Dried herbs and spices - Effect on shelf life?

[Firelover123]

been looking at making up some hardtack (water flour salt, basically a rock hard cracker) normally this stuff last for well over a year but I was considering adding some dried herb to the mix to flavour it up as its mainly used to bulk out soups etc. ive been told cinnamon degrades the shelf life loads. been looking at nutmeg, pepper, garlic powder. anyone know the effect those three would have?

[DundeePrepper]

I've never heard of cinnamon reducing shelf life?

I just came across and posted a link to this website a minute ago.. http://www.eatbydate.com/

and there is a bit about spices, specifically on cinnamon

http://www.eatbydate.com/other/spices/h ... tion-date/

Hope this helps