The antibacterial properties of tea polyphenols make them suitable for drinking water disinfection, but it is necessary to clarify the influence of metal ions on the sterilization efficacy. Epigallocatechin gallate (EGCG) was selected as a representative tea polyphenol, and the effects of calcium ion (Ca²⁺) concentration on its disinfection properties in Escherichia coli cultures were investigated. Changes in bacterial growth and structures were detected. The presence of low concentration Ca²⁺ (1–5 mM) inhibited the disinfection effect of EGCG but higher concentrations (6–10 mM) enhanced its effects. As Ca²⁺ concentration increased, the proportion of damaged bacteria also increased (15–43%). The presence of Ca²⁺ lessened the damaging effects of EGCG on the surface structures of E. coli but may have facilitated the entry of EGCG into the bacteria, enhancing its antibacterial efficacy. Tea polyphenols may be useful additives for the disinfection of groundwater and other raw waters containing calcium ions.

茶多酚的抗菌特性使其适用于饮用水消毒，但需要明确金属离子对杀菌效果的影响。选择表没食子儿茶素没食子酸酯 (EGCG) 作为代表性茶多酚，研究了钙离子 (Ca ²⁺ ) 浓度对其在大肠杆菌培养物中消毒性能的影响。检测到细菌生长和结构的变化。低浓度 Ca ²⁺ (1–5 mM) 的存在会抑制 EGCG 的消毒效果，但较高浓度 (6–10 mM) 会增强其效果。随着Ca ²⁺浓度的增加，受损细菌的比例也增加（15-43%）。Ca ²⁺的存在减轻了 EGCG 对大肠杆菌表面结构的破坏作用，但可能促进了 EGCG 进入细菌，增强了其抗菌功效。茶多酚可能是对地下水和其他含有钙离子的原水进行消毒的有用添加剂。