36E-24

H. J. KIM¹, H. Feng¹, S. A. Toshkov¹, and X. Fan². (1) Dept. of Food Science & Human Nutrition, Univ. of Illinois, Urbana-Champaign, 1304 W. Pennsylvania Ave., 382-Q Agricultural Engineering Science Bldg., MC-642, Urbana, IL 61801, (2) Food Safety Intervention Technologies Research Unit, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598

Fresh-cut produce can be easily contaminated by spoilage microorganisms and foodborne pathogens. Recent foodborne illness outbreaks associated with fresh-cut green onions have raised concerns about the safety of this product. Immersion of produce in warm water has been used to control surface microorganisms. Irradiation has also been used as a powerful microbial control method in selected foods. The combination of warm water dip with irradiation might provide an effective means for green onion microbial safety control.The objective of this study was to examine the efficacy of a sequential treatment of fresh-cut green onions with warm water dip followed by ionizing irradiation for microbial reduction and product quality maintenance. Fresh-cut green onions were treated with and without warm water (50^oC for 20 sec) and packaged prior to irradiation at 0, 0.5, 1.0, and 1.5 kGy, then stored at 4^oC for 14 d. Color, texture, decay, electrolyte leakage (EL), sensory qualities, and total aerobic count (TAC) were recorded at 1, 4, 8, and 14 d. of storage. The warm water treatment reduced the TAC by 0.9 log initially but the beneficial effect disappeared during storage. Irradiation effectively reduced TAC and maintained a low microbial growth during the 14-day storage. Irradiated samples exhibited a similar decay development and EL in the first 8 d. of storage compared with the control. Toward the end of the 14-d. storage, irradiated samples maintained a relatively low decay percentage and EL. Sensory evaluation recorded significantly higher scores of overall visual quality and greenness, and lower off-odor scores for irradiated samples regardless of warm water dip. With the test conditions used in this study, the warm water treatment did not provide added benefits for quality improvement. Irradiation at all tested doses reduced TAC and the development of decay and off-odor, improved visual quality, and preserved green color.

Session 36E, Fruit & Vegetable Products: General
8:30 AM - 12:00 PM, Monday AM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana