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Superbugs in Conventional vs. Organic Chicken

The level of multi-drug antibiotic resistant bacteria contamination is compared between meat from animals raised conventionally and certified organic meat from animals raised without being fed antibiotics.

January 8, 2014 |
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Supplementary Info

Sources Cited

F. C. Tenover. Mechanisms of antimicrobial resistance in bacteria. Am. J. Med. 2006 119(6 Suppl 1):S3 - S10; discussion - S62 - S70.

R. Sykes. The 2009 Garrod lecture: The evolution of antimicrobial resistance: A Darwinian perspective. J. Antimicrob. Chemother. 2010 65(9):1842 - 1852.

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S. Zhao, K. Blickenstaff, S. Bodeis-Jones, S. A. Gaines, E. Tong, P. F. McDermott. Comparison of the prevalences and antimicrobial resistances of Escherichia coli isolates from different retail meats in the United States, 2002 to 2008. Appl. Environ. Microbiol. 2012 78(6):1701 - 1707.

J. C. Stuart, T. van den Munckhof, G. Voets, J. Scharringa, A. Fluit, M. Leverstein-Van Hall. Comparison of ESBL contamination in organic and conventional retail chicken meat. Int. J. Food Microbiol. 2012 154(3):212 - 214.

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Images thanks to Nottingham Vet School via Flickr and Jacopo Werther via Wikimedia Commons. Thanks to Ellen Reid for her image-finding expertise and Jeff Thomas for his Keynote help.


One of the most concerning developments in medicine is emergence of bacterial super-resistance. Resistance to not just one class of drugs, like Penicillin, but resistance to multiple classes of drugs, so-called multi-drug resistant bacteria. In the 2013 FDA retail meat report more than a quarter of the Salmonella found contaminating retail chicken breasts were resistant to not one but five or more different classes of antibiotic treatment drugs.

Throughout history, there has been a continual battle between humans and pathogens. And for the last half century that battle has taken the form of bugs versus drugs. First we developed penicillin, and the US Surgeon General declared "The war against infectious diseases has been won." However, the euphoria over the potential conquest of infectious diseases was short lived.

In response, bacteria developed an enzyme that ate penicillin for breakfast. Literally, an enzyme that breaks down penicillin. In fact they can excrete large quantities of the enzyme and so can destroy the drug before it even comes into contact. Ah so we developed a drug that blocks the penicillin eating enzyme. That's why you may see two drug names— one is the antibiotic, and the other is a drug that blocks the enzyme the bacteria uses to block the antibiotic, but the bacteria outsmarted us again, and so it goes back and forth. However hard we try and however clever we are, there is no question that organisms that have been around for 3 billion years, and have adapted to survive under the most extreme conditions, will always overcome whatever we decide to throw at them.

So we went from 1st generation antibiotics, to second generation antibiotics, to third generation antibiotics. But now we have bacteria that evolved the capacity to survive our big-gun third generation cephalosporins like ceftriaxone, which is what we rely on to treat life-threatening Salmonella infections in children. Where are these super-duper-superbugs found? Almost 90% were isolated from chicken carcasses or retail chicken meat.

But what if you only ate no-antibiotics-added organic chicken? A comparison of these multidrug resistant bacteria in organic and conventional retail chicken meat. The first such study ever published. All of the conventional chicken samples were contaminated, however, the majority, 84%, of organic chicken meat samples was also contaminated." So 100% versus 84%. Organic is definitely better, but odds are you're still buying something that could make you sick.

But where do these antibiotic resistance bacteria come from if they're not using antibiotics on organic farms? A possible explanation is the day old chicks come from the hatcheries already infected before they arrive, or they become contaminated after they leave in the slaughter plant. Organic chickens and conventionally raised chickens are typically all slaughtered at the same plants so there may be cross-contamination between carcasses. Finally, factory farms are dumping antibiotics and antibiotic resistant bacteria-laden chicken manure out into the environment. You can pick up antibiotic resistance genes right out the soil around factory farms.

So even meat raised without antibiotics may be contaminated with multi-drug resistant bacteria.

