As you can see from the rows of jars in the supermarket and the bins of packets in the fast food stops, mayo does not require refrigeration...until the package is opened.

<img src="/forums/images/graemlins/tongue.gif" alt="" /> (bangs head on desk) Yeah, I'm not quite sure why that didn't occur to me - doh! I guess it's just that I've always seen them packaged in with things that are refrigerated...