Conventional Ground Beef Is Three Times More Likely to Contain Antibiotic-Resistant Fecal Bacteria Than Grass-Fed Beef

Story at-a-glance

  • Factory farming of beef is efficient and cost-effective, but comes with a number of serious side effects that can threaten your health, including contamination with antibiotic-resistant superbugs
  • Testing revealed 100 percent of all ground beef samples contained bacteria associated with fecal contamination, which can cause blood- or urinary tract infections, some which can be life threatening
  • 18 percent of conventional ground beef samples were contaminated with antibiotic-resistant bacteria, compared to nine percent of sustainably raised beef, and only six percent of grass-fed beef


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

Factory farming methods produce a number of side effects that can threaten your health and even your life. Contamination with disease-causing fecal bacteria is one of them.

To combat foodborne illness, the food industry has created solutions that further worsen matters — sterilization methods such as high heat, chemicals (chlorine-based or lactic acid washes, for example), and/or radiation are all common industry attempts to "sterilize" your food before it reaches the store.

Yet the central issue remains unaddressed, which is the lack of hygiene standards in the raising, slaughtering, and processing of the animals.

A large percentage of meat products become contaminated when the animals' intestines are punctured and stool spills onto the meat being processed.

This is the real problem — not undercooking, as properly processed healthy meat will not harm you if it's undercooked because it will not be contaminated with fecal bacteria.

In 2011, researchers found about half of all meats and poultry sold in grocery stores were contaminated with drug-resistant Staphylococcus aureus, the bacteria that causes most staph infections.

Now, a new Consumer Report study1,2,3,4,5 warns ALL store-bought ground beef contains fecal bacteria, and factory farmed beef often contains dangerous antibiotic-resistant bacteria as well.

Ground Beef Accounts for Most E. Coli Outbreaks

As reported by Consumer Reports:

"Just before the July 4 holiday this year, 13.5 tons of ground beef and steak destined for restaurants and other food-service operations were recalled on a single day because of possible contamination with... E. coli O157:H7.

That particular bacterial strain can release a toxin that damages the lining of the intestine, often leading to abdominal cramps, bloody diarrhea, vomiting, and in some cases, life-threatening kidney damage...

Between 2003 and 2012, there were almost 80 outbreaks of E. coli O157 due to tainted beef, sickening 1,144 people, putting 316 in the hospital, and killing five. Ground beef was the source of the majority of those outbreaks."

According to Centers for Disease Control and Prevention (CDC) epidemiologist Hannah Gould, food poisoning is vastly underreported. The CDC estimates that for every reported case of E. coli O157, another 26 incidences go unreported.

Beef is also a common cause of salmonella outbreaks.

Why Ground Beef Is So Unsafe

Ground beef tends to be far more problematic than solid cuts of meat, and the reason for this is that in the latter the bacteria tend to remain on the surface of the meat. Once you cook it, most of the bacteria are destroyed.

When the meat is ground, however, those same bacteria get mixed throughout the meat, contaminating all of it. So if you like your hamburger on the rare side, the pathogens may still be alive and well in the center of the beef patty.

Another contributing factor is the fact that in the making of ground beef, meat from a number of animals is mixed together, and all you need is for one contaminated animal to affect a very large batch of meat.

Moreover, as noted by the featured article:

"Ground beef (like other ground meats) can also go through several grinding steps at processing plants and in stores, providing more opportunities for cross-contamination to occur. And then there's the way home cooks handle raw ground beef: kneading it with bare hands to form burger patties or a meatloaf.

Unless you're scrupulous about washing your hands thoroughly afterward, bacteria can remain and contaminate everything you touch — from the surfaces in your kitchen to other foods you are preparing."

CAFO Ground Beef versus Organic Ground Beef

Consumer Reports purchased 300 packages (totaling 458 pounds) of ground beef from 103 stores in 26 cities across the US. As reported in the featured article:

"We bought all types of ground beef: conventional — the most common type of beef sold... [and] beef that was raised in more sustainable ways, which have important implications for food safety and animal welfare.

At a minimum, sustainably produced beef was raised without antibiotics.

Even better are organic and grass-fed methods. Organic cattle are not given antibiotics or other drugs, and they are fed organic feed. Grass-fed cattle usually don't get antibiotics, and they spend their lives on pasture, not feedlots."

