I'm going out of town for a week leaving tomorrow, so I'm ending the experiment today. While the two counter cultures got a lot more acidic - about the same as their healthy counterparts - there was something else going on in them. They had a really nasty background taste. It was like Ischia or Camaldoli should taste but with some rotten stinky culture blended in. For kicks and grins, I cultured some straight KABP (what I'd been feeding them) and it wreaked. I didn't taste it, but it seems reasonable that is what contaminated the counter cultures. I can't say if the Ischia and Camaldoli would have regained control after some period of time, but as of today, they were certainly compremised. Given every advantage, (weak, next to death culture, heavily diluted in when feeding [1 part culture to 10 parts flour]), it does appear that a rogue culture can indeed get a foothold - at least temporarily. If I was to try it again, I would not dilute the counter culture - just add flour to it over time to bring it back - that way it would have a much more acidic, antibiotic, environment that might make it more difficult for the contaminants to get a foothold.