SPORICIDAL PROPERTIES OF HYDROGEN PEROXIDE VAPOR-AIR MIXTURE (ASEPTIC PACKAGING, BACILLUS SUBTILIS SPORES, D-Z-VALUES, MATERIALS)

Aseptic packaging systems in commercial operation in the United States include as follows: (1) Dole system, (2) Brik-Pak system, (3) Combibloc system, (4) CONOFFAST system and (5) Bag-in-Box system. This is the study to investigate the effect of hydrogen peroxide vapor on the spores of B. subtilis A and B. subtilis var. globigii.;The time needed for recovering H(,2)O(,2)-injured spores on plate count agar was 7 days of incubation at 37(DEGREES)C and an additional 3 days at room temperature (22-25(DEGREES)C).;The concentration of H(,2)O(,2) in the air increased linearly with increasing in temperature. Survivor curves for spores of both organisms treated with either 35% liquid H(,2)O(,2) or H(,2)O(,2) vapor showed a significant lag period at lower treatment temperature followed by true first order inactivation as contact time increased. The higher the treatment temperature, the less time was required to achieve true first order inactivation rate. A parallel inactivation curves were exhibited for both organisms exposed to H(,2)O(,2) vapor at temperature of 60(DEGREES)C or higher. In treatment with 35% liquid H(,2)O(,2), spores of B. subtilis var. globigii were more resistant to H(,2)O(,2) than spores of B. subtilis A at all of the temperatures tested.;The D-values of both organisms were all less than one min in liquid H(,2)O(,2) treatment. Likewise, less than one min of D-values for both organisms in treatment of H(,2)O(,2) vapor, when the temperature was greater than 50(DEGREES)C. No significant difference in resistance to H(,2)O(,2) vapor between these two organisms on glass surface. Z-values were found in range of 32.6 to 52.6. Less than one min was found to be sufficient to achieve 99.9999% reduction in spores in treatment with 35% H(,2)O(,2) solution at 50(DEGREES)C, the same effectiveness can be achieved in H(,2)O(,2) vapor only when the temperature was at 70(DEGREES)C.;Modified procedures of Matsubara and Takamura were used for the determination of trace concentration of hydrogen peroxide and found to be very satisfactory in terms of constructing the calibration curve if fresh V-XO reagent was used.