Martin wrote:

Thanks for this. Have you heard of aluminium foil sealed covers for
plastic trays for frozen food? I've seen it for frozen pet fish food -
aluminium foil blister packaging. Any reasons not to do this for human
food?

Airlines do it all the time. Well, some of them have quit serving
food, but what you are describing sound like an airplane meal.

Bill Ranck
Blacksburg, Va.