The objectives of this study were to: investigate the microflotation of Bacillus cereus, which is larger and more hydrophobic than the other bacteria studied; determine the effect of coagulant concentration on the pH range of efficient microflotation; and, examine the relative effectiveness of soluble and insoluble cationic and anionic collectors. The foam separation of Bacillus cereus was investigated using the microflotation technique. The removal of the organisms was examined as a function of pH at several coagulant doses, and different types of collectors were used. These two factors determined the pH range that achieved good removals. In general, aggregation of the organisms improved the removals. Removals were most efficient when using CTAB, a strongly ionized cationic surfactant. Although NaLS was the least effective of the collectors, these studies with CTAB and NaLS indicate that soluble surfactants may be used with the microflotation technique. The results of this study suggest that bacteria are slowly coagulated at low pH by hydrogen ion or soluble aluminum species.