A methodology was developed for determining destruction of bacterial spores during extrusion cooking in a single screw extruder. Procedures were developed for estimating processing time at different screw speeds and calculation of “D-” and “z-values.” The proposed methodology evaluated destruction of Bacillus globigii spores in 18% moisture corn/ soybean mixture (70/30%, w/w). “D-value” expressed on the basis of average time at mass temperature >95°C during extrusion was the most conservative estimate of spore sensitivity. Times ranged from 1.7 sec at 115°C to 6.6 sec at 100°C maximum mass temperatures. These “D-values” resulted in a “z-value” of 25.3°C., similar to that reported for the same strain with dry heat.