Data on Quantification of Bacillus cereus sensu lato biofilms by Microtiter Plate Biofilm Formation Assay
The microtiter plate (MTP) biofilm formation assay is a method for the study of early biofilm formation on abiotic surfaces. It is a colorimetric technique that uses crystal violet dye to stain attached biofilms and quantify by using an absorbance microtiter plate reader. In this data, we evaluated the ability of B. cereus sensu lato isolates from soil and milk powder samples for their production of biofilms after a total of 48 hr incubation period in the 96-well microtiter plate. The biofilm production was induced by initially exposing them in nutrient depleted medium at its first 24 hr and then replacing freshly prepared double strength broth for the next incubation period at 30°C. The optical densities of the bacterial growth in the wells were read at 630 nm while the stained biofilms that solubilized in absolute ethanol were read 570 nm. The biofilm measurements were calculated and the degree of biofilm production of each isolate was classified according to biofilm formation categories adapted from previous researchers. Therefore, the assay concluded the negative impact of B. cereus group by forming biofilms on abiotic surfaces, such as food contact surfaces in food production industries.