What are the white flecks?

[Guest guest]

Am making my 2nd batch of sauerkraut, well-covered with brine, and

used about 2 cups of refrigerated brine from batch #1. It has been 3

days now, and the brine is speckled with a kind of tiny rectangular

shaped pieces of white floating something. It isn't powdery, it

doesn't taste strong, and it wasn't there originally. It's going to be

hard to remove. Is this mold? How worried about it should I be?

Thanks,

Nance