Effect of food additives on heat sensitivity of Listeria monocytogenes H-12 and decontamination of Kitchen Utensils

摘要

Effect of food additives on the heat sensitivity of Listeria monocytogenes H-12 inoculated into Pollack surimi was investigated and also confirmed the effectiveness of various decontamination method such as tap water washing, chlorination, ultraviolet irradiation and heat treatment having been applied on cooking utensils. Food additives such as polyphosphate, chitosan, and potassium sorbate increased heat sensitivity of L. monocytogenes H-12 and polyphosphate showed the strongest synergistic effect. The tested strain was not detected from stainless steel and plastic cutting board contaminated with 10~4 approx 10~5/cm~2 of L. monocytogenes H-12 after tap water washing for 10 seconds or 1 minute, but washing effect was not found in wooden cutting board. The chlorination of stainless steel and plastic cutting board for 10 seconds with 5 approx 50 ppm solution eliminated all cells of the contaminated strain, however any change of the viable cell count was not observed in the chlorination of wooden cutting board. UV irradiation on stainless steel and plastic cutting board for 5 minutes with 15 W above 30 cm eliminated the contaminated strain, but the tested strain was still found after 60 seconds of irradiation on wooden cutting board. The treatment of hot water on all used cutting boards for 10 seconds at 70 deg C resulted in complete loss of viability of the contaminated strain.