Sensitivity of microorganisms be distributed through Japanese tea manufacturing process by radiation

The number of bacteria adhering to Japanese tea is 107∼108 cfu/g in picked fresh tea leaves (almost radiation irresistance), decreasing every heat-treatment in manufacturing process to 103∼104 cfu/g in tea on the market (only radiation resistance). Still more, its decreasing one figures after half a year by effect of anti-bacterium component contained Japanese tea. The number of fungi adhering to almost samples is below 50cfu/g, but that adhering to some powdered tea is 102 cfu/g. At heat treatment (80degC, 15min), the number of bacteria decrease very little. The other side, by EB-irradiated treatment (2kGy), its below 102 cfu/g (D10-value; 1.4∼3.8kGy). The needed dose to decrease 102 cfu/g is 0.9∼2.5kGy. (author)