Assessment of microbial safety and quality changes of brown and white cooked rice treated with atmospheric pressure plasma.

The microbial and physicochemical properties of brown and white cooked rice treated by atmospheric pressure plasma (APP). APP was produced (250 W, 15 kHz, ambient air) and applied to brown and white cooked rice for 5, 10, and 20 min. The 20-min plasma treatment reduced in bacterial counts by 2.01 log CFU/g when cooked rice were inoculated with Bacillus cereus or Escherichia coli O157:H7. The pH of the brown cooked rice was decreased by the 5-min plasma. The hardness values of APP-treated brown and white cooked rice were lower than untreated samples. The reducing sugar contents of brown and white cooked rice were significantly higher than those in untreated samples. Lipid oxidation of APP-treated brown and white cooked rice were higher compared to untreated samples. These results indicate that APP improves microbial quality, although further studies should be conducted to change the physicochemical qualities of brown and white cooked rice induced by APP.