Optimization of plasma-processed air (PPA) inactivation of Escherichia coli in button mushrooms for extending the shelf life by response surface methodology

The effect of plasma-processed air (PPA) treatment with different conditions (time, power and flow rate) on the inactivation of Escherichia coli (E. coli) in button mushroom was evaluated. Response surface methodology (RSM) was applied to optimize PPA treatments on the E. coli of button mushrooms. According to the response surface analysis, the optimal treatment parameters were a treatment time of 12 min, treatment power of 90W and flow rate of 1.2 l min⁻¹. As with verifying tests from the optimization exercise, the number of E. coli reduced by 5.27 log CFU/g at the determined optimum conditions. The scanning electronic microscopy (SEM) micrography showed that the surface of the E. coli was significantly changed under the optimized PPA treatment. Quality parameters of button mushrooms treated at the determined optimum conditions were compared with untreated samples during the storage for 12 d at 4 °C±1 °C. The PPA treatment was found to be effective in inhibiting microbes and preserving postharvest quality in button mushrooms, and these results suggested PPA treatment may provide an alternative for the sterilization of foodborne and maintaining postharvest of fruits and vegetables.