As I wrote a year ago in a blog post, "Grass-Fed vs Grain-Fed Beef and the Holy Grail: A Literature Review," several people have commented that switching from grain to grass feeding could be one of the solutions to the problem with foodborne pathogens in cattle and other livestock. Quotes like these are becoming more common on the Internet and in recent media reports:

“Products from grass-fed animals are safer than food from conventionally-raised animals.” Eatwild, 2008.

“Research has shown that the strains of E. coli most devastating to humans are the product of feedlots, not cows. This is due to the animals being forced to eat an unnatural diet, and not their natural choice, grass.” Grass-Fed Beef: Safer and Healthier, Animal Welfare Approved, June 15, 2008.

I did an extensive literature review and simply did not find support for the belief that switching from grain to grass for cattle feed would make the world a bad place to be pathogenic E. coli. Now comes an article by S. Reinstein, J.T. Fox, X. Shi, M.J. Alam, D.G. Renter and T.G. Nagaraja. 2009, “Prevalence of Escherichia coli O157:H7 in organically and naturally raised beef cattle. Applied & Environmental Microbiology 75(16):5421-5423,” which states:

"The prevalences of E. coli O157:H7 that we observed in organically and naturally raised beef cattle were similar to the previously reported prevalence in conventionally raised cattle," the researchers said. "No major differences in antibiotic susceptibility patterns among the isolates were observed."

Now, before the internet erupts into a belief culture war between grain feeders and grass feeders, I am not saying that the cows themselves may not well be better off eating grass and roaming the range, and I am not saying that feedlots miles wide are not environmental hazards, but I think we need to face the fact that grain vs grass does not mean “E. coli.”

  • mph

    I don’t have access to the full text of the article, but the abstract does not say anything about grass-vs-grain, only organic-vs-conventional. My understanding is that organic beef can be fed grain. Can you clarify what the article actually says regarding feed types?

  • Joe

    The study you cite looked at organically and naturally raised beef cattle. Neither of these labels guarantee or even imply grassfed. Both organic and “natural” beef can and often are fed grain and are usually raised in feedlots just like conventional beef cattle. The only difference between these labels and conventional beef being the exclusion of antibiotics and synthetic growth hormones. Are there other studies you did not cite in your post that did specifically look at grassfed vs. grain fed? True grassfed beef is NEVER fed grain and is grown on it’s mother’s milk, and grain free forage.

  • You might find these references usefull these are Grass Fed not organic comparisons. Sadly not all organic is grass fed, but all grass fed Animals in the AWA and the AGA program are grass fed we physicaly Audit to check exactly that fact and many others. We really are a science based program with the evidence to back the claims we make. I appreciate your effort to balance the debate, and our team would be more than happy to assist if you need further research material. The facts are the facts, acid balance in rumen content has an impact on E Coli no real dispute exsists. There is always, I am sure there is a chance that the Grass fed beef could be contaminated by contact with grain fed Ecoli which is why our producers choose carefully who processes their animals.
    Always here to help Consumers and Humane Family Farmers learn the truth.
    Program Director.
    No Ecoli 157, * Russell, J.B., F. Diez-Gonzalez, and G.N. Jarvis, “Potential Effect on Cattle Diets and the Transmission of Pathogenic Escherichia Coli to Humans” Microbes Infect 2, no, 1 (2000) 45-53.
    **  Bailey, G.D., B.A. Vantelow et al. (2003) “A study of the food borne pathogens Campylobacter, Listeria and Yersinia, in faeces from slaughter-age cattle and sheep in Australia.” Commun Dis Intell 27)2): 249-57.

  • Ken

    Unless I missed something in botany almost all grass and certainly what’s used to raising cattle contains grain after all grain is just grass seeds and it’s used because it contains more calories per pound than the stalks and leaves.

  • hands off

    All grains are not created equal and the grains fed to “conventionally raised”, feed lotted cattle is unnatural and does promote e. coli, as does the unnatural process of penning to insure the extra fat and poundage, not to mention exposure to increased amounts of fecal matter, much of which finds its way back into the cattle penned, and the admittedly unsanitary slaughtering process. Grass fed is better and safer, especially when not “finished” with corn or grain, and especially when smaller, and more sanitary facilities are used to process. I know a small grass fed operation here in Colorado from whom I purchase my beef. I have not, in 5 yrs, gotten sick from this beef, and it tastes so much better than any beef I have ever eaten and is low in saturated fat and high in omega 3’s, facts that are not true of conventional, grainfed, natural or organic beef, unless in the case of natural or organic, they are also only grassfed.

  • Bill-
    You know as well as I that ‘organic’ or ‘natural’ beef can be feedlotted and fed grains. So why misinform us with this study that did NOT look at grass-only diet versus grain?

  • I found the article off my university library online catalog. Again, the study did not look at 100% grassfed beef (from start to finish). The study incorrectly states that organic and naturally raised beef are “either required to graze on pasture or fed a forage-based diet”. That statement is actually incorrect. In both of those systems grain can be fed and the cattle can be feedlotted for finishing. Because of that, this study says nothing about 100% grassfed cattle versus conventional. That was not their sample population, therefore you can’t make that inference.

  • Bix

    This is a great opportunity to bring up your lit review about grass-fed, which to me was eye-opening. (I guess we can add organically- and naturally-raised beef to it.)
    Some points:
    A definition:
    “The USDA Agricultural Marketing Service issued a voluntary standard for grass (forage) fed marketing claims last year that states: √¢‚Ǩ≈ìgrass fed standard states that grass and/or forage shall be the feed source consumed for the lifetime of the ruminant animal, with the exception of milk consumed prior to weaning. The diet shall be derived solely from forage and animals cannot be fed grain or grain by-products and must have continuous access to pasture during the growing season.√¢‚ǨÔøΩ
    “E. coli O157:H7, Campylobacter, Salmonella, and other dangerous pathogens have been repeatedly isolated from both grass and grain fed livestock.”
    “Studies by other researchers worldwide have since found little difference in acid resistant E. coli O157:H7 among grain- verses grass-fed cattle, and some even found more E. coli O157:H7 shed by grass-fed animals.”
    “Outbreaks have been traced back to grass-fed and pastured animals, as well as animals in feedlots. Notably, the E. coli O157:H7 spinach outbreak strain in 2006 was isolated from grass-fed cattle.”
    “Another outbreak of E. coli O157:H7 was linked recently to raw milk and colostrum from cattle raised organically on grass.”
    And this one, which really changed my mind:
    “It has been discovered that E. coli O157:H7 and Salmonella can rapidly switch from being √¢‚Ǩ≈ìacid sensitive√¢‚ǨÔøΩ to √¢‚Ǩ≈ìacid resistant√¢‚ǨÔøΩ within minutes after entering an acidic environment (such as the human stomach). Thus, even if the grass-fed/E. coli acid-resistance hypothesis were true, manipulating the diet may not have any effect since pathogens can adapt quickly to new environments like the human stomach.”
    That was a great review.

  • jay

    Russel, James B. Rumen Microbiology and Its Role in Ruminant Nutrition. (Ithaca, NY: self published, 2002.)