Sorry for the slow reply. Just discovered the mention after a crazy busy week directing the state scholastic chess championship, making my wife Leslie's birthday present and now preparing to leave for setting up my sales table at a market in town.

Yes as @nateonsteemit alluded, silver will kill the bacteria and other microbes it comes in contact with. If there are curds which colloidal silver does not penetrate, the cultures may survive in those. Instead of using CS, you can drop a silver coin or other high percentage silver item in the jar for preservation, as has been done for over 2000 years. This would probably provide less exposure of the cultures to silver so more would survive.

Most times in life, the answer is somewhere in the middle. You could use fresh raw milk without any silver. Then add silver for preservation when you get more fresh. Then use both to maintain the full benefit of raw, but not have as much go bad.

Hope that helps.