|Dowdy, Alan - USDA-APHIS-PPQ|
|Subramanyam, Bhadriraju - KANSAS STATE UNIV|
Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 2, 2004
Publication Date: January 1, 2005
Citation: Akdogan, H.P., Casada, M., Dowdy, A., Subramanyam, B. 2005. A novel method for analyzing grain facility heat treatment data. Journal of Stored Products Research. 2005. V 41: 175-185. Interpretive Summary: This research investigated the use and effectiveness of high temperature for control of stored-product insects in a grain processing facility. Two different heating methods were compared. One method of heating used gas heaters that were placed outside the building. Hot air was channeled inside the building with ducts. The other method used portable electric heaters placed within the building. For both methods, it was important to keep the heat throughout the building as well-mixed as possible, with treatment temperature in the 50o to 60oC range to kill stored-product insects. A simple mathematical equation was used to describe the percent floor surface area of the facility that was under 50oC as a function of treatment duration. The same equation was successfully used to correlate maximum floor temperature to percent floor surface area. Maps of maximum floor temperatures of the floor surface were created. These computer-generated maps were useful for determining under- and over-heated areas of the heat-treated facility. Under-heated areas carry high risk of insect survival and over-heated areas pose risk of damaging heat-sensitive equipment. The electric heating in this study resulted in more under-heated areas than gas heating system, while the gas heating was slower to reach to the target temperature of 50oC.
Technical Abstract: Use of elevated temperatures (greater than 50oC) in food processing facilities for management of stored-product insects is a viable alternative for fumigation with methyl bromide. Effectiveness of heat treatment in controlling insects is determined by how uniformly temperatures between 50o to 60oC are attained in areas subjected to the treatment. The pilot flour mill at Kansas State University, Manhattan, KS, was heated with gas (positive pressure) and electric (neutral pressure) heaters in June and August 1999, respectively. The effectiveness of heat distribution, using the two different heating systems, was compared using a unique surface area method. A two parameter nonlinear log-logistic equation was used to predict percent of floor surface area that is under 50oC as a function of maximum floor temperature and treatment time. With electric heating, time delays for temperature increase were considerably shorter than with gas heating. However, electric heating resulted in substantial amounts of under-heated floor areas (T<50oC) throughout the facility at the end of the heat treatment. The methods provided here can be used to design and evaluate heat treatment strategy in grain and food processing facilities.