Reduction of Listeria monocytogenes on Various Food Contact Surfaces by Listeria Phage Suspension or Electrolyzed Oxidizing Water

Listeria monocytogenes often contaminates food processing areas, including food contact surfaces (FCS), thus leading to occurrence of re- and cross-contamination of finished products. Effective sanitizing agents are needed to reduce Listens contamination. The phage suspension (broad host-range phage, LP-124) and electrolyzed oxidizing water (EOW, pH 2.5 and oxidation-reduction potential, ORP 1080 mV) were evaluated against L. monocytogenes on three food contact surfaces (polyethylene - PE cutting board (n = 3), stainless steel SS spoon (n = 3) and SS sieve (n = 3), and cotton towel (n = 3) directly used on ready-to-eat squid sushi). The initial L. monocytogenes concentration of 4.3 to 5.0 log(10)CFU/100 cm(2) was reduced by 1.2 to 2.4 log units and 2.7 to 3.7 log units after treatments with the phage suspension and EOW, respectively. Counts below the detection limit (< 2 log(10)CFU/100 cm(2)) were observed on all surfaces treated with EOW for 5 min contact time, suggesting a high efficacy of EOW against L. monocytogenes. The highest CFU reduction was on SS spoon (2.4 log units) treated with Listens phage and on PE cutting board (3.7 log units) treated with EOW. Both treatments are of interest for applications to inactivate L. monocytogenes on different surfaces in the food processing facilities as well as retail operations.