The beef samples (181 conventionally raised, 116 more sustainably produced, including organic grass-fed) were then analyzed for the presence of five types of disease-causing bacteria:

  • Clostridium perfringens
  • E. coli (including O157 and six other toxin-producing strains)
  • Enterococcus
  • Salmonella
  • Staphylococcus aureus

The samples were also put through secondary testing to ascertain whether the bacteria were resistant to antibiotics used in human medicine. Their results showed that:

  • 100 percent of all ground beef samples contained bacteria associated with fecal contamination (enterococcus and/or nontoxin-producing E. coli). In humans, these bacteria can cause blood or urinary tract infections
  • Nearly 20 percent contained Clostridium perfringens, a bacteria responsible for an estimated one million cases of food poisoning each year in the US
  • 10 percent contained a toxin-producing strain of Staphylococcus aureus, which cannot be destroyed even with thorough cooking  
  • One percent contained salmonella, which is responsible for an estimated 1.2 million illnesses and 450 deaths in the US each year
  • Three of the conventional samples had methicillin-resistant Staphylococcus aureus (MRSA), which kills nearly 19,000 people each year.6, 7 None of the sustainably raised beef samples contained MRSA

Organically Raised Beef Is Safer; Grass-Fed Is Best

Overall, beef from animals raised in confined animal feeding operations (CAFOs) was more likely to be contaminated with bacteria, including antibiotic-resistant bacteria, compared to beef from sustainably raised animals. According to Consumer Reports:

"... 18 percent of conventional beef samples were contaminated with superbugs — the dangerous bacteria that are resistant to three or more classes of antibiotics — compared with just nine percent of beef from samples that were sustainably produced... But the biggest difference we found was between conventional and grass-fed beef. Just six percent of [grass-fed] samples contained superbugs...

'We know that sustainable methods are better for the environment and more humane to animals. But our tests also show that these methods can produce ground beef that poses fewer public health risks... We suggest that you choose what's labeled 'grass-fed organic beef' whenever you can,' Rangan says."

Urvashi Rangan, executive director of the Center for Food Safety and Sustainability at Consumer Reports also noted that:8

"This study is significant, because it's among the largest scientific studies to show that sustainable methods of raising cattle can produce cleaner and safer ground beef."

You Eat What Your Food Ate...

The Beef Report points out several of the factors that contribute to making CAFO beef unsafe. Many of the problems are rooted in the animals' unnatural diet, which include:

Grain-based feed, which the cows cannot properly digest, leading to increased shedding of pathogens such as E.coli in their feces Industrial food waste Artificial ingredients, such as plastic pellets that serve as a grass fiber substitute
Animal waste, such as slaughter byproducts, cattle blood and blood meal, dried manure, and chicken litter Antibiotics, veterinary drugs, and growth hormones Pesticides and insecticides, added either to the feed or administered via ear tags, to control pests such as horn flies

The use of animal byproducts is particularly disconcerting, as they can transmit infectious proteins called prions, thereby spreading bovine spongiform encephalopathy (BSE, aka Mad Cow Disease) among the cattle. What's worse, these prions may also infect humans who eat tainted meat, causing the human version of Mad Cow, known as Creutzfeldt-Jakob Disease, which is incurable.

Some researchers have even suggested these prions may contribute to the development of Alzheimer's disease. The report notes that this grain-based diet has environmental ramifications too. It takes seven kilograms of grain to produce one kilogram of beef, so the conventional beef industry uses vast amounts of corn and soybeans. These two feed crops in turn require:

  • Significant amounts of water. It takes 1,000 tons of water to grow one ton of grain feed
  • Synthetic fertilizers, the manufacturing of which is a major contributor to greenhouse gas emissions. Synthetic fertilizers also destroy organic matter in the soil; contaminate waterways; harm wildlife; and create environmental "dead zones"
  • Toxic pesticides, which contaminate air, soil, and water, and pose health risks to farm workers, rural residents, wildlife, and pollinating insects

The vast majority of corn and soy grown in the US is also genetically engineered (GE) to be resistant to pesticides, which has led to a dramatic increase in pesticide use. Most GE corn and soy is resistant to glyphosate, which has been classified as "probably carcinogenic" to humans. As noted by Consumer Reports:

"The application of agents such as glyphosate and other pesticides in growing these crops is not a sustainable solution for killing weeds and insects."

