Dodd defends: E. coli and salmonella in cattle production

Chuck Dodd looked fairly snappy as he defended his PhD (below, left) today – to go with his MS and DVM – but he spent much of the past three years (right), knee deep in cow poop.

Chuck’s thesis was entitled, Epidemiology of Salmonella and E. coli O157 in Beef Cattle Production Systems and included four interrelated studies:

• effects of Salmonella Newport SRP® vaccine;
• prevalence and persistence of Salmonella;
• relatedness of E. coli O157 in feces and on carcasses; and,
• a simulation model for E. coli O157 interventions.

During his defense, Chuck said he learned “you can’t test or inspect your way to food safety. It’s the entire system.”

Good for him, and best wishes. When he finally washes out the cow smell, Chuck’s off to the Landstufl Regional Medical Center in Germany.

CHUCK DODD: Eating dirt can be bad for you

New York Times journalist Jane Brody suggests that eating dirt is an instinctive behavior in humans. In her article, Eating dirt can be good for you – just ask babies, she interviewed researchers who think people should eat dirt in order to stimulate their immune system.  Brody says that immune system disorders such as asthma and allergies have risen significantly in the United States. 

Although allergies do appear to be on the rise, the awareness of allergies, the ability to diagnose allergies, and the number of people at risk (the U.S. population) have also risen significantly. 

The director of gastroenterology and hepatology at Tufts Medical Center in Boston, Dr. Joel Weinstock, said in the interview,

"There are very few diseases that people get from worms. Humans have adapted to the presence of most of them. … Children should be allowed to go barefoot in the dirt, play in the dirt, and not have to wash their hands when they come in to eat…let kids have two dogs and a cat, which will expose them to intestinal worms that can promote a healthy immune system.”

Dr. Weinstock, I’m sure glad you aren’t my doctor. 

I agree that immune systems are naturally stimulated by various exposures to the environment, and that Americans use too many antibacterial products, but I question Dr. Weinstock’s knowledge of zoonotic diseases.  Intestinal parasites from animals that infect humans, since many are not adapted to humans, often leave the intestines and migrate through the body.  There are approximately 10,000 human cases of larva migrans in the U.S. each year.  Unfortunately, most of these cases are in children, and a few of these kids die.

Eating dirt is an instinct?  Not for me.  Babies eat dirt because they don’t know better.  Some may think that bad behavior is an instinct, but calling bad behavior an instinct doesn’t excuse it.  Bad advice shouldn’t be excused either. 

Dirt may have poop in it, so don’t eat it.


CHUCK DODD: In defense of food – not Pollan

Chuck Dodd, a veterinarian and PhD student at Kansas State University, writes:

I grew up in rural Missouri eating meat and potatoes, mostly meat, and quite a bit of it.

But my carnivorous mantra doesn’t match the advice of Michael Pollan, author of In Defense of Food—An Eaters Manifesto (right). He says:

“Eat food, not too much, mostly plants.”

Most of the world already follows Michael Pollan’s advice—out of necessity.

Approximately 4.7 billion people, or over two-thirds of the world’s population, live in lower income countries where safe food and water is limited. The Food and Agriculture Organization of the United Nations (FAO) now reports that rising food prices have contributed to a global increase in malnourishment and hunger. For people living in areas of poverty or conflict, it isn’t about food choices, it’s about simply eating. My wife, Lisa (with neighbor, left), and I lived among the poor in East Africa for six years. We’ve seen hunger, malnourishment, and the effects of diarrheal disease in children–not from the safe distance of a TV screen, but among our friends.  We strived to help transform lives in difficult places.       

Many of us who live in affluent societies enjoy abundant food choices. In the U.S., we have the luxury of being able to pick our diet based upon personal preference, individual nutrients, food production systems, origin, brand, and price. For those of us who have these abundant food choices, Pollan provides additional advice:

???don’t eat anything that your great grand-mother wouldn’t recognize as food;

???avoid food products containing ingredients that are a) unfamiliar, b) unpronounceable, c) more than five in number, or that include d) high-fructose corn syrup;

???avoid food products that make health claims;

???shop the peripheries of the supermarket and stay out of the middle. (processed food products dominate the center aisles); and,

???get out of the supermarket whenever possible.

