Pork Safety: Free-Range Versus Factory-Farmed

A Pork Safety Study Taken to Task

They're cute. But, are they disease free?

They're cute. But, are they disease free?

James McWilliams, an Op-Ed contributor to the New York Times, wrote about a recent study published in the journal Foodborne Pathogens and Disease that seemed to dispute the commonly held opinion that free-range pork is safer to eat than factory-farmed pigs.

The authors studied the prevalence of trichinella, toxoplasma, and salmonella antibodies in pigs raised either free-range or factory farmed.  Entited “Seroprevalence of Trichinella, Toxoplasma, and Salmonella in Antimicrobial-Free and Conventional Swine Production Systems”, the study found that pigs who lived their lives outdoors had a higher incidence of ’seropositivity’ (link). According to an online medical dictionary, this means that there were “antibodies or other immune markers in [their] serum, that indicate prior exposure to a particular organism or antigen”.

Marion Nestle, always quick to the common sense argument, indicates that, “…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” (link). The authors do not discuss the implications of seropositivity and what it means in terms of consumer safety.

They do, however, imply that the presence of antibodies is a definite negative, and that it is evidence of the “risk” pigs and their owners are taking by living outside. The study “warrants a robust epidemiologic study to determine the role of various risk factors in the two production systems that may lead to persistence of bacterial (Salmonella) pathogens and reemergence of parasites (such as Trichinella) of historical significance”.

Is being exposed to the spectrum of pathogens in nature really a bad thing? Moms who host chicken pox parties for the neighborhood kids may disagree. Clearly, the better test for whether or not free-range versus confined pork production is healthier is to look at the concurrent disease incident rates for humans. Hence, the question should be on which pork diet is a person more likely to become sick?

Marion Nestle also suggests that the authors committed this grand sin of omission because the study was paid for by National Pork Board. Although the author of the op-ed piece is probably not on the their payroll, the paper’s authors who were paid appear to intentionally mislead the readers of their study. It is highly suspect that scientists would forget that correlation does not equal causation. But, there in the paper’s introduction is the implication that the decline in trichinellosis cases during 1997-2001 is due to the prevalence of factory farming (which, it should be pointed out, has around for decades).

This study reveals why it is so important to have independent funding. There is less chance of the scientists altering the tone of their work in order to please organizations like the National Pork Board. It also speaks to the importance of having a scientifically literate population. Knowing what the term “seropositivity” means or the willingness to look it up, at least, diminishes the ability for biased scientists and op-ed writers to use scare tactics.

Foremost, though, this episode demonstrates how trenchant Peter Sagal’s characterization of Michael Pollan’s work was. Peter Sagal, from Wait Wait Don’t Tell Me, opined that, “one of the reasons I like your work is because I love conspiracy theories. It’s a hobby of mine. And, you are like this conspiracy theorist, except there really is a conspiracy”.  Indeed, sometimes, it really does feel like we are living in a world of “Smoked ‘Bacon’ and Mirrors“.

UPDATE:

Parke Wilde, at the US Food Policy blog, cashed in a favor and personally asked the author of the op-ed piece, James McWilliams, to explain the controvery caused by his, well, controversial article.   First, James McWilliams contends that he is against industrial meat production and in no way did the National Pork Board alert him to the study.  So, why didn’t he mention the funding source of the study?

“That’s a tough question,” he responded.

“My fear was that mentioning the funding source would have immediately led a substantial portion of readers to quit reading. Given that my goal in covering these controversial issues is to make sure that we in the sustainable food movement remain vigilant about the alternatives we have chosen, the last thing I wanted was to alienate readers who would automatically (and perhaps mistakenly) assume that the industry backing undermined the results of the study. If there was a precedent of journalists consistently citing funding sources, then perhaps I would say yes, I should have done it. My choice was to trust the journal’s peer review process and not mention the funding source. Maybe I should have noted that the journal is highly respected and peer reviewed.”

Had this been an article by an acreditted reporter or journalist, I would take his point to task.  It is not the journalist’s job to downplay the conterversial aspect of a piece , but to  point towards the truth.  Usually that means objectively presenting all relevant information.  Thankfully, as McWilliams points out, reporters do consistently site funding sources.  The lesson learned?  Take op-ed pieces with a grain of salt or perhaps some investigative work of your own.

April 13, 2009  Tags: , , ,   Posted in: Health, Science & Technology

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