Tuesday, April 19, 2011

Conventional Meat May Contain MAR Bacteria: What To Do About It

7/13/11 update:  I decided that I don't want to endorse or appear to endorse the use of any meat produced by conventional methods of feeding the livestock grains, primarily corn and soybeans.  Since animals consume 80% of the grain and soy produced by U.S. agriculture, this system drives the ongoing destruction of our topsoil both through crops and through grazing.  Animal food production consumes 87% of all freshwater used in the U.S. each year, and thus is the primary driver of depletion of water reserves.  This system also produces most of the water pollution occurring in the U.S.  Our conventional livestock production system has enormous costs detailed in this article from Cornell University.  Since I have known of these costs for more than 20 years, I feel embarrassed and remorseful that I wrote this series and other articles that endorsed the use of conventional animal products.

When I wrote my guides to conventional beef (One, Two, and Three), I  looked at data reporting on residues of hormones, antibiotics, chemicals, and pesticides in conventional beef, but I did not find any information about microbial counts in meat from animals raised in conventional confined animal feeding operations (CAFOs).

Now it looks like I have to add multiple-antibiotic resistant (MAR) bacteria to the list of likely contaminants of conventional supermarket meats.   Reuters reports that researchers have found that conventional grocery meat frequently has significant levels of bacteria resistant to antibiotics. 

The Arizona-based Translational Genomics Research Institute (TGRI) tested 136 meat samples from 26 grocery stores in Illinois, Florida, California, Arizona and Washington D.C..  They found that the meat had high levels of Staphylococcus aureus (S. aureus), and more than half of the bacteria tested had resistance to multiple antibiotics.

"The study found that in 96 percent of the meats with staph bacteria the bacteria were resistant to at least one type of antibiotic, and 52 percent were resistant to three or more types. "
"Of all the types of meats where bacteria was resistant to three or more antibiotics in the study, turkey was the most resistant, followed by pork, beef and then chicken. "
While you can kill these bacteria easily by cooking the meat properly,  you also can spread these bacteria by handling the meat then other foods or objects.  You can prevent the spread of these microbes by washing hands and counters before and after handling meat and keeping other foods away from uncooked meat.

Apparently the FDA knows about this:

A spokeswoman for the Food and Drug Administration said that the agency was aware of the TGRI findings, and similar studies of antibiotic-resistant bacteria in meats, and was working with the U.S. Agriculture Department and Centers for Disease Control and Prevention on the causes and effects.

"FDA has been monitoring the situation. The TGRI study points out that the public health relevance of the findings is unclear. FDA continues to work with CDC and USDA to better understand this issue," the FDA spokeswoman said.
To give the foot-dragging bureaucrats a leg-up on this problem, I can think of two well-documented main sources for these bacteria: 1) treated (drinking) water containing multiple-antibiotic resistant (MAR) bacteria may be used to wash meat products in meat-processing facilities, and 2) confined animal feeding operations.  When you confine animals and hold large numbers in close quarters, while feeding them a grain-based, inappropriate diet, you create a breeding ground for infectious microbes. 

Simply put, we could stop directly or indirectly subsidizing pharmaceutical houses and corn-based animal feeding operations, which would save taxpayers money, reduce federal deficit spending, and make drug-laced CAFOs uneconomical compared to drug-free pasture-based operations.  This would encourage the growth of pasture-based animal operations, which when properly managed can reverse desertification and produce animal products of superior nutritional value in terms of omega-3 fatty acids, vitamins, and minerals.  The land, animals, and people will all be healthier as a result.

While the FDA et al go about taking their time "to better understanding this issue," it appears you can reduce your exposure to these microbes by implementing these strategies:

1.  If eating conventional meats, eat less turkey and pork compared to beef and chicken.  Previously I have recommended pork over chicken because pork has a better fatty acid profile than chicken (less omega-6), but now appears that pork presents a greater microbial hazard.  Hence you may want to choose chicken over pork, and remove the chicken skin to minimize omega-6 intake.
2.  Consider buying meat frozen or freezing it after purchase, because freezing can reduce microbial concentrations by up to 97-99%.
3.  Eat more whole cuts of meat and less ground meat, since ground meats may have bacteria in them whereas whole cuts will generally only have bacteria on the outside surfaces.
4. Wash your hands and counters after handling uncooked conventional meats.
5.  Cook conventional meat adequately.
6.  Whenever possible, get grain-fed meats from animals raised without antibiotics. You can get them from local farmers, butcher shops, and some 'natural' markets.  In Arizona, Sprouts Market and Sunflower Market both sell grain-fed meats from animals raised without antibiotics.  Animals raised without antibiotics very likely have lower counts of antibiotic-resistant microbes. 
7.  When economically practical, buy meat directly from farmers who raise their animals without antibiotics on pasture or species-appropriate diets.   


Rudolf said...


in your primal diet guide you say that ruminants and hindgut fermenters should be preferred, and poultry limited. Now it seems you recommend chicken before pork.

So, which one is better, if both conventionally raised?

Don said...

Hi Rudolph,

Yes, the diet guide was based only on the fatty acid profile. This new info indicates that although conventional pork has a better fatty acid profile than poultry, it may have more microbial contamination. So, if eating conventional meat, to avoid microbial contamination and excessive omega-6, the best choice could be skinless chicken breast, which provides relatively small absolute amounts of omega-6 and apparently lower levels of MAR bacteria than pork.

Anonymous said...

Hello Don. So long as you handle pork correctly and cook thoroughly, would you recommend pork over chicken? In other-words, is the dirtiness of pork to much to overcome?

Also, why is chicken recommended over turkey? I thought that chickens harbored the most bacteria? Are turkeys particularly loaded with bacteria?

Don said...


From this report, it seems you can easily make pork safe by proper handling and cooking, and it does have a little better fatty acid profile than chicken.

Apparently this study found turkey is more likely to have MAR bacteria than chicken. Like you I find that surprising, because I thought chickens got more antibiotic exposure in CAFOs.

Again, thorough freezing, cooking, and proper handling can keep your final prepared meat safe, regardless of type. The disturbing issue is that supermarket meat now acts as a vector for widespread distribution of MAR bacteria into the community.

Caveman Productions said...

Just another reason I only trust grass fed beef for eating raw or very rare.I had heard that freezing is a good way to kill bateria, and that's what I usually do before eating raw, but it's good to hear it from another source. thanks for sharing.

Anonymous said...

Is conventional grain fed meat unsafe to eat raw after it has been frozen? I have done this in the past with a lemon juice olive oil vinegrette and been fine, but don't want to chance it.

Don said...


I don't recommend eating conventional beef raw even if previously frozen.

Stan (Heretic) said...


I agree, that's why we buy local meat and fat (pork belies) whenever we can.

Re: Simply put, we could stop directly or indirectly subsidizing pharmaceutical houses and corn-based animal feeding operations,...

This will probably happen by itself when the Northern American economy crashes and people will go back to economic basics and basic survival. No subsidies will be possible if politicians of the "Quantitative Easing" and bank bailout culture will go away.