Thursday, March 23, 2017

Bugs To Drugs: Can Probiotics Treat Depression?

Depression is a debilitating mental illness that affects up to 15 million Americans in the US alone, yet we are far from understanding the root cause. Multiple genes have been associated with depression, but whether these genes produce symptoms depends on the individual’s environment. New research is showing that one of the biggest environmental factors impinging on mental health comes from within.

Our body is home to trillions of microscopic creatures, mostly bacteria, which are collectively referred to as our microbiota. As unsettling as that may sound, these microbes are not necessarily the kind we want to evict from our body. The bacteria dwelling within our gut serve many important functions; for example, they help digestion, produce vitamins, and keep other types of microbes that cause disease at bay.

Our microbial inhabitants bring countless additional genes into our body called the “microbiome.” These microbial genes can be considered an extension of our own DNA – a so-called “second genome.” In other words, your body is not only influenced by the genes in your DNA, but it can also be affected by genes carried by your microbiota. These microbial genes not only affect physical health, but may also alter your mood and personality.

It is convenient to refer to species of our microbiota as "good" or "bad", but in reality they are neither. There are bacteria that can cause serious disease, like C-diff, but usually only after the microbiota has been disrupted (e.g. after prolonged antibiotic treatment). Likewise, "good" bacteria like E. coli can cause life-threatening disease under the right circumstances.  
Our microbiota help produce surprising amounts of neurotransmitters – chemicals that function in brain signaling. When laboratories produce “germ-free” mice by raising them in sterile environments, the mice exhibit strange neurological issues. Lacking their gut microbiota, germ-free mice do not respond to stress properly. These studies have given rise to the concept of the “gut-brain” axis, a conduit of biochemical communication between these organ systems. Such an axis exists in people too, as researchers have noted a strong correlation between intestinal problems and mental illness. For example, anxiety and depressive disorders are associated with both irritable bowel syndrome and ulcerative colitis.

A study by Ioana A. Marin and colleagues at the University of Virginia, published on March 7, 2017 in Scientific Reports, provides new evidence that intestinal bacteria influence mental disorders such as depression. In this experiment, mice were subjected to unpredictable chronic mild stress (UCMS), which involves strobe lights, irritating noise, cage tilting, and crowded conditions. Kind of like being shoved into noxious nightclubs against your will at random times throughout the day.

Unlike Disco Mickey, laboratory mice become stressed out when subjected to stimuli that resemble your average nightclub.
Over time, mice subjected to UCMS begin to show symptoms that resemble depression in humans. The researchers look for “despair behavior,” which can be detected in a number of ways. In this study, the mice were placed in a tub of water to evaluate despair behavior. Unstressed mice quickly swam to a platform and escaped, but the stressed mice did not make a strong effort to escape and had to be rescued from the tub.

The researchers then compared what the intestinal microbiome looked like in stressed versus unstressed mice. The different species of bacteria comprising the microbiota can be determined by sequencing the DNA in mouse droppings. Each species has a signature DNA sequence that serves as an identifier for that type of bacteria.

The results showed that stress altered the mouse microbiome by reducing a type of bacteria called Lactobacillus. It might have occurred to you that stress could have simply changed the eating habits of the mice, which in turn would affect the composition of the microbiome, but the researchers did not observe any change in eating habits or weight of the stressed mice. Furthermore, when they administered Lactobacillus as a probiotic, the symptoms of depression improved.

Why would stress cause changes in the microbiome? No one knows for sure, but this could be a result of altered brain chemistry making the gut less hospitable to some bacteria. Researchers also noted that intestinal physiology was altered in the stressed animals, which could have played a role in microbiota changes.

When someone consumes a probiotic they are ingesting live bacteria. That concept should no longer gross you out. Probiotics include the so-called "good" bacteria that have been shown to confer health benefits in some studies. These bacteria can be delivered into your body in numerous ways, including food (like yogurt) or pills.  
Does this mean you should rush out to purchase probiotics to battle depression? There are important caveats to studies like this that should be considered. The study was performed in a mouse model of depression, which may not fully represent the condition in humans. The microbiome of controlled laboratory animals is more uniform than humans, who tend to have vastly different bacteria in their guts depending on such things as diet, geography, illness, and age.

However, a 2016 meta-analysis (a study of studies) concluded that “probiotics were associated with a significant reduction in depression [in humans], underscoring the need for additional research on this potential preventive strategy for depression.” While that sounds encouraging, we are far from understanding how certain bacteria may ameliorate depression and whether this affect holds up in diverse patient populations. Probiotics certainly should not replace the more rigorously established treatments for depression recommended by health professionals.