Grass-Fed BeefI Is Also Nutritionally Superior

Feeding animals a species-appropriate diet (which for cows means grazing on grass) profoundly improves the nutritional quality of their meat, which has been established by science. It also virtually eliminates toxins such as glyphosate and other pesticides, which is the other side of the healthy-diet equation. In 2009, a joint research project between the US Department of Agriculture (USDA) and Clemson University determined the numerous ways grass-fed beef beats grain-fed beef for your health. In a side-by-side comparison, they determined that grass-fed beef was superior in the following ways:9

Higher in total omega-3s Higher in the B-vitamins thiamin and riboflavin
A healthier ratio of omega-6 to omega-3 fatty acids (1.65 vs. 4.84) Higher in the minerals calcium, magnesium, and potassium
Higher in CLA (cis-9 trans-11), a potential cancer fighter Higher in vitamin E (alpha-tocopherol)
Higher in vaccenic acid (which can be transformed into CLA) Higher in beta-carotene

Five Ways CAFOs Destroy the Environment

Consumer Reports also addresses the ways in which CAFOs affect the environment, noting that these environmental costs are not included when calculating costs of conventional beef production. The meat may be inexpensive, but consumers still pay for these externalized costs, including higher health care costs associated with antibiotic-resistant disease, and the cleanup of pollution originating from factory farms. Green Planet has also published an excellent article10 summarizing five basic ways industrialized farming contributes to environmental destruction:

  • Air pollution: Industrial agriculture is responsible for more than 37 percent of methane emissions, 90 percent of CO2, and copious hydrogen sulfide ammonia. Methane has a global warming potential 20 times higher than carbon dioxide.
  • Water pollution: Industrial agriculture uses up to 70 percent of the world's fresh water supply. The Environmental Protection Agency (EPA) estimates 75 percent of all water-quality problems in America's rivers and streams is from chemical-laden agricultural run-off that leads to toxic algal blooms, fish kills, and "dead zones."
  • Deforestation: In the US alone, more than 260 million acres of native forests have been cleared to make room for crop fields, most of which are used exclusively to grow livestock feed (corn and soy). Deforestation is responsible for 2.4 billion tons of CO2 release annually.
  • Soils: Nature abhors monoculture, as monoculture leads to soil depletion, erosion, depletion of the water table, loss of soil nutrients, and the application of massive quantities of synthetic agricultural chemicals.
  • Carbon emissions: CAFOs use about 5.5 gallons of fossil fuels per acre (presumably per year, as article did not specify), between transportation, application of chemicals, and the incredible amount of energy it takes to run these massive productions. The average farm in the US spans 418 acres, meaning it will guzzle about 2,300 gallons of fossil fuels. By adopting a circular economy (reusing and recycling), carbon emissions could be cut by nearly 70 percent by 2030.

Understanding Beef Labels

Organic, biodynamic farms tend to be much smaller and cleaner, since the animals are not crammed together in massive cramped feedlots. As a result, the animals are far less likely to harbor dangerous pathogens that contaminate the meat. Grass-fed cattle are also raised on their natural food supply: grass, which improves the health of the cattle and, subsequently, the meat. Besides that, there are numerous environmental reasons for supporting organic, grass-fed cattle ranching rather than buying conventional corn-raised beef.

Fortunately, grass-fed beef, pastured poultry, and organic pastured eggs and dairy are becoming easier to find. Larger grocery chains are jumping on the "organic band wagon," but purchasing from your local organic farmers and ranchers is still preferred. That said, when shopping for beef, keep the following labels in mind to help you find high-quality products.11 Remember, as suggested by Consumer Reports, your safest alternative is both organic and grass-fed.

100% USDA Organic label offers excellent assurance that antibiotics have not been used at any stage of production.
"No antibiotics administered" and similar labels also offer high assurance that antibiotics have not been used, especially if accompanied by a "USDA process Verified" shield.
"Grass-fed" label coupled with USDA Organic label means no antibiotics have been used, but if the "grass-fed" label appears alone, antibiotics may have been given.
"American Grass-fed" and "Food Alliance Grass-fed" labels indicate that in addition to having been raised on grass, the animal in question received no antibiotics. This is the best label of all but is in the early stages of development so you will likely not see it widely until next year.
The following three labels: "Antibiotic-free," "No antibiotic residues," and "No antibiotic growth promotants," have not been approved by the USDA and may be misleading if not outright fraudulent.
"Natural" or "All-Natural" is completely meaningless and has no bearing on whether or not the animal was raised according to organic principles. "Natural" meat and poultry products can by law receive antibiotics, hormones, and genetically engineered grains, and can be raised in CAFOs.


By continuing to browse our site you agree to our use of cookies, revised Privacy Policy and Terms of Service.