by Marion Nestle
Jun 11 2011

The science and politics of E. coli in sprouts

German authorities now say that  sprouts grown on an organic farm in Lower Saxony are the source of their E. coli O104:H4 outbreak, now responsible for more than 30 deaths and 3,000 illnesses, 750 of them severe kidney disease.

The epidemiological studies point to sprouts after all.

Sprouts, as I mentioned in an earlier post, are a prime suspect in microbial outbreaks.   They have been implicated in many outbreaks in the United States.  This is because sprouts are sprouted from minute seeds that are hard to clean, as shown in this microscopic view:




As Food Safety News explains in a long discussion of this problem, the seeds need to be dumped in bleach to kill bacteria.  It’s also a really good idea to test the wash water to make sure it is free of pathogens.

The seeds are sprouted in water at room temperature, “a warm, moist climate — just perfect for a bacteria’s social life and subsequent reproduction.”

The FDA has been aware of this problem for a long time, as shown by this brief chronology:

The Food Safety Modernization act passed last year finally gives FDA the authority to require food safety controls for sprouts.

The German outbreak ought to be a wakeup call for this industry in the United States.  Sellers of bean sprouts market them as health foods but say little about how unsafe they are if eaten raw.

It also ought to be a wakeup call for consumers.  If you aren’t absolutely sure the seeds come from a clean source, cook your sprouts.

  • Anthro

    I should have known you’d be on to this without my heads up on the “feedback” page.

    A timely post as a comments page of the NY Times a couple of days ago had gobs of people advising everyone to simply “grow your own” sprouts. I posted your advice, but quite late in the game so it probably won’t be read much.

    I’ll be cooking mine from now on, for sure.

  • RB

    So sprouts are a good carrier of bacteria. Sprouts were contaminated with E. coli. E coli comes from animal guts. So what was the E. coli source in this case?

  • The thing is I suppose, sprouts aren’t quite the same if you cook them. Mung bean sprouts, yes, but alfalfa? And is it really any better if you grow your own? The seeds might already be infected. Some cities add chlorine to the water but not all. Maybe that vegetable wash you find in some organic food shops is the way to go.

  • Tom

    Oh boy, this should be great news for the Raw Food movement.

  • gesa

    you are right, it is a desasaster – not only for the raw food movement. As my organisation works in consumer communication we are running an internet forum “ehec and food”. On our website people get answers from nutrition experts for free. I can report that lots of people over here in Germany are profoundly worried. They distrust not only sprouts but also raw fruits and veggies in general.
    German administrations meanwhile assume that this outbreak is caused by humans. The little organic enterprise which has produced the sprouts is well known for its good hygienic standards. Overmore it was examined twice. At the very beginning of the outbreak and later again – both times with negative results. When I am right they did not found any EHEC bacteria on site. Last friday finally they detected EHEC in a bag of sprouts which came from this enterprise and belonged to a family which was infected by EHEC. The source of the contamination seem to be two employees, who were infected by EHEC without any symptoms occuring. For me the moral of the story is: Eat locally and clean your hands carefully before raising your own sprouts….

  • I guess I must be just one incredibly lucky guy to have eaten sprouts for 47 plus years without a single incident.

    But it is true that if there was even the slightest hint of rot or mold, I would just toss the sprouts and grow or buy a fresh batch. And I do have a habit of thoroughly rinsing sprouts before using them.

    But then maybe it’s because I have only taken antibiotics about 3 times during that 47 years and my internal microbial world is happy and active.

    Don’t panic, but be sensible and prudent.

  • Sam

    E. Coli is such a charged topic on the organic/local vs mass-produced debate, that people like RB want to concentrate on cattle and ignore the truth about the safety of sprouts. Sprouts have been recalled for Listeria and Bacillus Cereus. These are bacteria that are not from cattle, but are naturally found in the soil, and for whom the sprouting process provides, as Marion mentioned, an ideal environment for growth. These bacteria, especially Listeria, are dangerous for pregenant women, children, and the elderly. So even if you some how manage to keep sprouts free of cow poo, you will still have the risk of these other pathogenic bacteria. Sprouts are not safe raw, if you want to eat them, cook them!

  • Cathy Richards

    @Gesa — washing your hands before growing your own sprouts is not an answer to the chronic issue of bacterial problems with sprouts. It is inherent in the growing process — clean hands or not.

    In this case, the bacteria was E.Coli — good water source and clean hands will help with that, but not with many other contamination sources.

    As the song says: “Dust (and bacteria) in the wind”.

    With all food, raw isn’t always better. Cooked is often better.

  • Gesa

    thank you Cathy for the clarification. I agree that clean hands are not an answer to bacterial problems at all. I wanted to stress that they are an important transmission path, which often is underestimated, especially in this case. I agree to Sam that there are sensitive population groups like pregnant women which at least should avoid eating raw sprouts. But there is always an unpredictible risk remaining, as you can find Listeria in pasteurized cheese, as well. In our sprout-case they are discussing today if the seeds of the sprouts were contaminated and sickened the employees of the farm. Now they are advising people to avoid every sprout, no matter of origin. The puzzle is not complete yet.

