Shelf life and sensory characteristics of baby spinach subjected to electron beam irradiation.

The use of ionizing radiation for the control of foodborne pathogens and extending the shelf life of fresh iceberg lettuce and fresh spinach has recently been approved by the U.S. Food and Drug Administration. The efficacy of electron beam irradiation for controlling foodborne pathogens has been reported. For this experiment, the effectiveness of electron beam irradiation on the microbiological and sensory characteristics of fresh spinach was studied. Total aerobic plate counts were reduced by 2.6 and 3.2 log CFU/g at 0.7 and 1.4 kGy, respectively. Lactic acid bacteria were reduced at both doses of e-beam but grew slowly over the 35 d of the experiment. Yeasts and molds were not reduced in samples exposed to 0.7 kGy whereas 1.4 kGy significantly reduced microbial counts. Gas compositions (O(2) and CO(2)) were significantly different than controls. Oxygen levels inside the spinach sample bags decreased over time; however, O(2) levels did not drop below 1% that can induce anaerobic fermentation. CO(2) levels for all treatments increased through day 4; yet 7 d after irradiation, CO(2) level differences were not significant in both control and irradiated samples. Irradiation dose did not affect the basic tastes, aromatics, or mouth feels of fresh spinach, however; hardness attributes decreased as irradiated dose increased and slimy attributes of fresh spinach were higher in control samples compared to irradiated samples.