Parsing an RSS item that has a colon in the tag with Ruby?

I'm trying to parse the info from an RSS feed that has this tag structure:

<dc:subject>foo bar</dc:subject>

using the built in Ruby RSS library. Obviously, doing item.dc:subject is throwing errors, but I can't figure out any way to pull out that info. Is there any way to get this to work? Or is it possible with a different RSS library?