Yoghurt

Yoghurt was a dairy product, sometimes flavoured, found on Earth.

After being killed by Guy Wildman, the consistency of Jennifer Fallon's skull reminded Gwen Cooper of strawberry yoghurt. (PROSE: Another Life)

After the Eleventh Doctor regenerated he demanded yoghurt from Amelia Pond, declaring it his favourite. After eating it he spat it out in disgust, declaring that he hated it. (TV: The Eleventh Hour)

Years later, Amy threw out some yoghurt that had gone bad. (TV: The Power of Three)

Behind the scenes
The British division of Yoplait received a license in 2007 to market a Doctor Who-themed version of, their popular portable yoghurt range. Doctor Who Frubes thus came out at the start of series 3 — and promptly increased Yoplait's sales in that division by about a third. They used their license in 2008 for a second run.