The food is sealed with special machine and probably available at Walmart as bags are. Bags can come in Pre made bags (1 end already sealed) or roll where cut and seal end, making size bags you need.
Once I make burgers(seasoned), I place in freezer to let harden before vac-packing so that the vac-pack process does not further flatten/distort. Filets, chicken, fish, etc.

We can take a week worth of meat/cheese for 6 people (eat out every other night) in a 24 can cooler. Sometimes take 2 coolers for 2 weeks food. I have not tried the 48 can but knew many concerned about weight when loaded.

Re: Dry Ice, had less than 5 pounds (which is the limit per person) and TSA never blinked an eye. Went through X-ray machine and no issues or questions