A Consumer Reports investigation analyzed 300 samples of ground beef bought from food stores in the US, reporting 100% of the products tested positive for bacteria found in feces. The beef samples where categorized as either ‘conventional’ or ‘more sustainably produced’, with the latter category comprising cattle raised without the use of antibiotics, including cows with a grass-only diet and those raised on organic farms. Consumer Reports found higher levels of some bacteria in conventionally raised cattle and recommended consumers should buy beef from cattle raised without antibiotics, on food safety grounds.
Dr. Francisco Diez-Gonzalez, Professor of Food Safety Microbiology, University of Minnesota (webpage):
Expertise: Pre-harvest ecology of foodborne pathogens; Safety of organic foods; Safety of dairy foods.
“Fecal bacteria like non-pathogenic E. coli and Enterococcus by themselves do not represent a significant health risk for the consumer. Only a small fraction of those organisms may actually be potentially pathogenic. Typically these indicator bacteria are used to assess the quality and conditions of handling of meat and in some instances they may actually correlate with the presence of pathogens. However, to this date none of them are good predictors of the presence of E. coli O157:H7 and Salmonella.
“The explanation for generic E. coli present in larger numbers in the conventionally raised beef appears to be due to the several studies that have reported that the counts of this bacterial species is consistently higher in the feces of animals that are fed diets based on starchy materials such as corn, in comparison to forage-based diets. For other bacterial groups, the diet effect is not as consistent as with E. coli.
“There have been several studies in the past that have compared the presence of antibiotic resistant bacteria in organic vs. conventional livestock and poultry. Some of these studies have reported similar trends as this CR report and some of them have found little or no difference. However, this report should be subjected to the rigor of scientific peer-review before it is included as part of the literature that have looked into this issue. Once a consistent trend is found in a critical number of studies then we could take these findings as a guide for the kind of recommendations that the authors are making.”
Dr. Jeffrey LeJeune, Professor and Head of the Food Animal Health Research Program, Ohio State University (webpage):
Expertise: Pre-slaughter control of human foodborne pathogens and antimicrobial resistant bacteria in the animal host and the environment.
“Many raw foods will occasionally contain E. coli and coliforms (bacteria found in feces and the environment). However, muscle tissue itself in live animals generally has very little bacterial contamination. Most animals will likely have E.coli in their intestines and on their hide at the time of slaughter and much of the contamination of the beef occurs from the outside of the animal at the time of slaughter and processing. Thus, it is important to realize that slaughter hygiene, not livestock management practices, are probably one of the biggest factors affecting the microbial loads in ground beef.
“Pathogens and antibiotic resistant bacteria are a slightly different story: their presence in raw meat reflects the numbers and prevalence of bacteria that enter the slaughterhouse colonized in the live animals, and this report has several interesting observations regarding differences between meat categorized as ‘conventional’ or ‘more sustainably produced’. Several similar studies have been previously conducted, and one group (Young et al, 2009) put all the studies together, comparing pathogens and antibiotic resistance isolated from animals raised conventionally and organically, to see what the ‘average’ result was. They were unable to identify any consistent trends for beef.
“Clearly, there are many questions we don’t know the answers to about what exactly makes some cows have more pathogens or more antibiotic resistant bacteria than others. Nonetheless, antibiotic resistance among foodborne pathogens is a growing health concern and there is ample evidence that antibiotic use in human medicine and animal production selects for antibiotic resistant bacteria. Therefore, these important drugs should be used judiciously and prudently in both human and veterinary medicine. The associations reported in this report add more data to our understanding of the problem and further support the call to eliminate the agricultural use of antibiotics for growth promotion purposes and in the use in absence of existing disease conditions.”
Dr. Mindy Brashears, Professor of Food Safety and Public Health, Texas Tech University (webpage):
Expertise: Pre-and post-slaughter environments; emergence of antimicrobial drug resistance; meat and poultry products.
“In the report, the authors point out that recent disease outbreaks and recalls associated with ground beef were ‘all caused by Salmonella and toxic types of Escherichia coli’. While the report states that E. coli was found, there was no pathogenic E. coli found, meaning that the E. coli in the product was not disease-causing and would not cause illness. Generic (non-disease causing) E. coli lives naturally in our GI tracts and can be found naturally in the environment. It is not alarming or dangerous for it to be present in ground beef. Salmonella was in only 1% of the samples, which is consistent with USDA testing baselines that indicate that the average Salmonella prevalence is 0.9%.
“The report overstates concern over the presence of S. aureus and C. perfringens in raw ground beef. While these are foodborne pathogens that can be attributed to beef, they are only a problem if the product is mishandled. They are both concerns when found in products that have been cooked and not properly refrigerated. S. aureus is the typical “church picnic” pathogen, and must grow in the product to produce a toxin. The product must be kept above refrigeration temperatures for this to occur. C. perfringens is the typical “Thanksgiving” pathogen as it is commonly found in turkey.
“The authors link antimicrobial resistant bacteria in the samples to the use of antibiotics. However, there was resistance in the organic samples (8%) that were supposedly never exposed to antibiotics. Antimicrobial resistance is so complex that even in frozen tundra, never touched by humans or animals, we find resistant bacteria.
“Recommendations to cook the product to 160F using a meat thermometer, and to handle meat properly by refrigerating to less than 40F and preventing cross contamination, are critical to keeping the consumer safe. These recommendations are the key point, not the type of meat you buy; there is nothing of substance in this report that informs consumers on which type of beef to purchase in the supermarket with respect to food safety.”
Declared interests (see GENeS register of interests policy):
Dr. Jeffrey LeJeune: “A family member works for a coalition that advocates for the elimination of inappropriate use of antibiotics in farm animals: www.keepantibioticsworking.com.”
Dr. Mindy Brashears: “I have received research funding from the National Cattlemen’s Beef Association and the North American Meat Processors Association.”
No further interests declared.
‘Beef Report‘ Consumers Report Food Safety and Sustainability Center