To put a cool pack in a lunchbox?

[Purrloin]

DS is currently taking packed lunches to school, usually consisting of a sandwich, yoghurt, crisps and fruit.

I always put in a cool (freezer) pack to try and keep it all cool, particularly the yoghurt and the ham or cheese that he usually has in his sandwich.

Clearly ExH thinks I am bonkers, as he now has a nice little collection of my cool packs building up at his house and doesn’t put them in when it’s his turn to make the packed lunch when DS is staying with him.

So AIBU to put one in? Surely you are at risk of bacteria growing if things are kept at the wrong temperature?

Oh, and get ExH to give them back! The thieving bastard

I freeze a tube or pouch yoghurt. Then put it in in the morning. It stays cold and keeps the lunch cold but defrosts by lunch time.

I put one in my DDs lunchbag every day