We had Benson Lab at BYU do a small evaluation on some dehydrated food that was on average, 28 years old. This food was stored about 58 degrees F. The average oxygen percentage was 8.62%. Ratings according to the following scale were used for grading:
5 = Excellent 3 = Satisfactory 1 = unsatisfactory
4 = Good 2 = Minimum passing
Headspace Overall
Product % Oxygen Appearance Flavor Aroma Texture Rating
Veg Soup 9.0 3 4 4 4 3
Corn 0.292 3 3 4 2 3
Oats 2.3 4 4 4 4 4
Eggs 2.85 2 2 2 3 2
Dry Milk 20.85 4 4 4 4 4
Milk Solids 20.45 4 4 4 4 4
Butter Powder 4.6 3 3 3 3 3Alan Wright from Benson Lab, BYU, wrote, "These evaluations are based solely on the products present (after storage) attributes. We did not compare these products against freshly produced counterparts. They were compared with basic standards of food quality. Considering the time period of storage, the products have stored very well (better than many stored that long, i.e. 7 November 1964, 11 August 1967, and 25 July 1970). Most certainly the storage conditions (reduced temperature and reduced oxygen) contributed to this. In general, the products are good and worthy of use. The egg powder would best be used as an ingredient rather than a food itself."
With our present packing methods reducing oxygen content to .05%, storage life of present products should be even further enhanced.