The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Whole grain bread contamination?

Hoko's picture

Whole grain bread contamination?

Hello everybody, you seem to be advanced bread makers so I hope you can help me a little. I have been making this sourdough wheat/rye bread for quite some time and I love it very much but it seems to give me some intestinal problems. My main question is whether it is possible that some undesirable microorganisms (even yeasts) present in sourdough (and thus the bread) could actually survive the baking (1 hour 10 minutes at 200 celsius, usually starting with cold oven). I don't take the best care of my sourdough, I keep it in the fridge, feed it once every one or two weeks with whole rye flour. It gets quite disgusting sometimes with dark liquid separated on the top. But then I just mix it with new flour. And the bread is always good, it's a three step process usually spread over two days (much less in summer). I imagine the sourdough being contaminated with I don't really know what. Any ideas? Thank you...

mrfrost's picture

Are you sure the bread is the cause of your symptoms?

Have you eliminated it from your diet, for a decent period, and been symptom free?

Have you tried a diet of only store bought white bread? Store bought whole grain? Sourdough that you are not managing?

It may not be so simple to pinpoint the (exact)cause of your symptons? Has this been diagnosed by a professional?

Hoko's picture

Hi, thanks for the answer. I'm pretty sure that I don't have problems with other baked goods. I generally enjoy good health but my bread is somewhat problematic. Maybe it's just too "dark" even though I always use some white flour to make it lighter. But I wonder whether the sourdough could be contaminated with something that actually survives the baking.


mrfrost's picture

Sourdough... white flour... "dark" flour... who's to say? It often takes a systematic approach to find the precise cause of symptoms created by one's diet. You still did not say if you singly eliminated your "suspects", and been symptom free.

My late sister had an aversion to sourdough, among certain other foods. Said they bothered her "stomach". She was later diagnosed with breast cancer, treated, and "cancer free" for 5 years. A little after 5 years, she began having more severe "stomach" pains. Doctors eventualy found a "spot" on her lower spine. The cancer had been hiding there. They irradiated the little spot away. They never said(overtly), and she never accepted that this may have been the cause of the stomach pain. We all prayed it wasn't. 

The "stomach" pains persisted, in short order(9 months) the cancer overwhelmed and took her. Was this "spot" in her lower back the cause of the "abdominal" discomfort all along? I maintained it probably was, but I am not a doctor. I don't think it's too much of a stretch to say it was.

Not trying to alarm you in any way. Just trying to show that sometimes the causes are simple(eliminate suspects), sometimes not.

Certainly your "contaminated" sourdough as the cause could be revealed by eliminating it from your diet(or add it to others diet).

Good luck.


bakinbuff's picture

It can be quite difficult to tell what exactly is causing a particular symptom, without completely eliminating it from your diet for at least 2 weeks, and until you are free from symptoms, then re-introducing it for a day, and keeping a record of what happens in the week or more following (if you experience the same symptoms again, then keep records until you are symptom free again).  This is one way to really conclusively ascertain the cause of a digestive problem.  However, if you are worried about the health of your starter (although the dark liquid is most likely just "hooch" which is quite normal, and I get it in my starter if the hydration is too high), then the easiest way to check that out is to start a new starter. 

Unless you have an amazing starter that you have nourished for years and years and don't want to get rid of, it is simple enough and only will take you a week or so to have a new useable starter.  Also, maybe your stomach is fed up of rye and wants to have something else for awhile?  You could start a wholewheat/white flour starter, keep your rye starter in the fridge giving it a feed every few weeks, and just bake with the new one for awhile.  Then, after using the other starter for a month or two, try using the rye again and compare the smell, appearance, taste and digestive after-effects of the rye bread with the wholewheat/white flour starter. 

yozzause's picture

I dont know whether the starter is up setting your stomach but it should certainly be pleasing to the eye the bread looks magnificent,try it on a few more guine pigs and see how they cope with it.

I'd be happy to try a slice or two for a couple of weeks in the name of research. Perhaps the start of an intolerance to rye!

Regards Yozza

Hoko's picture

I'd be happy to test it on you :)

Hoko's picture

Thanks for your comments bread folks. I'm certainly trying the bread on others but they don't eat as much of it. I'll keep experimenting. There are just million factors involved but I'll start with lighter bread because this one is fairly heavy. And I'll try another sourdough. And if that doesn't help I'll do the yogic salt water intestinal flush... :)


Mise En Place's picture
Mise En Place


Very, very few food-related bacteria or yeasts that would cause intestional distress will survive anything > 185F for longer than 5-10 minutes.  Since most hearth breads bake until 205F or so, I would think that this would not be your problem.

I would concentrate on either allergic reaction or some other contamination besides bacterial (industrial?).  The other replies are good, cut out the bread for a couple of weeks to see.   Another option is to change the source of your raw material (another brand of flour?) to see if there is the possibility of contamination there.

Do you react the same with the first few slices vs. the end of the loaf after it's been stored for a period of time.  This may suggest a reaction to molds.

Anyway, just some thoughts. 

Gourmand2go's picture

The note-taking approach makes sense to me, and if you have someone objective to watch you and point out any unconscious habits that might be exposing you to something you take for granted but that might be causing a reaction would help.

You could have a buildup of toxins in your starter.  Rye is notorious for microorganisms including ergot; a symptom of ergotism is diarrhea. 

Any hallucinations? ;)