Bill Sullivan is a professor at the Indiana University School of Medicine. Follow him on Twitter @wjsullivan.

Thursday, February 2, 2017

Transgender Boy Scouts

Following a lawsuit, this week the Boy Scouts of America announced that they would begin accepting members based on their gender identity rather than the gender specified on their birth certificate.


For those who do not know any transgender individuals, this might seem ridiculous. You’re either a boy or a girl, just as the doctor called it the day you were born. Consequently, the decision that transgender boys will now be accepted into the Cub Scouts and Boy Scouts has sparked outrage among some people. The outcry, which is often accompanied by shockingly cruel insults (hurled at children, no less), comes largely from folks who assume that sex and gender are the same thing.

For most people, their sex (based on their private parts) matches their gender (whether they feel or “identify” as a boy or girl). But for one in 100 people, there is a mismatch. They may anatomically look like a girl (their sex), but inside they feel like a boy (their gender).

This is not a weak or fleeting feeling to belittle – gender identity can be as strong a feeling in transgender persons as it is in non-transgender persons. The gender the brain assigns overrides whatever genitalia the body possesses.

Gender identity is the brain’s sense of being male or female, regardless of physical appearance.

A transgender boy is born with female parts, but his brain does not identify with that sex. He likes hanging out with the boys and doing typical “boy” things like eating worms off a dare and getting into heated discussions about the quantity and quality of explosions in the latest Michael Bay movie. Despite female genitalia, these children adamantly feel that they are one of the guys.

In a high-profile 2015 interview, Jenner came out as a transgender woman. In Jenner’s own words, “My brain is much more female than male…For all intents and purposes I am a woman…that female side is part of me. It's who I am." Many transgender individuals feel they were born into the wrong body and seek to align it with their gender identity through surgery.

How can this happen? A 2013 study of twins showed that there is a strong genetic component driving transsexuality. Identical twins, who share the same exact DNA, are up to 3x more likely to both be transgender than fraternal (non-identical) twins. This finding argues that genes play a major role in gender identity.

Studies in mice show that disruption of just a single gene can cause females to act like males. Female mice lacking a gene called TRPC2, which is present in brain cells and aids in pheromone recognition, displayed typical sex-crazed male behavior – these females engaged in masculine courtship rituals, pelvic thrusting, and mounting of mates. These female mice also enjoyed burping loudly and watching football with one paw down their pants.

Gender identity may also be under epigenetic control, which means the genes themselves haven’t changed but their expression levels did. One way to dampen a gene’s expression is through a chemical modification called methylation – when DNA is methylated, it represses that gene’s activity.
DNA methylation in certain parts of the brain appears to play an important role in the development of gender identity. A remarkable 2015 study showed that a drug that inhibits DNA methylation can make female rats behave like male rats.

Scientists can easily make Minnie Mouse behave more like Mickey by altering genes or gene expression.

Finally, a sophisticated array of hormones influence sexual development and impact the brain. Variations in the genes that manufacture these hormones, or their receptors, could lead to mismatches between sex and gender identity.

This is just a small sampling of the studies confirming that gender and sex are clearly separate - gene variations or changes in gene expression can make the brain assume a gender that is not consistent with the equipment down below. You cannot pick your gender identity any more than you can pick your nose. Wait, let’s rephrase that! You cannot control your gender identity any more than you can control the size of your nose.

Critics have also asserted that children who haven’t hit puberty can’t know that they are transgender. Again, science does not support such a claim. A 2015 study on transgender children has shown that gender identity emerges at a very young age (as early as two years old), and toddlers align with this gender with great conviction. To tell the child otherwise or, worse, to punish the child for acting like the gender they feel they are, can do profound psychological damage to the child’s well-being. In some cases, this has led to debilitating depression and even suicide.

Parents of transgender children are also unjustifiably persecuted, often accused of providing the child with the “wrong” environment or not raising the child the “right” way. However, as we outlined for the children above, no one is at fault here. Experts recommend that parents provide an environment that is consistent with the gender the child feels.

Just like any child, transgender kids deserve an inclusive and nurturing environment, and kudos to the BSA for living up to the Boy Scout Oath “to help other people at all times”, and to be friendly, courteous, and kind.

Contributed by:  Bill Sullivan

Tuesday, January 10, 2017

The Rise Of Superbugs: How Bacteria Defeat Antibiotics

News stations are constantly warning us about the threats of climate change, hackers, and another season of Fuller House, but what doesn't get enough press is the rise of superbugs. We're not referring to a new species of insect aliens from Starship Troopers, but rather old enemies right here on Earth. Enemies so small that a microscope is required to see them, yet so mighty that just a few of them can spell the end of your existence.

