Combined Effect of Nisin and Ohmic Heating on Bacillus cereus Inactivation and Quality Preservation in Apple Juice

There is increasing demand for minimally processed, risk‐free fruit juices necessitating novel treatments to control foodborne pathogens while preserving physicochemical and sensory attributes. This study investigates the synergistic efficacy of Lactococcus lactis‐derived bacteriocin (nisin) and ohmic heating (OH) treatment against Bacillus cereus, a Gram‐positive foodborne pathogen capable of forming heat‐resistant spores and producing toxins during vegetative growth. The antimicrobial effectiveness was evaluated using nisin concentrations (0.1 and 0.2 mg/mL) and OH treatments applied as high voltage‐short time (HVST) and low voltage‐long time (LVLT) combinations in apple juice as a model acidic beverage matrix. The combination of 0.2 mg/mL nisin with HVST (60 V for 90 s) achieved complete pathogen inactivation, surpassing heat‐alone treatment (90 s: 4.1 log CFU/mL reduction, p < 0.05). Synergistic treatments reduced B. cereus viability by 88.6%–93.9%, with scanning electron microscopy (SEM) revealing significant cell membrane damage (p < 0.05). The mild temperature achieved during OH likely contributed to maintaining juice quality attributes, including pH, glucose and dissolved oxygen levels, which showed no statistically significant changes compared with the untreated control (p > 0.05). Statistical analysis using ANOVA confirmed treatment significance (p < 0.05) based on log reductions (3.2–4.1 log CFU/mL) under optimised conditions (0.2 mg/mL nisin + 60 V/30s), demonstrating superior efficacy over heat‐alone methods. These findings demonstrate the potential applicability of combining nisin and OH as a hurdle strategy to enhance microbial control in acidic beverage systems while maintaining product quality.