On Wed, 6 Dec 2017 22:01:13 -0800, Julie Bove wrote:

> Keep it and roast it on Xmas day? Keep it and eat it cold?

Either would be safe. Ham is already cured with salt & sugar; both prevent
bacterial growth. If you are not sure, roast it again as you suggested.
That way, even if there was a small amount of bacterial growth while it
warmed-up the one time the fridge was open, roasting will kill that off.

Note: If you ever have meat that has obviously become spoiled
(discolouration, fetid odour, liquidized putrefication), complete cooking
will kill all bacteria BUT DOES NOT make it safe. In such a case, anerobic
bacteria will have created dangerous toxins that cannot be neutralized by
any amount of cooking. This is not the case with a ham warmed-up for a day.