No, that's not what we mean by superbug. We're talking about pathogenic bacteria.
Throughout human history, we've been locked in an ongoing struggle with infectious disease. For much of our existence, pathogenic bacteria have wiped out huge swaths of people and kept our average life expectancy under 50 years. But thanks to the discovery of antibiotics in the early 20th century, most people are no longer dying from skin infections, pneumonia, and tuberculosis.

Alexander Fleming's discovery that a mold (Penicillium notatum) produces a substance (penicillin) capable of killing bacteria revolutionized medicine, giving us the upper hand in the war on infectious disease. However, we are now losing our advantage in this war.
Since the advent of penicillin in the 1940s, antibiotic discovery and research exploded, filling our medicine cabinets with lots of other wicked bacteria-killing drugs with crazy names like the macrolides, tetracyclines, fluoroquinolones, aminoglycosides, and more. By the 1960s, we became so complacent with our pharmacological arsenal that the majority of antibiotic research ground to a halt. Consequently, very few new antibiotics have been developed in the last half-century, leaving us caught with our pants down in the wake of bacteria that have evolved resistance to our current supply of antibiotic drugs.

Speaking of being caught with our pants down, a recent case in point is Neisseria gonorrhoeae, the bacteria that causes gonorrhea. Once easily treated with a shot of penicillin, gonorrhea has quietly evolved resistance to multiple types of antibiotics over the years. Since there is now a danger of gonorrhea being untreatable once again (!), Neisseria gonorrhoeae is considered a superbug by the CDC. Pat Benatar warned us that "Love is a Battlefield"...and now the Huey Lewis request, "I Want a New Drug", takes on an urgent new meaning.

Gonorrhea used to be a very serious infection before the discovery of antibiotics. Today, scientists are sounding the alarm that the bacteria responsible for the infection may no longer be treatable if it continues to evolve resistance and we fail to develop new antibiotics.
There are 26 antibiotic drugs approved for use in the US. Just this week, the news broke that an elderly woman died in Nevada after losing a battle with a stubborn superbug. She succumbed to an infection caused by CRE - carbapenem-resistant enterobacteriaceae (carbapenem is one of our "last resort" antibiotics that is only used when others have failed). In other words, the bacteria that killed her was immune to every single antibiotic we have in our arsenal.

So how do bacteria develop resistance to our medicines? There are at least four different ways. One, bacteria can mutate, or change, the protein that is targeted by the antibiotic. For example, penicillin inhibits a bacterial enzyme called transpeptidase, which is required by the bacteria to build its cell wall properly. Bacteria that acquire a DNA mutation that makes a slightly different version of transpeptidase can become resistant to penicillin (the new version can still build the cell wall, but no longer interacts with penicillin). A related strategy bacteria can use involves increasing the amount of the drug target; in other words, the bacteria could make more transpeptidase - too much for the drug to inhibit effectively.

Two, the bacteria can acquire a gene that makes a protein called penicillinase, which can directly attack the penicillin compound and cut it up. Some bacteria already have this gene and can pass it along to other bacteria that do not have it. Penicillinase is like a bomb diffuser - the bacterial equivalent of Sergeant First Class William James in The Hurt Locker.

Three, bacteria can mutate proteins that are needed for the antibiotic to get into the bacteria cells. Finally, bacteria can also use "efflux" proteins to pump out the antibiotic. These two related strategies effectively keep the antibiotic out of the bacteria and away from its target. A cartoon summary of these mechanisms of antibiotic resistance is shown below.

In summary, bacteria have many ways to combat the drugs we use to kill them. We need to step up our game and fast if we want to stay ahead of the devastating infections bacteria inflict upon us. We need more kryptonite to defeat the superbugs!
For more on why bacteria develop resistance to antibiotics, check out this informative video from Everyday Elements.

Contributed by:  Bill Sullivan

Blair, J., Webber, M., Baylay, A., Ogbolu, D., & Piddock, L. (2014). Molecular mechanisms of antibiotic resistance Nature Reviews Microbiology, 13 (1), 42-51 DOI: 10.1038/nrmicro3380

Tuesday, September 6, 2016

A Literal "Beer Gut"

Imagine you are a police officer and suddenly the car in front of you is beginning to drive erratically. You dismiss it at first, thinking the driver was just momentarily distracted. Then he starts swerving left and right, slowing down and then speeding up. You take a closer look inside the car. Looks like a family of four. Presumably the wife in the passenger seat, two kids in the back. The kids are behaving. He's not using his phone. The driver doesn't look distracted.

