Immediately after treatments, aliquots of 1 ml soup from each
sample were serially diluted (1:10) in 0.1% peptone water and vortexed.
Quantification of B. subtilis colonies (CFU/ml) was performed
with surface plating method using polymyxin pyruvate egg yolk
mannitol bromothymol blue agar (PEMBA) medium selective for Bacillus