| More and more laboratory animal feed (LAF) are sterilized by radiation currently. However, there is few study reported on the distribution of radiation resistances of organisms contaminated in LAF. No relative information has been given for dose setting in National Standards. Therefore, a study has been carried out to gain the knowledge on the distribution of radiation resistances of the natural microbial population as it occurs in a given LAF in the present work.Original bioburden level of the given LAF is around 2×106 per gram before irradiation. More than 100 organisms were isolated and the D10 values of these isolates have been determined. To simulate the real situation of feed in packing, every 20μl aliquot of each microbial suspension for irradiation is droped on sterile filter paper piece(φ1cm) and sealed in sterile plastic bag(2×2cm2) before and during irradiation in the D10 value determination experiment. A distribution of radiation resistances, which can represent the character of radiation resistances of natural microbial population ,has been generated from the results of the study and would been used for dose setting. |
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