乾燥食品等の形状および成分の放射線殺菌に及ぼす影響

Abstract

The effect of dry condition of food materials such as spices or herbs with grain or powder were investigated for inactivation of microorganisms by gamma-rays or electron-beams. Radiation sensitivities on endospores ofBacillus pumilusandB. cereusat polished rice, whole black pepper and glass fiber filter dried with additives of 2% peptone + 1% glycerin were almost equivalent, and D10 values of gamma-rays were obtained to be 1.8-2.2 kGy forB. pumilusand 1.2-1.3 kGy forB. cereus, respectively. However, D10 value was decreased to 1.6 kGy forB. pumilusand 1.0 kGy forB. cereusin white pepper powder, and increased significantly as 2.6 kGy forB. pumilusand 1.8 kGy forB. cereusin senna herb powder. In the case ofB. megaterium, Enterobacter cloacaeandEscherichia coli, D10values were increased at all of food materials even in white pepper powder compared with glass fiber filter with additives. These results are indicating that glycerin and related radical scavengers in food components protect the bacteria such asB. megaterium, Ent. cloacaeandE. colimore significantly from effects of radiation thanB. pumilusorB. cereus. The increase of radiation resistance of these bacteria should be responsible also to the amount of oxygen penetration in bacterial cells which dried at different conditions. On the irradiation of electron-beams, radiation resistance of all of bacteria increased more significantly than gamma-rays which depending to dose rate effects on bacteria. However, increase of radiation resistance was not observed atAspergillus oryzaein all of food materials at different dry conditions.