode of Enterprise in which they encountered an alien race that had food replicators and were fascinated by the technology.