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2011 Feedlot Study Finds E. coli Strains in Fecal Pools

The year before USDA’s new groundbreaking non-O157 E. coli policy went into effect, the agency went back to America’s feedlots to find out just how prevalent six new strains were at the source.

The 2011 study into the prevalence of Escherichia coli O-Types and Shiga-Toxin genes in fecal samples from feedlots is being published in the current issue of the pricey journal, Foodborne Pathogens and Disease.

According to the abstract for that study, which is behind a $51.00 pay wall, the July to October 2011 investigation into 21 feedlots that volunteered for the study found one or more E. coli O-serogroups in 44.2 percent of the 1,145 fecal pools that were evaluated.

The pool prevalence for E coli strains was:

  • O157 – 19.7 percent
  • O45 – 13.8percent
  • O103 – 9.9 percent
  • O121 – 9.3 percent
  • O145 – 5.5 percent
  • O36 – 1.1 percent
  • O26 – 0.5 percent

“While efforts to control foodborne illness associated with Shiga toxin-producing Escherichia coli (E. coli) O157 through processes and procedures implemented at harvest facilities have been very successful, there is concern about the burden of illness associated with other Shiga toxin-producing E. coli,” the study says.

The 2011 feedlot study was conducted at the behest of USDA’s Animal and Plant Health Inspection Service by the Centers for Epidemiology and Animal Health at Colorado State University and the Kansas State Veterinary Diagnostic Laboratory.

“Little is known about the prevalence and distribution of these E. coli in the animal production environment,” the researchers said, referring to the six additional strains that were classified as adulterants and became subject to testing after June 4, 2012.

The feedlot testing occurred almost a year earlier involved taking individual fecal swabs collected from cattle 60 days after they arrived in the feedlot and then pooling them for evaluation using polymerase chain reaction assay to identify the presence of all seven strains of E. coli that are now banned.

E. coli O157:H7 was first recognized a foodborne pathogen associated with consumption of ground beef in 1982. It gained worldwide attention with the Jack-in-the-Box outbreak 20 years ago when nearly 700 illnesses and four deaths occurred. E coli O157:H7 has been banned from beef since 1994.

“Nearly all pools were positive for ehxA (99.7 percent) or stx2 (98.6 percent), “ according to the study abstract. “The pool level prevalence for stx1 and eae was 65.5 percent and 69.3 percent, respectively. Pools that were positive for one or more of the other E. coli O-serogroups were 1.37 times more likely to be positive for E. coli O157.

“Conversely, pools that were positive for E. coli O157 were 1.43 times more likely to be positive for at least one of the other E. coli O-serogroups evaluated. These data will be useful to understand the expected prevalence of potential Shiga toxin–producing E. coli in cattle feedlots.”

The CSU/KSU feedlot study for the Animal and Plant Health Inspection Service marked the third time since 1999 that USDA went to where cattle are held to conduct research.

© Food Safety News
  • ChurnYourOwn

    Deprive a ruminant access to its native diet of plants growing on pasture – feed it instead with pesticide-drenched genetically engineered corn, soy and alfalfa and guess what? The cow gets violently ill and harbors dangerous pathogens. So then we go hog wild with antibiotics and guess what? We create new, antibiotic-resistant strains of pathogens. It’s a vicious cycle that we’re never going to win. Mother nature will continue to outsmart us.

    For some reason we refuse to want to address the root cause of the problem. Why would we ever do that? Meat would be more expensive then. Heaven forbid we redirect any of the gobs of money we’re pouring into healthcare, drug research and regulation and inspection into improving the quality of our food supply and getting at least to the level of purity, safety and labeling that exists in Europe. No way. Instead, we have to create new antibiotics, preach to consumers that they should never expect to be able to consume animal products raw or rare, and then pour ever more money into regulations that serve no benefit to society, but only to put small producers out of business and further line the pockets of the highly profitable industrial agribusiness giants.

  • Mike_Mychajlonka_PhD

    I have raised this question before but have yet to run across a satisfying answer.  If the these different varieties of STEC are found in the CAFO wastestreams, why are they apparently not causing illness, neither in CAFO employees nor in persons living in and around a CAFO – i.e., those folks exposed to STEC in the raw?  Put another way, what is it that makes an undercooked hamburger such a deadly-efficient delivery system for STEC?

  • Jamie Salcedo

    What’s always really freaked me out is the thought of STEC strong enough to get past any sterilzation efforts before delivery. Imagine food grade tanks that become repositories for them!

    • Mike_Mychajlonka_PhD

      I agree.  I once asked a representative of a food transport firm (who shipped mostly produce) to explain how and how often trucks were cleaned.  His reply was not to worry, each truck was spray-cleaned with hot water every couple of weeks.  When I asked how hot the water actually was, he did not know.  I was more worried after I heard his answer than before.  Most food folk in my experience do not really have an intuitive idea of how small bacteria actually are, how quickly they multiple nor how high their numbers can become.  For example, a saline solution containing 100,000 cells of STEC per milliliter would look crystal clear to the naked eye.  Our ability to manipulate bacterial genetics depends upon the fact that, in the bacterial world, events occurring with what we would consider a negligible frequency (i.e., one in a million) are a virtual certainty.  Such statistical uncertainty is, I think, under-appreciated to the point that it complicates sanitation efforts altogether.  It is not that STEC are any more resistant to sanitation efforts than other E. coli, just that the standards we work towards must reflect their tiny size and potentially large numbers and often doesn’t.  Folks tend to stick with sanitation methods they understand and are comfortable with (even if those same methods gets a plant in trouble with the downstream water treatment facility) and gloss over methods that, while unfamiliar, may be more effective in a given situation.

  • oldcowvet

    let’s see where to begin.  0157 was recognized well before introduction of gmo crops.  o157 is a normal resident in ruminant gi tracts.  abx resistance has nothing to do with 0157,  grazed cattle can also carry e coli, infact, rotational grzed cattle suffer the same acidosis as grain fed cattle.  cattle have been fed out on corn soy diets 75+ years.  i could go on and on.  lets adress the real problems, not a ton off straw cows, er men