Bleach could work. I think the fabric is color safe enough that the bleach isn’t going to bleach away the color. Best to check on a small spot first though before dunking the entire pad in bleach water. The other thing to be concerned about is whether the bleach will deteriorate the foam or deteriorate the fabric. If it deteriorates the foam the armour won’t protect you as well. If it deteriorates the fabric or stitching it will fall apart.
Check out this thread for more ideas: I’ve soiled my armour
It suggests some antimicrobial sprays that are used to disinfect medical areas.
I also like the idea of trying NO (nitric oxide) to see if that will work and be feasible (technically and cost effective).