The Fresh Loaf

A Community of Amateur Bakers and Artisan Bread Enthusiasts.

Food poisoning? feeding poolish like sourdough starter.

hajonnes's picture

Food poisoning? feeding poolish like sourdough starter.


I was going to bake for a couple of days and was running low on yeast so I thought I could use poolish and feed it like a sour dough starter. I.e. 100% hydration and feed it every day.
One thing was a little different though, a couple of times I used up almost all the preferment, only leftovers on the sides on the jar were left and I used that as a starter for the poolish.
Since I used so little starter to approximately 50g of flour I might have changed the flora of the starter I'm speculating.
I stored it both cool at approximately 12C ~53F and at room temperature 22C ~71F. I have not been rigorous with the temperature since a lot of poolish are done in room temperature.

Now 4 or 5 days into my baking the last batch of bread and pizza where a little strange taste wise.
The dough was a little too extensible for the pizza, like too much enzymatic activity or over fermented.
The bread did not rise so well so the bread was a little compact. 
I thought that perhaps I had started a sour dough culture and we all ate of it.

I feel a little bad in my gut and my two children feel also feel the same and they did throw up a little, but not much.

What is your take on it?

What is the correct way of maintaining a yeast culture? Can it be done?
The concept of "old dough" preferment, is that not what I did?

Sabina's picture

I think a culture made with just commercial yeast needs to be kept in the fridge. Sourdough has the sour bacteria that keep other organisms out of the dough. Commercial yeast doesn't have that, and since you noticed changes in your culture, I'd say it has changed its composition, and it might very well not be safe to eat.

That said, I think chances are good it's in the process of changing into a sourdough culture. If you want one, just keep feeding it regularly until you stop seeing changes. I wouldn't bake anything I intend to eat with it until it's stabilized, though. Also, you will want to feed it more than once a day. Once it's stabilized, you can keep it in the fridge and feed it less often, but at room temperature, it will need to be fed 2-3 times per day. Feeding just the scrapings in the jar shouldn't be a problem. I do it all the time with my sourdough.


tpassin's picture

The key difference here is that a sourdough starter is acidic and that inhibits the growth of undesirable organisms including ones that can make you sick.  When a new sourdough culture is being created, after the first day or so there may be some activity to be seen but it's likely to be those other organisms.  Over several days the acidity increases, and eventually only the desired bacteria and yeast will be able to thrive in the acidic culture.

You may have hit the middle ground, having encouraged the growth of unwanted organisms but not achieved a low enough pH to suppress them.

Obviously people who use a poolish aren't getting sick all the time; they use their poolish with 12 or perhaps 24 hours.  I have made an unleavened dough and aged it on the counter for a day before mixing with sourdough starter, and all was well.

I wouldn't be so sure about leaving it longer, though.


Abe's picture

What about salt rising bread which uses food poisoning causing bacteria to make bread and it doesn't cause sickness?

Could it just be a coincidence?

Once baked it should be fine but there are also issues of cross  contamination. 

All that being said sourdough starters before maturing also have bad bacteria. Once it has become acidic and stable the bad bacteria are killed off. So making a sourdough starter using yeast is fine but make sure it's ready. Perhaps use it for the first day or two but then hold off till the process is complete. 

Davey1's picture

If it's created and stored properly - no problems. That doesn't mean there is no problem with certain individuals. A simple test would tell. Enjoy! 

hajonnes's picture

Thanks for all replies. Yes sourdough seems the way to go.