  • Cathy Richards

    David Katz has an excellent article about this issue this week. He points out that although it’s a veggie that is contaminated, the contamination is all about meat. The E.Coli in this outbreak almost certainly originated in — to paraphrase the never shy Dr. Katz — abused, drugged, mass produced/slaughtered/distributed animals sold cheap to cheap uncaring humans.

    Healthy cattle, fed grass not grains, do not tend to host pathogenic E. Coli. Grain fed cattle do. Cows don’t choose to eat grain, we feed it to them so they’ll grow and fatten faster, where we want them to.

    Unfortunately, we’re more likely to blame the sprout than blame ourselves.

  • I feel this Alfalfa sprout being blamed by them , is a cover up of course you can eat the fragile Alfalfa sprout. From a field it would be filty and like even they said in there article , if you wash them before you package them for market they would wilt , because there not supposed to be rinsed until time of ingesting them they said well thats because there out there with manure and everything where there not supposed to be… So they admitted themselves, its not a good practice for us to eat there field to table Alfalfa sprout. Alfalfa grass it becomes after 5 days while still in the ground or any soil for that matter. then can be fed to cattle. but there using round up ready now on everthing look it up. you will really worry then about all your food , corn everything . No, Alfalfa sprouts should be grown at home rinsed often while in process of growing which takes a few days then kept clean in a jar in the refrig. They are trying to get our eyes off of Monsanto Gmo and all they are up to and use this Sprouts talk because the dummys dont know how to grow them. and ruin Organic gardening intellegent people who can see through there leading people of the danger they have created themselves with Ecoli, Round up ready . look into that!!! i eat alfalfa sprouts all the time , home made only never store bought ones. besides wheat grass which is king of the grasses, alfalfa is 2nd to wheatgrass there just making people afraid of food so we eat there death food. Alfalfa spouts are great unless they have managed to have GMO’d it and added pesticides in the seed. Oh Oh. They are trying to take God given Herbs from us too. Just like they did to the Naturapaths , so they could patent them and make money by adding other chemicals to them , and they hate the fact that people are getting well from them so they have to stop that . like there doing in Europe with the herbs , i guess they will arrest us one day for growing God given herbs for the healing of the nations. the bible said.

  • Ecoli originates in the bowels of animals and humans not in fruit or vegetables , with all the antibiotics they give to the indoor cows and other animals they have come resistant and a super strain has developed. Just like there now are antibiotics that wont wipe out some human ailments now , because we have superstrains. There are so many things that have been messed with , grain that has been fertilized with sources of manure in question . If they would study the organisms of soil to understand it before putting poisons in the earth soil and expecting anything to happen , killing off earth worms, killing the good microorganisms killing minerals such as selenium, then for disease controll they shoot the animal with 60 to 80 different things antibiotics and by the way we take all that in our bodys from them. I like the way they always sound like the savior , \ALERT sprouts are dangerous killers i am sorry but they them selves are the killers. the ones fooling with the wonderfull soil that has magic in it to grow healthy plants , green manuring is the answer to disease controll and learning to grow side by side insect repelling plants etc. the study of that is so long over due and when taken up , these people come into the picture and put a stop to it , they dont want us to have anything but poisons and using vile methods for our food supply. and keeping animals in the most horrible conditions, abusing them . For veil that people eat th
    the baby calf right after birth is taken away from its mother and putt into a short metal container stall so that it looks one way and cant turn around or move so it wont rub its body on anything as to keep its tender pink color which is called veil so it looks good in the market without any blemishs, no nursing taken straight away from her. and the mother she is destined to the slaughter house. in the most unhumane way of killing it. The truth is, we were going the right way consuming vegetables and fruits , nuts and seeds, and some grain and finding that diseases can be cured from this fare. That is why the big mess now the scare about vegetables and fruit and grain, and sprouts , and it is them that are CONTAMINATING all of it. Not the local farmers or small farms , they are in fear that Round up ready is going to cross pollunate there clean organic crops. we have to open our eyes and make them stop messing with us and our food and the earth.

  • Debbie Murphy

    For those of you who don’t know, Obama bowed to Monsanto again, and is allowing deregulated planting of genetically engineered alfalfa. As if alfalfa (weed-like in growth) needs that horrific poison Roundup sprayed all over it to kill weeds! It’s non needed but Monsanto as usual convinces farmers they must go with the latest “technology!” Note: alfalfa pollen can cross 5 miles away. Those of us who feed alfalfa hay to our animals are devastated. Roundup has been shown as a possible cause of infertility, cancer etc! It will hurt our animals and it will hurt us, is my opinion. Were these sprouts GE in the e.Colin outbreak, I wonder?

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