The limits of gaseous mixture of ethylene oxide and methyl bromide are measured. These findings indicate methyl bromide is effective as a diluent which narrows the inflammable range of gaseous ethylene oxide. Then the evaporating velosity of ethylene oxide and methyl bromide are compared as they evaporate from the mixture of these compounds. This comparison shows the evaporating velosity of methyl bromide is slightly more rapid than that of ethylene oxide. This fact assures safety for the processes of fumigation. The polymerization of ethylene oxide in the mixture of methyl bromide is investigated by means of heating. It is found as a result of this experiment that the addition of methyl bromide does not influence the polymerization of ethylene oxide. The foregoing discussions lead to the conclusion that the mixture of ethylene oxide and methyl bromide have some excellent properties as a fumigant.
Thin layer chromatography with silica gel has been applied to 7 organic azo pigments (Table 1), and 17 solvents (Table 2) have been studied as developer. The results obtained were as follows: (1) Hansa Yellow (C.I. 11680), Hansa Orange (C.I. 11725), Permanent Orange (C.I. 12075), Flaming Red (C.I. 12085), Brilliant Fast Scarlet (C.I. 12315) and Deep Red (C.I. 12350) could be separated by 1, 1-dichloroethane. (2) Hansa Yellow (C.I. 11680), Permanent Orange (C.I. 12075), Flaming Red (C.I. 12085), Toluidine Red (C.I. 12120) and Deep Red (C.I. 12350) could be separated by 1, 1, 2-trichloroethane.
We observed that cooked rice containing DBT kept better than the control and then demonstrated in vitro that growth of a sporeforming bacterium which was isolated from spoiled rice and was guessed to play a leading role for the spoilage, was checked in the medium saturated with DBT. The mechanism of the observation is clarified.
The bacteriostatic action of DBT was demonstrated for following bacilli in liquid and solid media. 1) B. cereus OM-1, 2 and 3, causative agents of skim milk poisoning in Okayama prefecture, reported by Suzuki and Kawanishi in 1961. 2) B. pantothenticus NN, a causative agent of the softening deterioration of fish sausage, reported by Yokoseki et al. 3) B. thiaminolyticus Matsukawa et Misawa and B. aneurinolyticus Kimura et Aoyama known as strains of aneurinase bacilli. 4) B. mycoides, B. megaterium and B. firmus, laboratory strains.
“Close system” and “flow system” are proposed as the test methods for fumigation against the microorganisms. When the “close system” is employed, the volume of fumigation vessel used for the test should be 1 to 2 liter and the fumigants should be injected into this vessel at the gasphase. When the above method is in operation, the gas distribution in this vessel becomes even immediately. Therefore, the quantitative expression of a sterilization effect is possible. When the “flow system” is employed for the test of a fumigant with a low boiling point, the apparatus to be used is shown as Fig. 2. On the other hand, the apparatus illustrated in Fig. 3 is used for fumigants with higher boiling points. These apparatuses of Fig. 2 and 3 are recommended for quantitative expressions such as comparison of the sterilization effect of various fumigants or microorganisms and the probabilitical study of sterilization mechanisms.