Abstract: To optimize the conditions for chilli sauce sterilization by means of microwave treatment, Box-Benhnken experimental design was utilized to develop a quadratic polynomial model describing order-of-magnitude reduction in total viable count as a function of three key sterilization conditions, namely microwave power, temperature and treatment time, with verified validity, and response surfaces and contours were plotted to analyze the effects of pairwise interactions among the three conditions on their function. The order of importance of the three factors affecting the sterilization of chilli sauce from high to low was microwave power, temperature and treatment time. Microwave treatment with a 960 W power for 8.9 min was the optimized sterilization condition. Under this condition, the developed regression predicted a 3.75-order-of-magnitude reduction in total viable count, in good agreement with the observed value. Thus, the model is reliable. 

Key words: chilli sauce, microwave sterilization, response surface methodology, optimization