Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/12/2010
Publication Date: 6/1/2010
Citation: Inatsu, Y., Kitagawa, T., Bari, M.L., Nei, D., Juneja, V.K., Kawamoto, S. 2010. Effectiveness of acidified sodium chlorite and other sanitizers to control Escherichia coli O157:H7 on tomato surfaces. Foodborne Pathogens and Disease. 7(6)629-635. Interpretive Summary: The presence of pathogenic bacteria on the surface of tomatoes sold in the market place has been well-documented. We assessed the efficacy of different sanitizers to inactivate a pathogenic bacterium, Escherichia coli O157:H7, on tomatoes. Acidified sodium chlorite was found to be the most effective sanitizer in decontaminating the surface of tomatoes. Use of this sanitizer did not have a negative impact on the color, appearance, texture, and taste of the treated tomatoes. Our findings will help the retail food service establishments to rely on the effectiveness of acidified sodium chlorite in decontaminating the surface of tomatoes.
Technical Abstract: The use of a suitable sanitizer can reduce the risk of produce related food-borne illnesses. We evaluated the effectiveness of several sanitizers to reduce inoculated Escherichia coli O157:H7 on petit tomatoes. Depending on the method of inoculation (dipping / spotting), each of 80g of inoculated tomatoes was washed in 400 mL of sanitizer solutions or water for 5 minutes. The effectiveness of sanitizers on spot inoculated tomatoes was higher (2.0 log CFU/g) than those of dip inoculated samples. Washing with water or chlorinated water caused a reduction of 1.3 log CFU/g of E. coli O157:H7 in dip inoculated (6.7 log CFU/g) tomatoes. Washing with 1 g/L of lactic acid, phytic acid, calcinated seashells (oyster / sakhalin surf clam) and chitosan (in 0.5g/L of lactic acid) did not exhibit a higher effectiveness than that of water wash alone (1.0 log CFU/g). Acidified sodium chlorite (ASC) solution prepared from 0.5 g/L of sodium chlorite and 1.0 g/L lactic or phytic acid resulted in a reduction of 3.5 log CFU/g of surface attached E. coli. Water or lactic acid (0.5g/L) wash followed by a second wash with ASC (0.5 g/L of sodium chlorite and 5 g/L of lactic acid) did not exhibit an additional sanitary effectiveness compared to a single wash with ASC. However, washing with ASC followed by a second wash with 1g/L chitosan (in 0.5g/L lactic acid) exhibited an additional 1.0 log CFU/g reduction for up to 2 days of storage at 10C compared to a secondary wash with water. No significant difference in color, appearance, texture, and taste was observed among the washed samples of petit tomatoes.