Citrus-smelling sourdough starter I have a batch of King Arthur sourdough starter that I mixed up several months ago and have been using ever since. I keep it in the refrigerator and feed it with 100 g of AP flour and 100 g of water once a week. I have made several hybrid loaves with it with no issues.
I have noticed that at the end of the week when I am ready to feed it, it seems to have an orange-pink coating that has a strong citrus smell. I assume that it is some kind of fungus. I live in north Florida. It does not seem to be harmful in any way; I've made several loaves since I noticed it and have never gotten sick.

Any idea what it might be?

UPDATE
Here is a picture of the starter. In the lower left, you can see an orange tint.
I'm pretty confident you can get rid of that with the Ed Wood "washing" process. 


Stir hooch into starter. This stuff the microflora make to protect themselves.
Increase the volume 3-5 times with water
Stir until homogenous
Pour off 4/5ths of it
Tip in flour and stir until homogenous
If not a consistency you like then add more flour or water
Wait until it has risen double or triple
Repeat several times


Lactobacilli and yeast are just a lot more active than moulds when at room temperature, they will outcompete the mould spores. If there were a toxin you'd just be diluting it, but I've heard of people reviving prized cultures that had gone completely black.

Good luck!