After the man nearly runs the car up on the sidewalk, you flash your lights. He pulls over without incident and appears cooperative, almost happy. Carefree, in fact.

"What's the problem, officer?" His words are slurred, virtually confirming your suspicion. This guy is three sheets to the wind (incidentally, that is an old maritime phase referring to when fasteners holding the sails became loose and control of the boat was lost).

"Have you been drinking tonight, sir?"

"Nope! Just had some spaghetti and breadsticks. Hey, I like your badge. Shiny! Can I hold your gun?" He becomes giddy with laughter.

You look over at the woman in the passenger seat. "It's true, officer. He never drinks! He gets this way after having pasta sometimes. I told him not to have seconds. How about I drive instead and we just forget the whole thing?"

Sounds like a family trying to put one over on the police, but there really is a condition called "auto-brewery syndrome" or "gut fermentation syndrome". People experience this rare condition when microbes turn the belly into a brewery. 
People with the rare condition known as "auto-brewery syndrome" can turn this carbohydrate-rich plate of pasta into enough alcohol to make them feel drunk.
A woman recently diagnosed with the syndrome had her DUI charges dismissed. She was monitored for a twelve hour period, taking a breathalyzer test every few hours. Despite having no alcohol whatsoever, her blood alcohol content rose steadily throughout the day, reaching to four times the legal limit by the end of the period.

As we've mentioned in previous articles, our body is home to trillions of microbes that collectively made up our microbiome. These microbes are largely intestinal bacteria and fungi. They perform indispensable tasks for us, such as helping to produce neurotransmitters, vitamins, and immune regulators. But on very rare occasions, certain yeasts in our gut, namely Saccharomyces cerevisiae or Candida albicans, can grow out of control and start converting carbohydrates into alcohol.

People with auto-brewery syndrome quite literally have a "beer gut". The yeast in their body can produce alcohol without the person taking a sip of booze. Some people learn to adapt and live with this higher-than-average blood alcohol content, much like anyone who builds up a tolerance to alcohol by increasing hepatic (liver) metabolism. Unbeknownst to them, some people have been living with the condition for years.

People with auto-brewery syndrome actually make alcohol in their intestines where the fungi live. So feeding them hops and tapping their stomach is not going to provide you and your friends with a ready source of free beer.
It is not known why the yeast can take such a foothold in the gut of these patients. One documented case report suggests that a course of antibiotics, which wipe out a lot of "friendly" gut bacteria but don't hurt yeast, can create an environment in the intestine that favors growth of the yeast. With the bacteria depleted, there is less competition for nutrients, so the yeast can grow out of control. Some researchers have argued that overgrowth of fungi is not to blame, but rather the patient may have genetic defects that prevent the liver from metabolizing the minute, normal levels of alcohol that may ferment in the gut. These two possibilities are not mutually exclusive.

Yeast are a type of fungi that have enzymes able to convert sugars like glucose into pyruvate, ethanol (alcohol), and carbon dioxide as waste products. One organism's waste is another organism's treasure!
In addition to creating obvious hazards and embarrassing situations, auto-brewery syndrome causes bad hangovers as well. Is there any way to alleviate this problem? One report stated that a 10 week course of anti-fungal drugs and probiotics, the latter of which aim to replenish the gut with bacteria that belong there, eliminated the condition from the patient.

So if you see someone acting like a belligerent fool for no logical reason...well, most likely they're just being a jerk. But there is a small chance that they have auto-brewery syndrome and deserve your compassion rather than condemnation.

Contributed by:  Bill Sullivan
Follow Bill on Twitter.

Cordell, B., & McCarthy, J. (2013). A Case Study of Gut Fermentation Syndrome (Auto-Brewery) with Saccharomyces cerevisiae as the Causative Organism International Journal of Clinical Medicine, 04 (07), 309-312 DOI: 10.4236/ijcm.2013.47054 

Tuesday, August 9, 2016

Potential Benefits of Thumb-sucking and Nail-biting in a Too-Clean World

In a world of Lysol and Purell, it's easy to become all-consumed with keeping clean. And why not? We're on the go more than ever now:  we're working longer hours (1, 2), spending more time commuting (3), and we’re under constant pressure to keep up to date on all the available social media networks (4). No one has time to be slowed down with the flu or a cold. So we dab on a little hand sanitizer before we eat, clean our houses regularly with bleach-containing products, and hold our breath when someone sneezes in a crowded elevator (or maybe that's just me).

But is there such a thing as being too clean? Researchers who are focused on testing this so-called "hygiene hypothesis" think there may be.

