49F-14 |
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T. L. SELBY1, E. Wong2, Y. Han1, D. E. Gerrard1, and R. H. Linton1. (1) Dept. of Food Science, Purdue University, 745 Agriculture Mall Drive, West Lafayette, IN 47907, (2) Escuela de Tecnología de Alimentos, University de Costa Rica, San Pedro de Montes de Oca, San Josè, Costa Rica Concerns about minimally processed fruits and vegetables have been raised due to outbreaks caused by bacterial pathogens. Development of highly effective sanitation techniques is needed to reduce pathogens on fruits and vegetables. Our objectives were to: (a) determine the efficacy of chlorine dioxide (ClO2) gas at reducing levels of Salmonella and E. coli O157:H7 on mushrooms and (b) evaluate physical and chemical quality characteristics. Mushrooms were spot-inoculated on the top and the underneath side of the cap with 7-8 log cfu/g Salmonella or E. coli O157:H7, dried for 2 hrs, and treated with 6-1000 ppm ClO2 gas for 3-17 min, at 22ºC and RH between 90-96%, using a continuous laboratory treatment system. Bacterial populations were enumerated using a membrane-transferring plating method using tryptic soy agar and xylose lysine desoxycholate or macconkey sorbitol agar. For quality, mushrooms were treated with 800 ppm ClO2 gas for 13.5 min and examined for color (Hunter), residual ClO2, chlorite, free Cl2, and chloramines. After 100 ppm ClO2 gas treatment for 15 min, the log reductions were 2.69 and 1.30 log cfu/g Salmonella and 4.22 and 4.08 log cfu/g E. coli O157:H7. After 1000 ppm ClO2 gas treatment for 15 min, both the top and the underside of the cap exhibited reductions of 4.53 and 4.45 log cfu/g Salmonella and 4.52 and 4.38 log cfu/g E. coli O157:H7. Additionally, efficacy of ClO2 gas increased with increasing concentrations and treatment times. No significant (P>0.05) difference in color was detected after treatment for L and b Hunter color values, however, a Hunter value differed (P<0.05). Residues ClO2, free available chlorine, chloramines, and chlorite on treated mushrooms were 0.000 mg/g, 0.000 mg/g, 0.000 mg/g, and 0.004 mg/g, respectively. Gaseous ClO2 is a potential and promising tool which enhances the safety of produce while extending shelf-life and maintaining quality.
Session 49F, Fruit & Vegetable Products: Fresh vegetables
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