by Marion Nestle
Apr 10 2009

Is free-range pork more contaminated than industrial pork?

My e-mail inbox is flooded with copies of an op-ed from today’s New York Times arguing that pigs running around outside have “higher rates” of Salmonella, toxoplasma, and, most alarming, trichina than pigs raised in factory farms. The writer,  James McWilliams, is a prize-winning historian at Texas State San Marcos whose forthcoming book is about the dangers of the locavore movement to the future of food.

I put “higher rates” in quotation marks because that is not what the study measured.  The study on which McWilliams based his op-ed is published in Foodborne Pathogens and Disease. The investigators actually measured “seropositivity” (antibodies) in the pigs’ blood.  But the presence of antibodies does not necessarily mean that the animals – or their meat – are infected.  It means that the free-range pigs were exposed to the organisms at some point and developed immunity to them.  The industrial pigs were not exposed and did not develop immunity to these microorganisms.  But you would never know that from reading the op-ed.   How come?

Guess who paid for the study?  The National Pork Board, of course.

The Center for a Livable Future at Johns Hopkins has much to say about all this.  My point, as always, is that sponsored studies are invariably designed in ways that produce results favorable to the sponsor.    In this case, the sponsor represents industrial pork producers.

April 14 update:  the editors of the New York Times have added a note to the electronic version of Professor McWilliams’ op-ed pointing out the National Pork Board sponsorship of the study on which he based his piece.  And McWilliams rebuts arguments against his piece on the Atlantic Food Channel, while conceding that he may have gotten the science wrong.

  • Rob Smart

    Thank you for getting to the “dark” bottom of yet another attempt by large entrenched interests to manage the dialog (and protect their monied interests).

    Given recent revelations about pork, antibiotics, etc., it should not be a surprise to anyone that this is happening.

    We just all need to move beyond the “fear, uncertainty and doubt” (thanks Tom Laskawy) and focus on common sense.


    Rob Smart
    (aka “Jambutter” on Twitter)

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  • Jon

    Just another example of the masochistic meat industry. These are the same people who opposed organic certification for meat, even though organic certification can only boost sales. (It would be really ironic if vegan raw-food diets were the sock puppet of the meat industry.)

  • Michelle @ Find Your Balance

    Haha, it’s really too predictable, isn’t it?

  • John Serrao

    Nice catch.

  • Viv

    Thank you! Although that Op-Ed was not going to turn me against free range, pastured pork (we have lovely options here in Seattle) it is reassuring to have all the facts.

    It makes today’s Mangalitsa pork purchase (shoulder for braising, lard for cooking and baking and neck bones for stock making, from Heath Putnam of Wooly Pigs) all the more delicious.

    I’m counting the hours to tomorrow’s very porky and healthy supper.

    Oink oink. :)

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  • D. Warner

    “… sponsored studies are invariably designed in ways that produce results favorable to the sponsor.” Sort of like, say, the anti-meat Center for a Livable Future issuing a report that (shock) finds “industrial farms” — whatever those are — the root of all society’s evils.

    The real truth is that every production system has pluses and minuses. It does seem logical, however, that biosecure hog barns would better protect pigs from pathogens and diseases.

    And as for “organic,” it doesn’t mean safe.

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