How Do I Protect My Pit Bulls??

[Copper'sMom]

I am moving from the country into town. So now I will have to walk my dogs in public on a daily basis. My question is:
How will I protect my muzzled dogs from loose dogs on the street??? It's bad enough my Zoe has fear aggression problems, but if she is leashed and a dog is loose, it will make it much worse for her.
I wouldn't want to hurt another dog, but at the same time I have to do what I can to protect mine - afterall, they will be blamed just for their existence!
Would pepper spray seriously injure a dog? I want protection, but I don't want to hurt the other dog unless it is aggressively attacking!