A low defectivity colloidal silica-based product slurry for use in chemical mechanical planarization (CMP) and an associated production method are described. The product slurry is produced using centrifugation of and optionally with addition of a surfactant to a starting colloidal silica (which can be a commercially available colloidal silica). The product slurry has substantially lower levels of soluble polymeric silicates than does the starting colloidal silica and affords lower defectivity levels when used in a slurry for CMP processing than does the starting colloidal silica.