MONITORING MICROBIAL COLONY GROWTH USING IMAGE-ANALYSIS TECHNIQUES

Colonies of Bacillus cereus were grown on the surface of nutrient agar plates. After inoculation as spread plates from serial dilutions, dia meter and coefficients of circularity were determined from captured im ages using a particle analysis program. Radial growth rate was strictl y linear whilst the coefficient of circularity fell with time. Followi ng point inoculation at the centre of the plate, colony growth was mon itored daily and images captured, converted to absorbance and presente d as wire frame diagrams. Successive subtraction of these images indic ated that growth took place after about 24 hours, only at the peripher y of the colony.