142 MISC. PUBLICATION 5 4 0, U. S. DEPT. OF AGRICULTURE 



kerosene alone or combined with oil extracts of pyrethrum or lethant 

 is excellent also. These sprays may be applied by hand or power 

 sprayers for small areas, or by regular orchard power sprayers for 

 large and extensive structures. They should be applied to the 

 ceilings, walls, floors, under the floors, and, in fact, everywhere insects 

 or mites are likely to find hiding places. 



The addition of 1 percent of creosote will kill the wood-boring 

 cadelle and the lesser grain beetle in wooden containers. While 

 there is no great fire hazard with the careful use of these sprays, 

 proper precautions should be taken to prevent fires and to secure the 

 sanction of insurance companies and underwriters involved. 



Temperature and Moisture 



Proper temperature and moisture control of storage facilities may 

 effectively prevent infestation or retard the activities of insect pests 

 indefinitely. Lack of such control may favor the insects and mites 

 by providing ideal conditions for their development, feeding, and 

 breeding in the foodstuffs. 



Even and mild to warm temperatures combined with a high 

 moisture content in the product (10 percent and above) will favor 

 pest development by making the food more attractive to pests and 

 the living conditions ideal. Thus, in the milder temperate regions 

 and in the tropics, it is difficult to store dried fruits and vegetables 

 because of the destructive work of mites, insects, fungi, and bacteria. 

 Regions of great extremes of temperature offer a certain amount of 

 protection to stored foods. Low temperatures and ordinary cold 

 storage of 40° to 50° F. will prevent insect development in ware- 

 houses. Temperatures of 30° will kill all stages of the insect de- 

 velopment if maintained constant throughout the bulk of the 

 material. 



High temperatures of 120° to 130° F. will prove effective in killing 

 all forms of mite and insect life. The heat may be supplied by 

 steam pipes and has proved effective where practical. Fans are 

 invaluable in sterilization work. 



The effectiveness of temperature is determined by the extent to 

 which it is made to operate throughout the sacks, bins, or entire 

 storage facilities. Unless the materials in storage are arranged so 

 that temperature can penetrate evenly and effectively throughout the 

 bins and sacks, it is necessary to provide proper ventilation or to 

 bring the material into direct contact with the temperature. This 

 will add considerably to the handling and shifting of the produce 

 unless the material is stored in bulk in relatively small bins or units. 



THE CONTROL LABORATORY 



Every food-dehydration plant, large or small, must have a control 

 laboratory. This laboratory may consist of minimum essentials, such 

 as equipment and personnel for moisture testing, testing for adequate 

 blanching, and testing of quality in raw and finished products, or it 

 may be much more elaborate, even sufficient for research work. 



Regardless of size, it is an important feature in any plant, and it 

 should be regarded as a unit worthy of separate consideration and 

 not as an incidental matter. The man or woman in charge should 

 have chemical training and plant experience and should be free to 



