Antibiotic resistance in food animals: What's wrong with this report?

There have been many reports lately in the major entertainment-news media regarding the use of antibiotics in food animals. In only the last two weeks nearly every segment of the so-called major media – television, print, radio and internet – reported on a study purporting to show that nearly all meat products sampled in grocery stores were contaminated by antibiotic resistant strains of bacteria. What the entertainment-news media failed to report, however, were the bulk of the actual findings of the study, funded by the Pew Charitable Trust, and the study’s very significant shortcomings.

Firstly, the Pew Commission on Industrial Farm Animal Production (PCIFAP) was formed in 2006 to “…investigate the problems associated with industrial farm animal production…and to solve them.” Think about that for a moment. Though in its mission statement PCIFAP says it was “…formed to conduct a comprehensive, fact-based and balanced examination of key aspects of the farm animal industry,” the group’s beginning assumption is that there are “problems” with animal agriculture and they are going to “solve” them. With a brief like that, it’s naïve in the extreme to expect findings which are comprehensive, fact-based, or balanced.

Little wonder that in the preface of their 2008 report on US agriculture, PCIFAP calls modern US agriculture “the agro-industrial complex” and equates it with President Eisenhower’s dire warnings about the dangers of the military-industrial complex. If you've followed histrory at all, you might have noted that the military-industrial complex did not, in fact, take over and destroy the world.

The preface of the PCIFAP report closes with this paragraph: “The present system of producing food animals in the United States is not sustainable and presents an unacceptable level of risk to public health and damage to the environment, as well as unnecessary harm to the animals we raise for food.” To see a copy of the report, visit http://www.ncifap.org/bin/e/j/PCIFAPFin.pdf

It’s clear that Pew and their affiliate researchers have taken a one-sided, highly-partisan approach to studying US agriculture. Let’s look at some of the shortcomings of their latest so-called study.

Pew used the Translational Genomics Research Institute (TGen) of Flagstaff, Ariz. to conduct their study. TGen collected 136 samples of meat and poultry from 80 brands in 26 grocery stores in five US cities – Los Angeles, Flagstaff, Ft. Lauderdale, Chicago, and Washington D.C. The company refused to disclose the brand names or the names of the grocery stores. Those who’ve studied statistics and scientific methodology will recognize that 136 is a tiny sample size; far too small a size from which to draw their sweeping conclusion that bacterial contamination of the US meat and poultry supply is “pervasive and widespread.”

When the USDA studies bacteria in the US meat supply, they take thousands of samples from grocery stores across the country, and their report includes store and brand names. The USDA also samples over long periods of time, a strategy which helps to identify trends in contamination. The USDA, in fact, is continuously sampling all food products available to US consumers – not just meat and poultry.

TGen reported that 47 percent (“nearly half”) of the samples they collected were contaminated with Staphylococcus aureus, and that 52 percent of those bacteria were resistant to at least three classes of antibiotics. Furthermore, TGen said that DNA testing indicated food animals “as the major source” of the contamination.

Unfortunately, TGen seems to have been fibbing about the source of the contamination. According to Drs. Elizabeth Wagstrom and Peter Davies of the University of Minnesota College of Veterinary Population Medicine, isolates of Methicillin-resistant S. aureus (MRSA) found in the study were human types, meaning the meat likely was contaminated by people. Methicillin, they added, is not used in food animals.

Moreover, according to Dr. Ellin Doyle of the University of Wisconsin's Food Research Institute, Staphylococcus aureus is found in over half of human nasal passages. The incidence of MRSA is much lower – estimates by the Centers for Disease Control (CDC) indicate that only about 1.5 percent of people in the general population carry MRSA. Doyle adds that only two foodborne outbreaks of MRSA have been identified, and both were attributed to food handlers contaminating food – not to the food source itself. S. aureus is also carried by household pets and can be transmitted in health care settings, she said.

The TGen study also failed to sample foodstuffs from non-meat and poultry areas of the grocery stores. Such samples would have provided a “control” of sorts, and provided the researchers data which would likely have helped them understand whether humans or food animals were responsible for the contamination. Were S. aureus and/or MRSA found on canned goods, bakery products, or fruits and vegetables, for instance, the researchers could hardly have concluded that the contamination came from food animals. The culprit would have been identified as most likely human.

Unfortunately, consumers can’t rely on the major entertainment-news media for honest reporting. To arm themselves with the facts, consumers should view most news reporting through a skeptical filter, asking themselves whether what they are being told is fact-based and reasonable or speculation-based and sensational.

In the next installment of this series we’ll look a what pathogenic bacteria are and how they make us sick.