In a cover story in which Consumer Reports urged retailers to stop selling meat produced with antibiotics, they noted some store employee confusion, although maybe they weren’t so confused after all. An assistant store manager at one grocery store, when asked by a shopper for meats raised without antibiotics, responded, “Wait, you mean like veggie burgers?”

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

I addressed this issue previously in videos such as:

Isn’t it illegal to sell meat contaminated with dangerous bacteria? Unfortunately no. See why in my video Salmonella in Chicken & Turkey: Deadly But Not Illegal. Reminds me of the case I wrote about in Supreme Court case: meat industry sues to keep downed animals in food supply.

If you haven't yet, you can subscribe to my videos for free by clicking here.

  • Nevo

    I am hoping someone can tell me if the resveratrol in red grapes is degraded or eliminated when cooking? My friends tell me that the pasteurized organic grape juice I sometimes drink has no resveratrol remaining due to the heat of pasteurization. For some reason I am a bit skeptical.

    • Phil

      Your friends are correct; little or no resveratrol remains after pasteurization. But the point is moot since grape juice has such a small amount in it to begin with. To get the amount that Sinclair used in his experiments would require you to drink hundreds of bottles of wine a day. What a headache you’d have!

    • Phil

      (continued from below) Don’t think you need to take 250mg of resveratrol to get the benefits found in experiments. The drug worked by activating the SIRT1 gene. You can get the same effect by intermittent fasting. There are two versions of this regimen. You can either limit your calorie intake to 500 calories a day and then eat as much as you wish on alternate days (and probably loose quite a bit of weight) or you can simply eat each day during an eight hour window, say from noon to eight. One gets used to skipping breakfast, but not to alternate day dieting. Of course, if you’re already on a low fat diet, you may not get additional benefits from resveratrol at all.

      • Bob

        Interesting information, Phil. I recently instituted an 8-hour feeding window regimen noting your reference in the comment above (after initially hearing of the concept in the Perfect Health Diet book). It seems to be going just fine, but I would love to see some more information on the benefits, effects, etc. The effect you reference seems interesting, but previously unknown to me. Might you know of any information sources? Thanks.

      • Nevo

        When you said “if you’re already on a low fat diet, you may not get additional benefits from resveratrol at all.” What does low fat have to do with resveratrol? This is new to me.

      • guest

        I too would like to know why if you are not on a low fats diet then the resveratrol would include no benefits.

      • TheGardenAddict .

        can’t see how one would not receive benefits from resveratrol if on a low fat diet. It is true that a diet high in omega-6, transfats and hyrdrogenated fats increases inflammation and free-radical damage. Resveratrol may help to reduce some of the damage. But, people not eatting as much damaging fat can also benefit. Personally, I like to make sure I have adequate fat in my diet – minus 2 of the damaging ones that I mentioned and higher omega-3 to omega-6 ratio.

  • Coacervate

    “Use of antibacterial agents creates selective pressure for the emergence of resistant strains.” FC Tenover, …. so remove the selective pressure (i.e. use antibiotics sensibly) and the baddies revert, no more superbugs. Food science marches on.

  • BeetsBeansButts

    So interesting. Thanks Dr. Greger!

    It frustrating that the United States hasn’t taken strong leadership on this. Everyone is so afraid of Big Agribusiness.

    It would be great to see the data on organic vs conventional vs free range on more than just Beta lactamase stuff.

  • lucidvu

    Are you going to cover “superbugs” in vegetables too?

    For a real world perspective, chicken for example is usually eaten cooked – maybe not perfectly handled, but cooked nonetheless. Many contaminated vegetables on other hand are often eaten raw. Thus the actual risk of exposure to antibiotic resistant bacteria may be higher from vegetables or fruit than from meat.

    “Overall, consumption of raw vegetables represents a route of human exposure to antibiotic-resistant bacteria and resistance determinants naturally present in soil.”

    Appl Environ Microbiol. 2013 Sep;79(18):5701-9.
    doi: 10.1128/AEM.01682-13

  • TheGardenAddict .

    good reason to buy all food from farmers we know or grow our own. The organic vegetable farms are also contaminated by manure run-off from factory farms.