Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2002
Publication Date: 11/6/2002
Citation: FAN, X., TOIVONEN, P.M., RAJKOWSKI, K.T., BAXENDALE, K.J. WARM WATER TREATMENT IN COMBINATION WITH MODIFIED ATMOSPHERE PACKAGING REDUCED UNDESIRABLE EFFECTS OF IRRADIATION ON THE QUALITY OF FRESH-CUT ICEBERG LETTUCE.. JOURNAL OF FOOD SCIENCE. 2002. V. 51. P. 1231-1236. Interpretive Summary: Ionizing irradiation can effectively inactivate foodborne pathogens in many fresh fruits and vegetables. However, irradiation at high doses may induce undesirable quality changes. Therefore, irradiation will likely have to be used in combination with other treatments to achieve a 5-log reduction of foodborne pathogens on fresh and processed fruits and vegetables. The impact of the combinative treatments on quality of fresh-cut vegetables is a concern. This study was conducted to investigate the effect of warm water dipping in combination with irradiation on the quality of fresh-cut lettuce. Fresh-cut iceberg lettuce, immersed into 5 C or 47 C water for 2 min and packaged in breathable film bags, was irradiated at 0, 0.5, 1 and 2 kGy. The treatment of lettuce in warm water before irradiation to 0.5 and 1.0 kGy had the least browning and best overall visual quality without consistent losses in firmness, vitamin C, or antioxidant. Overall, our results suggest that warm water treatment in combination with low dose (0.5 and 1 kGy) radiation can be used to ensure quality while effectively sanitizing fresh-cut lettuce. Our study provides a novel approach for the fresh-cut industry to improve safety and quality of lettuce.
Technical Abstract: Fresh-cut iceberg lettuce, immersed into 5 C or 47 C water for 2 min and packaged in breathable film bags, was irradiated at 0, 0.5, 1 and 2 kGy. The lettuce was then stored at 3 C for 21 days. Dipping lettuce to 47 °C water for 2 min prior to irradiation reduced antioxidant and phenolic accumulations induced by irradiation. Irradiation at 2 kGy increased electrolyte leakage and sogginess of lettuce dipped in both temperatures. Overall, lettuce treated with warm water and irradiated at 0.5 and 1.0 kGy had the least browning and best overall visual quality without consistent loss in texture, vitamin C or total antioxidants after 14 and 21 d storage at 3 °C. Overall, our results suggest that low dose (0.5 and 1 kGy) irradiation in combination with warm water treatment can be used to ensure quality while effectively sanitizing fresh-cut lettuce.