Abstract:Brain heart infusion (BHI) broth as nutrient components and two cold water soluble gel, xanthan gum and carrageenan as complex gel were used to develop a gel bacterial testing plate for the detection of aerobic bacterial count in food. The optimal combination of the key additional components was determined by orthogonal test, and the effects of the ratio of the two gels on physical and chemical and microbiological results were examined. The optimal results were obtained when the components of medium were BHI 38.5 g/L, TTC 0.008 g/L, SAP 0.05 g/L, sodium pyruvate 1.5 g/L, and the proportion of complex gel was xanthan gum: carrageenan=8:2. Compared with national standard method, the gel testing plate method of this study had a good correlation (R2>0.99), achieving the same limit (2 CFU/mL) detection and sensitivity (100%); Compared with 3M Petrifilm, the quantitative results showed no significant difference, the two methods linear relationship was good (R2=0.99). The detection limit, sensitivity, and accuracy of the colony count testing plate in this study were no significant differences in comparison with the national method, it can be applied to the detection of colony count in food.
