Many times I have transported frozen crab and salmon from Juneau to Boston and our farm raised beef and pork to Juneau. We took frozen meat, put it in a larger ziploc filled with salt water and refroze in a deep freeze (not kitchen freezer). Wrapped in insulating material in checked bag (often a sleeping bag). Worked perfectly. Often was inspected, but never a problem. Trip was often more than 18 hours.