Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2002
Publication Date: 6/21/2002
Citation: FAN, X., BAXENDALE, K.J. SENSORIAL AND CHEMICAL QUALITY OF GAMMA IRRADIATED FRESH-CUT ICEBERG LETTUCE IN MODIFIED ATMOSPHERE PACKAGES. JOURNAL OF FOOD PROTECTION. 2002. V. 65(11). P. 1760-1765. Interpretive Summary: Ionizing irradiation is non-thermal technology that effectively eliminates food-borne pathogens in various foods, including salad vegetables. High doses (above 1 kGy) of radiation may be required for the inactivation of some food-borne pathogens. However, the high doses of radiation may have adverse effects on sensorial and nutritional quality attributes, and it is unclear how high irradiation doses can be applied on many fresh-cut vegetables without deteriorated quality. This study was conducted to investigate the upper dose limit of gamma radiation on quality of fresh-cut iceberg lettuce packaged in modified atmospheres. Our results suggest that irradiation at 1 and 2 kGy improved visual quality of lettuce, and had no negative effect on texture or vitamin C. Irradiation at doses up to 2 kGy in combination with modified atmosphere packages is feasible for safety enhancement and quality improvement.
Technical Abstract: A study was conducted to investigate the upper dose limit of irradiation on quality of fresh-cut iceberg lettuce. Fresh-cut iceberg lettuce packaged in breathable film bags was exposed to 0, 1, 2, 3 or 4 kGy gamma radiation and stored at 3 degree C for 14 days. Carbon dioxide levels were higher and oxygen levels were lower in packages containing irradiated lettuce than those of non-irradiated lettuce through most of the storage period. Compared to non-irradiated lettuce, total ascorbic acid (ascorbic acid plus dehydroascorbic acid) content and firmness were not significantly influenced by irradiation at 1 or 2 kGy. Overall visual appearance of lettuce irradiated at 1 or 2 kGy was better than the controls. The better quality may be related to high CO2 and low O2 levels observed in the irradiated samples. Electrolyte leakage of lettuce increased with higher radiation doses and was correlated to soggy appearance. The leakage of lettuce irradiated at 2 kGy was significantly higher than that of non-irradiated lettuce after 14 days storage. Irradiation at doses of 1 and perhaps 2 kGy of fresh-cut lettuce in modified atmosphere packages is feasible for safety enhancement and quality improvement.