Example 2
Thuricide BT Caterpillar Control (Southern Ag) was used as the source of viable Bacillus thuringiensis spores (6 million spores/mg). A dilution series was produced from Thuricide BT to show that the material is viable and could be readily cultured on Petrifilm plates. Three DEE chemical compositions were evaluated: (1) about 0.06 M copper (II) chloride in water, (2) about 1 wt.-% surfactant and about 10 wt.-% PCSR in water, and (3) about 1 wt.-% surfactant and about 1 wt.-% PCSR in water. OxiClean was used as the PCSR and Tween 80 as the surfactant. During testing of each DEE composition, the DEE composition was added to the spores to yield a 1:100 dilution of spores and exposed to 2.45 GHz microwave radiation for about 10 s. After exposure, the cells were centrifuged and washed to remove the DEE composition and then plated on Petrifilm and cultured for 24 h at 30° C. When using each of the three DEE compositions shown above, the decontamination method destroyed BT spores at 6-7 log kill levels and demonstrated the efficacy of bleach-free treatments.
