Benchmarking the Minimum Electron Beam (eBeam) Dose Required to Achieve Sterility of Space Foods
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The safety, nutrition, acceptability, and shelf life of space foods are of paramount importance to NASA, especially on long-duration missions. Since food and mealtimes play a key role in reducing stress and boredom of prolonged missions, the acceptability of food in terms of appearance, flavor, texture and aroma can have significant psychological ramifications on astronaut performance. The FDA, which oversees space foods, currently requires a minimum dose of 44 kGy for irradiated space foods. The underlying hypothesis is that commercial sterility of space foods could be achieved at significantly lower doses. Lowering the minimum dose can positively impact the visual appearance, sensory attributes, nutrient content, and overall acceptability of space foods. The focus of this project was to use beef fajitas (an example NASA space food) and employ eBeam processing to benchmark the minimum eBeam dose required for sterility. A 15 kGy dose was able to achieve an approximately 10 log reduction in STEC bacteria, and 5 log reduction in Clostridium sporogenes spores. Furthermore, accelerated shelf life testing (ASLT) to determine sensory and quality characteristics under various conditions was conducted. Using GC/MS-olfactory analysis, numerous volatiles were shown to be dependent on the dose applied to the product. Furthermore, concentrations of off –flavor aroma compounds such as dimethyl sulfide were decreased at the reduced 15 kGy dose. The long-term goal of this project is to collect empirical data to enable NASA to petition the FDA to lower the minimum dose from 44 kGy to significantly lower doses.
Bhatia, Sohini Sanjay (2016). Benchmarking the Minimum Electron Beam (eBeam) Dose Required to Achieve Sterility of Space Foods. Undergraduate Research Scholars Program. Available electronically from