O BULLETIN 15, U. S. DEPARTMENT OF AGRICULTURE. 
SUMMARY. 
The foregoing observations and experiments have brought out 
several points : 
(1) Cereals may become infested before they are packed, after the 
packages are placed in warehouses, and in the grocery stores. 
(2) Insects find their way in at the small holes which are usually 
present at the corners of unsealed packages or at holes accidentally 
punched in the sides. 
(3) Thorough sterilization 1 at 180° F. kills all insect life; and if 
the cereal is run from the sterilizer either through a sterile cooler or 
directly into sterile packages and immediately sealed, it will not 
become infested unless the package is broken. 
(4) Sterilization of the knocked-down cartons before packing and 
cleanliness with regard to the exclusion of insects from the packing 
room will greatly facilitate the preparation of sterile packages and 
is strongly recommended. 
(5) It is absolutely necessary that all machinery connecting the 
sterilizer and the packages be free from insects. If the cereal is 
passed through chutes or conveyors which can not be sterilized or 
are not kept sterile, it will, through these sources, become infested 
even though the cereal was previously sterile and was packed in 
sterile packages. 
i The writer has not extensively investigated sterilizers, but the following description, furnished through 
the kindness of Mr. Bert D. Ingles, of a sterilizer used by a large flour mill in California may be of interest 
here. "In this sterilizer the screw conveyor is 6 inches in diameter and handles approximately 500 pounds 
of cereal per hour. The steam is held at 160 pounds pressure, which is equal to 370.5° F. A machine 8 feet 
long will heat the cereal under these conditions to 180° F. in two minutes without any difficulty. Such a 
sterilization does not injure the cereal." 
ADDITIONAL COPIES of this publication 
il may be procured from the Superintend- 
ent of Documents, Government Printing 
Office, Washington, D. C. , at 5 cents per copy 
