Here is some helpful advice from Rebecca Newberry of the Science Museum of Minnesota:
“Is the box shrink wrapped? Or just the bag of cereal? What kind of cereal–just grain based or something with dried fruit or nuts? Can they access the inside of the box easily? Is it still factory sealed?
I would think if the cereal is just grain based (like Wheaties) and is still sealed in the original plastic bag and it the plastic looks stable, it should be fine. I would be concerned about cereal in a waxed paper bag since it would be more vulnerable to insect infestation. Cereal with fruits and or nuts would be more likely to deteriorate or react with the original packaging.
Keeping the box in a cabinet would reduce the risk of mouse and insect infestation. Of course, you’d want to be careful about sealing the box into something too air tight since I’m guessing the cardboard isn’t super high quality and will break down faster without ventilation.
Basically, keep it dry, keep it away from pests and it should last a long time. If the contents aren’t vital, a paper conservator could open the box, remove the contents and seal the box back up.”
Rebecca also added that she will be covering food stored in collections in a webinar with Fran Ritchie and Bethany Palumbo this fall.
I hope that helps!