If you look at the side you can see that the nutrition fact label is not the new style introduced in the 90s.
A few years back I remembered hearing about old mixes being dangerous to eat so I checked it out on snopes. It looks as if it can be dangerous if mold grows in the flour. This can happen if the flour is kept loose in the box or in plain paper envelopes. Taking their advice I investigated further to see how the flour was packaged.
I just love those fancy 80s graphics!!!!
Unfortunately these were just in plain paper wrappings and smelled like basement (makes sense since they have been in the basment for 20 years).
Oh well, I guess they're off to the trash! Now I really want some angel food cake.....