Originally Posted by Michel Gagnon
I use a thermal lunch box and small ice packs.
If I travel at 15-22 C and keep my lunch at my desk, using one ice pack is just ok to keep my lunch relatively cool until lunchtime. Two ice packs is safe enough for mayonnaise and other sensitive items, even when it's warm outside.
+1
Thats what I do. Two ice packs are good, and I always eat stuff like mayo, and tuna, and I've never had a problem, even on the hottest summer days.