Evaluation of microbial quality of dried foods stored at different relative humidity and temperature, and effect of packaging methods

This study investigated the effects of relative humidity (RH) and temperature on microbial populations in dried foods (seaweed, kelp, and pumpkin) during storage. The products were stored at different RH (RH 50, 70, or 100%) and at 25 or 35 degrees C for 15 days. Overall, populations of total mesophilic bacteria, Escherichia coli/coliform, and yeast/mold in dried seaweed, dried kelp, and dried pumpkin were higher at RH 90% than at RH of 50 or 70% after 15 days of storage at 25 or 35 degrees C. Effects of packaging methods (open bag, closed bag, and airtight container) on microbial populations in dried pumpkin were also evaluated. At RH of 90% and 25 or 35 degrees C, stored closed bags or airtight containers was effective at maintaining the initial levels of total mesophilic bacteria, E.coli/coliform, and yeast/mold in dried pumpkin after 15 days. Thus, microbial survival and growth depends on storage conditions including storage temperature, relative humidity, time, and packaging methods. These results could be used for developing safe storage conditions for dried foods. Practical applicationsThe result of this study could be used for improving the safety of dried foods with appropriate storage conditions.