Recently, the Seattle Post-Intelligencer reported that traces of Methicillin-Resistant Staphylococcus aurerus, the bacteria commonly known as MRSA, are present on swine farms in the Midwest, prompting some members of Congress and public health advocates to call for an investigation of our food supply for the presence of the bacteria. While we here at Keep Our Food Safe are strong advocates of vigilance when it comes to protecting our nation’s food supply, this reaction may be a little too premature.  Let me explain.

Staphylococcus aurerus is a bacteria found in many forms; sometimes it can cause an infection, but not always.  In fact, about one-third of the people in this country are colonized with the staph bacteria.  But don’t worry, that just means the bacteria is present on their body somewhere, not necessarily causing an infection.  Staph bacteria is the most common cause of minor skin infections, like pimples and boils, and is usually treated with antibiotics.  But staph infections can also be responsible for more serious illnesses, like pneumonia, which is why it’s so important to practice good hygiene to minimize the chance of the bacteria spreading.

Human strains of MRSA are some of the more deadly types of staph infections.  What puts the MR in MRSA is the fact that this strain is resistant to the antibiotic methicillin, making infection difficult to treat.  The Centers for Disease Control and Prevention estimates about 1.5 percent of the U.S. population is colonized with MRSA.

For a long time, health officials thought MRSA was only present in people, but evidence of colonization has been found in our dogs, cats, horses and pigs.  Additionally, a report surfaced indicating the bacteria was present in pork in the Netherlands and Canada.  Since the United States imports more than 760 million pounds of Canadian pork, Dr. Tara Smith, an epidemiologist from the University of Iowa College of Public Health, was prompted to conduct a series of tests on swine farms in Iowa and Illinois. Dr. Smith’s report indicated nearly 70 percent of the pigs and more than 60 percent of workers tested positive for a MRSA colonization.

But before you fill up your garbage can with all the pork in your freezer, it’s important to think about a few things.  The sample size Dr. Smith used to conduct her study was incredibly small – 299 pigs and only 20 employees – and what she found was a unique strain of MRSA unrelated to the strains causing human illness.  In addition, MRSA colonization was present on only one of the farms.

Dr. Smith suggested in her report that there might be a link between the use of antibiotics and the presence of MRSA in the swine, and that perhaps the use resulted in an increased incidence of MRSA in the animals. She makes a good point, but if this particular MRSA isn’t causing the animals to get sick and it’s not causing humans to get sick, we should probably make sure that the use of those antibiotics is actually a bad thing before we go jumping to conclusions.

Antibiotics can be a good thing.  They really don’t stay in the animal’s system long enough that you’d be consuming antibiotics.  Plus antibiotics keep both animals and people healthy, and without them, more diseases can spread. The American Veterinary Medical Association agrees. 

Bottom line?   Colonization means the bacteria is present, not that infection is present.  And while it may be worthwhile to test livestock and workers to minimize occupational hazards, most public health officials and food animal veterinarians agree MRSA transmission is not a problem in our food supply.  So as always, practice good hygiene and cook your meat according to the directions or to suggestions by the U.S. Department of Agriculture.   As for that ham sandwich?  Go ahead and enjoy.