E. Coli Vaccine for Cows: No Substitute for Grazing

The USDA has conditionally approved a new vaccine to reduce deadly E. coli bacteria in cows, but at $10 a head, it would cost $400 million annually to vaccinate the
nation’s cattle, with the expectation of reducing the prevalence of E.
coli by 85%, at most. Additional slaughterhouse food safety precautions, including cleaning and testing, would have to be taken to ensure E. coli-free beef.

Putting the wisdom of this plan in doubt, the long-term effectiveness of the vaccine could not be guaranteed, as the bacteria is likely to develop a resistance to it over time. The sum of these concerns make alternatives to the vaccine more attractive.

One alternative is to require cows to be fed grass. If the industry is ready to shell out $10 a head on a vaccine, maybe it could try feeding cows grass for the 5 days prior to slaughter, instead. This has been shown to reduce E. coli by a factor of 1000, both cheaper and more effective than the vaccine.

Nina Planck explained the origins of and solutions to E. coli O157, in her 2006 article in the New York Times:

It’s not found
in the intestinal tracts of cattle raised on their natural diet of
grass, hay and other fibrous forage. No, O157 thrives in a new – that
is, recent in the history of animal diets – biological niche: the
unnaturally acidic stomachs of beef and dairy cattle fed on grain, the
typical ration on most industrial farms. It’s the infected manure from
these grain-fed cattle that contaminates the groundwater and spreads
the bacteria to produce, like spinach, growing on neighboring farms.

In 2003,

The Journal of Dairy Science
noted that up to 80 percent of dairy cattle carry O157. (Fortunately,
food safety measures prevent contaminated fecal matter from getting
into most of our food most of the time.) Happily, the journal also
provided a remedy based on a simple experiment. When cows were switched
from a grain diet to hay for only five days, O157 declined 1,000-fold.

This
is good news. In a week, we could choke O157 from its favorite home –
even if beef cattle were switched to a forage diet just seven days
before slaughter, it would greatly reduce cross-contamination by manure
of, say, hamburger in meat-packing plants. Such a measure might have
prevented the E. coli outbreak that plagued the Jack in the Box fast
food chain in 1993.

Unfortunately, it would take more than a
week to reduce the contamination of ground water, flood water and
rivers – all irrigation sources on spinach farms – by the
E-coli-infected manure from cattle farms.

The United States
Department of Agriculture does recognize the threat from these huge
lagoons of waste, and so pays 75 percent of the cost for a confinement
cattle farmer to make manure pits watertight, either by lining them
with concrete or building them above ground. But taxpayers are
financing a policy that only treats the symptom, not the disease, and
at great expense. There remains only one long-term remedy, and it’s
still the simplest one: stop feeding grain to cattle.

Background on the E. Coli vaccine gathered from various news sources:

Most E. coli bacteria are harmless but one kind, known as O157,
sickens an estimated 70,000 and kills 61 people in the U.S. every year, according to
the Centers for Disease Control and Prevention. Most people exposed to E. coli O157 recover in
a few days, but some get serious complications such as kidney failure which can lead to death. Contaminated beef is a common source of infection and has led to
several big meat recalls in recent years.

The most recent large-scale E. coli-related recall put Topps Meat, a $31 million company with $29.3 million in revenues, out of business. On September 29, 2007, Topps recalled 21.7 million pounds of its frozen hamburgers — a year’s worth of production — after 30 people in 8 states had E. coli infections matching the strain found in the Topps patties.

Dairy and beef producers have invested $27 million since 1993 in research fighting this pathogen. Now, there is a vaccine, made by Epitopix, that works by preventing E. coli O157 present in cows’ intestines
from absorbing iron. The company’s technology takes the proteins that
the bacteria uses to absorb iron from the host animal, and injects them
back into cattle to generate an immune response against those proteins.
Without the proteins, the bacteria can’t absorb the iron and dies.

With fewer bacteria in the cows’ intestines, the risk is reduced that the bacteria will contaminate the carcass at slaughter.

The first time the material was tried in a Kansas State university feedlot situation, it decreased shedding of E. coli by 54 percent. When the research team at Kansas State and West Texas A&M University increased the dose, shedding of E. coli was knocked down by 85 percent.

Guy Loneragen, who headed the Texas portion of the trials, said at a beef research meeting last year that the 85 percent kill rate means handling the remaining bacteria is “within the capacity” of in-plant safety measures like washing the hides before slaughter, washing the carcasses, and microbial laboratory testing.

But, a new tool to prevent E. coli spread may encourage some meat producers to continue the untenable
conditions of slaughterhouses instead of changing them.

Meat
producers are unlikely to change their practices except through regulation or consumer demand.

Another concern is that, just as bacteria can develop antibiotic resistance, they can
develop resistance to a vaccine as well.

Because the pathogen doesn’t sicken
cattle, it’s unclear how vigorously cattle producers will embrace the
vaccine.

Epitopix estimates the
vaccine will eventually protect 10 million cattle on animal feed a
year, or a quarter of the country’s annual cattle supply.

Epitopix has not yet set a price for a course of its vaccine, but Bioniche, its Canadian competitor has said its vaccine would likely cost less than $10 per head
of cattle.

Sources:

E. coli vaccine approved for cows — thoughts and concerns

Ho Phang

Food Safety Smart

March 13, 2009

http://foodsafetysmart.com/2009/03/13/e-coli-vaccine-approved-for-cows-thoughts-and-concerns/

USDA grants conditional license for E coli cattle vaccine

Lisa Schnirring

CIDRAP News

Mar 11, 2009

http://www.cidrap.umn.edu/cidrap/content/fs/food/news/mar1109coli.html

United States — Vaccine for Cattle