Pollan’s recommendations are clever. But some of his other recommendations, like “pay more, eat less,” would offend our African friends, like Olendorrop (right).  Olendorrop faces daily challenges in feeding his family.  In the semi-arid savannah of the Rift Valley in northern Tanzania, he struggles to raise sheep and goats, grow corn, and survive.  He has learned how to use dewormers to keep his livestock healthy.  When he uses an antibiotic to treat a sick animal, he doesn’t care about organic food.  All of his animals are grass-fed because corn is people food.  He can’t go to the supermarket because there isn’t one.  He isn’t worried about health claims and ingredients because his food doesn’t have labels.  If Olendorrop paid more and ate less, his family wouldn’t survive.

My advice: if you can afford to choose what you eat, be thankful. Being able to consider what you eat is a luxury in itself. 

Our eater’s manifesto should be to help others simply eat.  Have we, the affluent with abundant food choices, finally arrived, or have we lost touch with global reality?  Do we really need to defend our food from food science and food production systems, as Pollan writes, or do we need to defend the 923 million undernourished people in the world  who don’t have food and help transform their lives?

Bovine super-shedders and E. coli O157:H7

Chuck Dodd, a veterinarian in the U.S. Army, currently disguised as a graduate student in Food Science at Kansas State University who spends a lot of time collecting poop (right below, exactly as shown), writes that researchers have now concluded that some cows present a greater risk for beef contamination by shedding higher concentrations of Escherichia coli O157 in their feces.

Some food safety researchers, including me, have begun to label these cows as super-shedders. But that may be a witch hunt, or in this case, a super-shedder hunt.

Escherichia coli O157 remains a significant cause of foodborne illness in the United States. From 1982 to 2002, there were 350 reported outbreaks of E. coli O157 in which 8,598 people became ill. Almost 1,500 were hospitalized and 40 died. During this period, 41 percent of food-related E. coli O157 outbreaks were associated with the consumption of contaminated ground beef. Ground beef that came from cattle. Cattle that may have been shedding very high levels of E. coli O157 in their feces.

Cattle do not get sick if they carry E. coli O157 in their feces. A cow with E. coli O157 looks just like any other cow. In order to discriminate, the feces must be tested. Test methods have improved and now the organisms can be detected at lower concentrations in the feces. The numbers of organisms can also be estimated; hence, food safety researchers are able to separate the super-shedders from the low-shedders. Cattle can also be identified that are not carrying E. coli O157.

Studies have shown that E. coli O157 in cattle feces or on cattle hides is correlated with the detectable presence of E. coli O157 on the carcass. Carcass contamination likely occurs during the hide removal and evisceration process; this leads to the contamination of individual beef products sold at retail. In order to mitigate the risk of E. coli O157 contamination in ground beef, the beef industry employs pre- and post-harvest interventions. Yet some bacteria still make it through the harvest process.

Researchers are now scrutinizing cattle because their feces may have a super-sized dose of E. coli O157. Their theory: if the beef industry can detect and mitigate super-shedders, they can mitigate contamination of beef.

But is super-shedding super-bad? Maybe not.

Cattle with higher concentrations of E. coli O157 in their feces probably pose a higher risk for the eventual contamination of beef; however, the fecal shedding of these organisms comes and goes. Fecal shedding may depend upon host immunity and the environment (neither of which are the cow’s fault). What if a super-shedder on Saturday becomes a low-shedder on Sunday? What if a super-shedder is simply having a bad E. coli day? Does a high fecal concentration of E. coli O157 overwhelm the interventions that exist from farm-to-fork?

Researchers have asked whether the variation in fecal shedding “arises from the inherent stochasticity in transmission dynamics or is a signature of underlying heterogeneities in the cattle population.” Translation: are the differences in fecal shedding simply random or is it because cattle are simply different? Apparently, the fecal shedding of E. coli O157 varies by animal and by day.

Admittedly, due to the transience of E. coli O157 in cattle, a steer may shed a lot on the day of harvest. Nevertheless, if transience is real, then some days cattle may pose a high risk, low risk, or negligible risk.

The new super-shedder hunt may lengthen the path in preventing foodborne illness due to E. coli O157. Some cattle carry E. coli O157 and some don’t. There may be some benefit in knowing which cattle are shedding more than 100,000 E. coli O157 per gram in their feces on a given day, but will this knowledge prevent beef contamination? Perhaps, if it is the day of harvest.