Effect of pomegranate (Punica granatum) pomace extract as a washing agent on the inactivation of Listeria monocytogenes inoculated on fresh produce

摘要

Pomegranate pomace extract (PPE) was used as a substitute to chlorinated water for washing of fresh produce. PPE contained punicalagins and ellagic acids, and it had a good inhibitory effect against Listeria monocytogenes based on the results of disc diffusion test and time-kill assay. Red chard, beet, chicon and red mustard leaves were treated with 7mgmL(-1) PPE as a washing solution to inactivate L.monocytogenes inoculated on fresh produce and compared with 0.05mgmL(-1) NaOCl treatment. After the treatment, L.monocytogenes population on the four leafy vegetables was reduced by 1.96-2.97logCFUg(-1) compared to that on nontreated samples. The reductions in L.monocytogenes after PPE treatment were higher than those observed after NaOCl treatment. Further, the PPE treatment did not affect the surface colour of all fresh produce applied in this study. Thus, PPE can be used as an effective antimicrobial washing agent of fresh produce.