Resistance Of Salmonella Paratyphi On The Effect Of Gamma Irradiation

S. paratyphi was exposed to single and fractionated doses of gamma irradiations i.e. 0; 0.15; 0.30; and 0.45 kGy. The fractionated doses were given in various intervals i.e. 0.1 and 3 hours. The doses rate was 0.65 kGy/hour. The optimum growth temperature was 30 celcius centigrade and the concentration of cell suspension to be irradiated was 3 exp.8 cells/ml. It seemed that nutrition and fractionated doses had a synergism action on the resistance of Salmonella. The comparison among interval time of irradiation of 0, 1, and 3 hours at the dose of 0.15 kGy were 83:87:91; at the dose of 0.30 kGy were 72:74:74 and at the dose of 0.45 kGy were 64:67:70. When we compared the interval time of irradiation of 1 and 3 hours the cell resistance was decrease in the cell suspension without nutrition. The comparison among interval time of irradiation of 0, 1, and 3 hours at the dose of 0.15 kGy were 79:82:77; at the dose of 0.30 kGy were 58:65:63 and at the dose of 0.45 kGy were 35:46:43. (author). 11 refs, 5 tabs