Single and combined decontamination effects of power-ultrasound, peroxyacetic acid and sodium chloride sanitizing treatments on Escherichia coli, Bacillus cereus and Penicillium expansum inoculated dried figs

摘要

Microbial contaminations and related issues are causing serious economic losses to the global trade of dried figs. A significant amount of dried figs are rejected at the customs gates after legally required analyses, which in turn brings several problems covering the destruction of foods, environmental hazards, and food safety issues. In the present study, Escherichia coli, Bacillus cereus, and Penicillium expansum inoculated (10(7) CFU/g) dried figs (Ficus carica cv. Sarilop) were subjected to sanitation treatments using ultrasound application (US; 100-600 W), peroxyacetic acid (PAA; 40-200 mg/L) and sodium chloride (NaCl; 4-12%); separately and/or in combinations using a central composite design by response surface methodology. In case of combined (dual/triple) treatments, the optimum process conditions were [US: 527 W, PAA: 148 mg/L], [US: 527 W, NaCl: 11.0%], [PAA: 108 mg/L, NaCl: 10.6%], [US: 203 W, PAA: 89 mg/L, NaCl: 10.4%]. Microbial decontamination by combined US and PAA showed 3.35, 0.93, and 0.90 log CFU/g while the US, PAA, and NaCl combination showed 3.09, 0.82, and 0.98 log CFU/g for E. coli, B. cereus, and P. expansum, respectively. The triple combination was found better for microbial decontamination as it consumed less US power in addition to less comparative concentrations of PAA and NaCl.