The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Cross Contamination and Your Sourdough Starter

theweissman's picture

Cross Contamination and Your Sourdough Starter

Hey everyone! So yesterday I started a kombucha ferment and stored it next to my sourdough starter for an Instagram photo. Shortly after, one of my friends sent me an article about how storing ferments closer than 3 feet to each other can cause "airborne cross contamination". Now while this sounds like it may be true, there was really no scientific data supporting what they were saying. Do you think that it is truly necessary to separate a kombucha ferment from my sourdough starter? They only sat next to each other overnight so I hope that nothing happened within those few hours if this really is true... Anyway, let me know what you guys think about this. Is this fact or is it just a bunch of weird unproven myths? 


Here is the article:

Lechem's picture
Lechem (not verified)

...there is cross contamination? You'll just have a more complex sourdough starter or kombucha with more strains of yeast and bacteria.

That is the worst scenario. Not so bad.

Best scenario is that only yeast/bacteria strains which can exist in a sourdough starter / kombucha can exist in either starter.

netfan's picture

Sourbucha startment ?


clazar123's picture

Cross contamination is a given unless you practice extreme high level contamination prevention measures (think funny suits with an oxygen tank,lab hood and Bunsen burner). The benefit of cross contamination is that my kitchen is now populated with organisms that cause fermentation before molding. My grape juice sometimes ferments in the pitcher for delicious, carbonated grape kefir. I probably contaminated the pitcher when I fed the milk kefir first and then poured the juice for my juice kefir. Fruit in my refrigerator doesn't mold-it generally ferments first.  All cultures will evolve over time as new "neighbors" move in. Usually it is gradual and not noticed. Rarely it is obnoxious or dangerous.


DesigningWoman's picture

To "trap" stuff that's "in the air" and engender something unique as it evolves and develops? I think it's a pretty cool phenomenon.

Enjoy the ride!

Our Crumb's picture
Our Crumb

Your komboucha is saturated with bugs adapted to and thereby successfully competitive in whatever you feed them to maintain your brew. Your sd starter is saturated with bugs that are adapted to and successfully competitive in whatever you feed them as well. That even a cloud of stray bugs crashing either party would have any chance of reproducing at a rate that would threaten the dominance of the resident populations in either culture is decidedly remote.

Worry about something else.  

theweissman's picture

Yep, this was exactly what I was thinking. I appreciate everyone taking the time to give me their input!