Major Kahm Yeast - How can I prevent this in the future?

Everything in the prep area needs to be clean and the veggies washed under clean, running water before making the mash. Once the mash is in the fermenting vessel and the innoculant is added (leaving plenty of room for expansion) put the lid on and don't take it off until ready to do the final processing. Removing it up to check the pH, add to, or remove from the mash, or let out excess pressure just lets in cross-contaminants. If you don't have an airlock fitted to the lid of your fermenting jar, crack the seal just enough to vent the excess pressure... you won't be able to miss when that happens because you'll hear the hiss of escaping gas... then crank the lid back down again immediately. Carbon dioxide from the ferment displaces the air inside the jar, and this is a good thing... you just don't want so much that it breaks the jar. Adding a teaspoon of Agave nectar or honey to the mash when you add the innoculant ensures that if your lacto-culture is viable it'll have enough food to begin to reproduce immediately, and there'll be no need to open up the fermenter to add more innoculant. Most vegetables don't contain very much sugar and this little boost helps a lot.
 
Hope this helps

I had a couple jars that started to get the slightest hint of kahm yeast, I shook the jar up coating everything again with the brine and lactic acid...which effectively stopped it.  The yeast doesn't like the harsh environment of the brine/acid, so it grows on the very surface...which is also where the highest concentration of O2 is likely to be.  Giving it a shake ensures that anything even thinking of growing on the surface, doesn't.   So as long as you don't open it, and give it a shake every couple days at first, then every few weeks/month later, you should be good.  Of course if you use an airlock you might not be able to shake it up, it will just plug it up.  I don't personally use airlocks, I just leave them cracked a tiny bit to vent during the fermentation (first couple weeks), then crank them down when its done.  As long as its not too loose, the positive pressure inside the jar from the fermentation will ensure that gases only flow out, not in.