by flingebunt » Sat 12 Jan, 2019 11:25 am
Freeze dried product last a very long time. The pre-packed products are vacuum sealed in a sterilised foil containers in a nitrogen environment, which means they can last for up to 20 years. Freeze dried fruits often only have a shelf life of 2 years.
Once you open them they exposed to air, water and contaminants. My understanding is that the real enemy is water. If you are in a humid climate, your freeze dried products will last less time once opened than in a desert.
Having said that, 6 months is a good rule of thumb for products that would stay good unopened for 20 years. If they are in sealed plastic bags they should easily last the length of most hikes. You probably don't want to open them, take the food you want, and then try to store the rest of the food for too long. Though if sealed back up properly and stored in a freezer, it should be good.
If they get wet or even damp though, it should be a case of eat them right away.
This means that opening them and repacking them before hiking is the best way to go. You can also open the packet, eat what you want, then put the rest away, could have dangers, such as if it gets moist from rain or damp air.