Prolonging meat life for packing out
I'm planning a hunt this spring in the mountains in the south island of New Zealand, and am hoping to shoot a red deer for the freezer. The area that I am planning on going to is very very remote, and aircraft landing is not permitted, so it's a case of walking in, doing the business and walking out. The walk out will take 2 days at normal tramping/hiking walking speeds. Some of the walk will be at alpine altitude (crossing mountains), but most of it will be below 1000m above sea level. Temperatures at that time of the year would be between 18-25 deg C.
I normally cut the meat off the carcass once it has cooled and pack the meat out (without the bones) and then butcher the meat at home. Because of the long walk out, I am concerned about the meat going off, and was wondering what you guys suggest in order to prolong the meat life. I was thinking of using zip-vac bags to remove the air for around the meat and packing it in 1-2 kg packs.
Once out of the mountains, I still have to get a flight home, from the nearest town, but I will be able to re-pack the meat in ice for the flight, so that should not be too much of a problem.
Any suggestions on how to prolong the life of the meat, or on how much time I would have before the meat starts turning bad?