MICROBIAL HEAT-PRODUCTION IN STORED WHEAT

Equations were developed to calculate microbial heat production from c arbon dioxide (CO2) production data in stored wheat at 10-40 degrees C and 15.5-24.5% moisture content, assuming that CO2 production was due to aerobic and anaerobic respiration. Aerobic respiration accounted f or 91 to 97% of total heat production. At 10 degrees C, heat productio n rates were generally low and constant, whereas at 20 degrees C, heat production rates increased with storage time at all test moisture con tents except at 23.8%. At 30 degrees C, heat production rates at 18.6- 20.8% moisture content peaked after 9 d and then decreased to lower co nstant rates. The highest rate of heat production, 36.2 mW/kg, occurre d at 30 degrees C at 19.8% moisture content. At 40 degrees C, signific ant heat production occurred at the lower moisture content of 15.5%, b ut at higher moisture contents of 19.8 and 24.1%, heat production rate s decreased sharply as storage time increased. The combined effects of temperature and moisture content on heat production rates wen modelle d by multiple linear regression.