Most commercially available disinfectants cause serious health side effects. This study investigates controlled carbonation of ${\mathit{Ca}(\mathit{OH})}_2$by mixing with dry ice and the use of the resultant particles as a more health friendly antimicrobial agent. In one mixing scheme, alternate layering of $\mathit{Ca}{(\mathit{OH})}_2$ and dry ice is used with no additional mixing, while in another a Hamilton Beach mixer is utilized. X – ray diffraction confirmed the identity of the resultant particles and thermogravimetry measured their bulk composition. Fourier transform infrared spectroscopy displayed different surface composition than ${\mathit{Ca}(\mathit{OH})}_2$suggesting a core – shell structured product. Commercial ${\mathit{Ca}(\mathit{OH})}_2-{\mathit{CaCO}}_3$ core – shell (CSCC) particles prepared under quiescent conditions and the particles prepared in this work displayed different extent of aggregated structures, despite the different mixing strategies. Thicker $\mathit{Ca}{\mathit{CO}}_3$ shell and CSCC particle aggregation corresponded to higher content of $\mathit{Ca}{\mathit{CO}}_3$ as estimated by acid/base titration. The antibacterial activity of the CSCC particles was evaluated using a novel strategy where cells are mixed with a fixed density of particles as a slurry. Both gram – negative; namely P.aeruginosa and E.coli, and gram – positive; namely S.aureus, bacteria were tested. The results confirmed the superior antibacterial properties of the in – house prepared CSCC particles, where at least 2 times more effective particles than ${\mathit{Ca}(\mathit{OH})}_2$ and commercial particles were reported against gram-positive bacteria. The antibacterial properties of the particles were correlated to their morphology.