45G-15 |
Pathogen reduction on lettuce and radishes using hydrogen peroxide |
D. L. HENTGES, School of Family and Consumer Sciences, Bowling Green State University, 206 Johnston Hall, Bowling Green, OH 43403 A proposed habitat for long duration space missions is the Bioregenerative Planetary Life Support Systems Test Complex (BIO-Plex). The primary methods for controlling microorganisms on lettuce and radishes, crops for the BIO-Plex, are sanitation and refrigerated storage. To determine the concentration and duration of exposure to hydrogen peroxide (H2O2) needed to reduce pathogens on lettuce and radishes without causing quality defects. Lettuce leaves and radishes were dipped in 1% H2O2, 2% H2O2, 100 ppm chlorine, or water for 0.5, 2, 5, and 10 minutes. The controls received no treatment. Samples were stored in sterile plastic bags at 5„aC for 0, 3, 7, and 14 days. Total aerobic microorganisms, Escherichia coli, and coliform populations were enumerated. Fourteen panelists evaluated each product on a 1-5 point scale for overall appearance, color, smell, and texture. Lettuce leaves and radishes immersed in H2O2 and stored at 5„aC for 0-3 days had lower counts of aerobic, E.coli, and total coliform microorganisms. Lettuce and radishes had higher counts when stored for 7-14 days. There were no apparent trends of treatment or exposure time related to quality ratings of lettuce; however, lettuce stored for 7-14 days received lower quality ratings for overall appearance and texture. Sanitation treatments had a greater effect on sensory characteristics of radishes than lettuce. Radishes treated with H2O2 had uneven bleaching, a mild odor, and lower ratings for overall appearance. There were no significant differences for texture of radishes with any of the treatments, exposure times, and storage times. 1% H2O2 may be sufficient for reducing pathogens on lettuce and radishes without causing excessive quality defects during short term storage. H2O2 is a possible chemical sanitizer for use in the BIO-Plex since it is an effective disinfectant, can be regenerated, and will not destroy resident bacteria in the water recovery system.
Session 45G, Fruit & Vegetable Products: Vegetables (Fresh)
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