Combined treatments of chestnut shell extract, fumaric acid, and mild heat to inactivate foodborne pathogens inoculated on beetroot (Beta vulgaris L.) leaves.

To evaluate the combined treatments of chestnut shell extract (CSE), fumaric acid (FA), and mild heat (MH) on the inactivation of Escherichia coli O157:H7 and Listeria monocytogenes inoculated on beetroot leaves, samples were treated with different concentrations of CSE or FA, as well as combinations of 0.5% CSE/0.5% FA and 0.5% CSE/MH at 50°C/0.5% FA. Among the treatments, the combined treatment of CSE/MH/FA was most effective, reducing the populations of E. coli O157:H7 and L. monocytogenes on beetroot leaves by 3.18 and 3.76 log CFU/g, respectively. In addition, the initial populations of pre-existing bacteria on beetroot leaves were reduced by 2.58 log CFU/g after the combined treatment. The inactivation effect was retained during storage at 4°C for 8 days. These results indicate that the combined treatment of CSE, FA, and MH can be effective in decontamination from foodborne pathogens and improving in the microbial safety of beetroot leaves during storage.