In the spirit of reversing all advice your hear, it’s worth mentioning that a substantial portion of people genuinely are toxic once you get to know them (just look at the prevalence of abuse as an extreme yet very common example).
One’s gut instincts about someone once they open up (or you can start to get a better gauge of who they actually are) are often a pretty guide metric for whether getting close to them (or being around them at all) is a good idea.
It seems like this example would in some ways work better if the model organism was mice not bacteria because bacteria probably do not even have values to begin with (so inconsistency isn’t the issue) nor any internal experience.
With say mice though (though perhaps roundworms might work here, since it’s more conceivable that they could actually have preferences) the answer to how to satisfy their values seems almost certainly is just wireheading since they don’t have a complex enough mind to have preferences about the world distinct from just their experiences.
So I’m not sure whether this type of approach works because you probably need more intelligent social animals in order for satisfying their preferences to not just be best achieved through wireheading.
Still I suppose this does raise the question of how one might best satisfy the preferences/values of animals like corvids or primates who lack some of the more complex human values but still share the most basic values like being socially validated (and caring about the mental states of other animals; which rules out experience machine like solutions).