Effect of various treatment conditions on scrapie infectivity in tg a 20 mice. Kaplan-Meier survival curves were generated to compare treatment conditions to 10-fold serial dilutions of RML scrapie in tga20 mice. Treatment with PK alone had no effect on infectivity. Treatment with SDS alone or SDS followed by PK (SDS → PK) yielded an approximate 2 log10 reduction in infectivity with 0% survival. Similarly, treatment with either SPC-PL or SPC-PH alone followed by exposure to PK resulted in a 2–3 log10 reduction in infectivity. The combination of SPC-PL or SPC-PH with SDS followed by PK resulted in a 4–5 log10 reduction in infectivity with 73% and 88% survival, respectively. Abbreviations: SPC-PL or H, low or high concentration sodium percarbonate-based product; SDS, sodium dodecyl sulfate; PK, proteinase K.