Cross-Contamination With Escherichia Coli, Listeria Monocytogenes, and Murine Norovirus During Potato Washing and Their Inactivation Using Peroxyacetic Acid and Aqueous Chlorine Dioxide.

This study evaluated the effectiveness of washing potatoes inoculated with Escherichia coli, Listeria monocytogenes, and murine norovirus (MNV) through agitation with peroxyacetic acid (PAA) and chlorine dioxide. Potential cross-contamination during simultaneous washing of inoculated and uninoculated potatoes and the effect of water reuse were also assessed. E. coli showed a reduction of 1.86-2.51 log colony-forming units (CFU)/potato when treated with 40 ppm PAA and 1.98-2.97 log CFU/potato when treated with 80 ppm chlorine dioxide (ClO2), both for 1-5 min. L. monocytogenes showed a reduction of 2.59 log CFU/potato when treated with 120 ppm PAA for 1 min and 2.55 log CFU/potato when treated with 80 ppm ClO2 for 5 min. MNV showed a reduction of 2.28 log CFU/potato when treated with ≥40 ppm PAA for 5 min; however, no significant reduction was noted on treatment with ClO2. During tap water washing, cross-contamination with E. coli and L. monocytogenes occurred at 3.01 and 3.22 log CFU/potato, respectively; however, MNV was not detected because of its higher LOD. PAA completely inhibited E. coli transfer (below the LOD), whereas ClO2 allowed limited transfer (0.83-1.30 log CFU/potato). However, L. monocytogenes transfer persisted in both treatments (2.74-3.46 log CFU/potato), showing only partial mitigation compared to tap water washing. Reuse of wash water significantly increased cross-contamination with E. coli and L. monocytogenes (p < 0.05); however, MNV transfer was not observed under any condition. For eradicating other types of microorganisms, the concentration must be determined according to the characteristics of each microorganism. PRACTICAL APPLICATIONS: This study revealed that washing potatoes with disinfectants like PAA or ClO2 can reduce harmful bacteria and viruses. PAA was effective even at concentrations below the regulatory limits. Hence, it may help prevent cross-contamination during bulk washing processes in food production facilities and kitchen environments.