With 40 years of food use history, we expect propylene oxide will satisfy all the tests of availability, effectiveness, safety and practicality. Worldwide, over ten billion pounds of propylene oxide are produced annually. Propylene glycol is also the basis for the non-toxic Sierra antifreeze. The hydrolysis of propylene oxide to propylene glycol will be explored later. The total effectiveness of sterilization doses of propylene oxide against the pathogenic bacteria Salmonella and E. coli 157 in nuts, cocoa and spices has been well documented, while growers routinely treat their products with propylene oxide to reduce other bacteria, molds and yeast as well.
Industries use methyl bromide to control stored products insects.
This study is underway at the Dried Fruit Association of California. Propylene oxide is particularly effective on eggs. A study on the rate of kill on the Codling Moth larvae in walnuts, as well as, off gassing studies on raisins, prunes and figs are scheduled. The allowable residue tolerance for propylene oxide is 300 ppm. However, these residues are not persistent as they will evaporate rapidly from the substrate due to the relatively high vapor pressure of propylene oxide.