Its true that we can preserve foods and also Medicines in the Pyramid
as i shown in the video pyramid has maximum energy in its Kings Chamber, to be clear Kings Chamber is the area present exactly at the middle from Apex to Base,

You know that pyramids are constructed to preserve dead bodies other wise called Mummies, till today body of the mummies are not spoiled much they have intact hair and nails also. so correlate this issue to preserve food, finally my conclusion is u can store food for long time, if u place them in correct position in the Pyramid they spoil for a long time.