Synergistic effects of high pressure processing and slightly acidic electrolysed water on the inactivation of Bacillus cereus spores

Bacillus spores are concerns for their resistance to heat, high pressure processing (HPP), and disinfectants. We examined the effects of HPP and slightly acidic electrolysed water (SAEW) on inactivation of B. cereus spores. Spores' suspensions were prepared with 2-(N-morpholino) ethanesulfonic acid (MES) buffer or SAEW with available chlorine content (ACC) of 24, 35, 44 or 55 mg L-1, and then subjected to HPP. The individual effects of HPP or SAEW on spores were negligible (<1.0 log CFU mL(-1)). With factorial design and ANOVA analysis, HPP + SAEW treatment was shown to have significantly positive effects on spores' inactivation. The optimal conditions were 300 MPa HPP + SAEW with 44 mg L-1 ACC or 200 MPa HPP + SAEW with 44 mg L-1 ACC + 500 MPa HPP, producing reductions of 3.27 and 3.99 log CFU mL(-1), respectively. HPP + SAEW have potentials to serve as two effective hurdle techniques for inactivating B. cereus spores.