Does an R in O mean a food is kosher?

No, an "R" in a circle does not mean a food is kosher.

The symbol you're describing is the "R" in a circle, which stands for Registered Trademark. It indicates that a product or brand name is legally registered.

Kosher symbols are different and are typically:

* A "K" in a circle for kosher certification.

* Other symbols specific to different kosher certifying agencies.

You can learn more about kosher certification symbols by visiting the websites of reputable kosher organizations like the Orthodox Union (OU) or the Star-K.