Inactivation of <i>Bacillus cereus</i> Spores by Calcium Chloride Slightly Acidic Electrolyzed Water: Effects on Structural Integrity, Germination Inhibition, and Mechanistic Insights

ABSTRACT Spores present a concealed threat to food safety due to their remarkable resistance. Slightly acidic electrolyzed water (SAEW), known for its high efficiency, broad‐spectrum effectiveness, and safety, has been widely employed to eliminate bacteria and their spores. Calcium ions (Ca 2+ ) promote spore germination; therefore, this study innovatively explores the efficacy of slightly acidic electrolyzed water containing calcium chloride (SAEW‐CaCl 2 ) in eradicating B. cereus spores, with a particular focus on its unique ability to simultaneously disrupt spore structural integrity and induce germination. Although the bactericidal properties of SAEW are well established, the incorporation of Ca 2+ in this study represents a novel approach to enhancing its sporicidal activity. The results demonstrated that SAEW‐CaCl 2 exhibited a higher sporicidal efficacy compared to ordinary slightly acidic electrolyzed water (SAEW‐NaCl) at available chlorine concentrations (ACC) of 90 and 120 mg/L, treatment durations of 5–60 min (5, 10, 20, 30, and 60 min), and Ca 2+ concentrations of 30 and 40 mmol/L. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed severe destruction of the spore protective layers (coats and cortex) and core leakage. TEM images further indicated the emergence of vegetative cells, suggesting that SAEW‐CaCl 2 induced spore germination. Notably, treatment with SAEW‐CaCl 2 reduced spore heat resistance of spores by 42.6% after 20 min and increased the release of pyridine‐2,6‐dicarboxylic acid (DPA) to 52.45% at an ACC of 120 mg/L, significantly surpassing SAEW‐NaCl ( p &lt; 0.05). Growth curve analyses demonstrated that SAEW‐CaCl 2 effectively inhibited normal spore proliferation and reproduction. Therefore, SAEW‐CaCl 2 inactivated spores by either destroying their structures or inducing spore germination. These findings suggest that SAEW‐CaCl 2 is an effective agent for inactivating B. cereus spores, providing alternative treatment options in the food industry.