Excellent idea - at least 1 litre can be stored in the glove box. Maybe I can round up Mainstay pacs and throw them in there and a container under the seats (fixed so that it doesn't shift around)

I is not safe to eat frozen can goods unless it has just recently and only once been frozen and then consumed.

http://www.foodsafetyline.org/english/canned_faq.html