The hygiene hypothesis proposes that living in a germ-free world is disadvantageous to our health. Studies testing the hygiene hypothesis have shown correlations between our squeaky-clean developed societies and increases in allergic conditions, compared to developing societies lacking modern infrastructures that support public health (5, 6). Some studies even point to differences in the levels of allergic conditions in cities versus rural towns within the same country (7). While such studies only suggest correlations, and don't definitively show clean environments cause a predisposition to allergies, their findings are worth considering.

While the biological explanation for the hygiene hypothesis is still being studied, evidence from such studies so far suggests that when our immune systems aren't regularly challenged by germs normally present in the environments we've been co-evolving with for millennia, the result is an immune system that is predisposed to allergic reactions. Our immune systems rely on a series of specialized cells programmed and primed to respond to different pathogenic and environmental challenges in a coordinated fashion:  for example, some cells respond to bacteria and viruses while others respond to parasites. Researchers investigating biological explanations for the hygiene hypothesis have proposed that a lack of exposure to bacteria and viruses in childhood causes a shift in the population of immune cells away from cells primed and ready to attack those germs and instead toward a population of cells programed to respond to allergic stimuli (6).

Of course being clean is a good thing. An awareness of how diseases spread and how to take precautions against them is one of the reasons why modern society has been able to flourish. Hand washing and sterilization techniques introduced in the 1800s by Dr. Ignaz Semmelweis dramatically reduced a common cause of death in maternity wards (9). Modern epidemiology enables us to learn and track how certain diseases can be spread (including the recent outbreak of E. coli in flour) so we can take preventative measures to avoid further spread of diseases. We're careful to cook our food thoroughly to avoid food borne illnesses like salmonellosis. All of these behaviors protect us from unwanted illnesses, and allow us to carry on with our lives. While we certainly don't want to undo all of the advances we've made in limiting the spread of disease, evidence suggests that there needs to be a balance between being too dirty and too clean.

A line of souvenirs at Disney parks last summer included hand sanitizers featuring popular kids characters. Image from
For example, it was recently published in the journal Pediatrics (8) that thumb-sucking and nail-biting, generally thought of as being unsanitary, may help children avoid developing environmental allergies. The results came out of the Dunedin Multidisciplinary Study, in which researchers followed over 1,000 children born in Dunedin, New Zealand between 1972 and 1973 throughout adulthood. For this particular question, children were first examined at ages 5, 7, 9, and 11 and then tested for certain allergies at 13 and 32 years of age. The researchers conducting this study, Stephanie Lynch and Dr. Robert Hancox (from the University of Otago, New Zealand), and Dr. Malcolm Sears (McMaster University and St Joseph’s Healthcare, Ontario, Canada), found that the individuals who had been frequent thumb-suckers or nail-biters as children tested positive for allergic sensitivities less often than those who had not frequently engaged in those habits. More specifically, the researchers report that 49% of participants who had not been frequent thumb-suckers or nail-biters had positivity allergy tests, whereas only 31% of participants who had sucked their thumbs and bit their nails as young children had positive allergy tests. 

Granted, this is only one study and it's still probably not a good idea to advocate for children keeping their dirty hands in their mouths all of the time. After all, no one wants their child to be sick. But perhaps thumb-sucking is one thing parents don't have to worry about so much after all. Perhaps instead, we can trust that our bodies are designed to deal with those little germ and dirt exposures, and maybe even benefit from them in the long run.

Contributed by:  Kelly Hallstrom


Tuesday, July 5, 2016

Mmmm…Raw Cookie D’oh!

For several years now, the government has told Americans to put down the tube of raw cookie dough and step away. New warnings about the harrowing dangers of cookie dough were announced by the FDA last week, right before our 4th of July holiday. Seriously? You’ve been eating the stuff ever since your BFF started dating your ex in high school. What’s the big deal?

Where did things start to go wrong for Barney? Could it have been the raw cookie dough?
In this crazy, hustle and bustle world, who has the time to wait for the cookies to be cooked? Raw cookie dough allows you to savor all of the yummy cookie goodness without the grueling task of popping them into the oven and waiting 10 minutes, which feels like an eternity when you need your sugar fix. And then there’s the mess to clean up…who needs that?

So you defiantly crack open that tube and bury your face in the heavenly Play-Doh-like substance – nom nom. A few hours later, as you rest in content satisfaction on the couch, you begin to feel a great disturbance in The Force. An abrupt gurgle begins to percolate in your gut. Your stomach makes a demonic growl. Visions of volcanic eruptions suddenly waft through your woozy head. The horrific bout of bloody diarrhea that follows might be enough to convince you to listen to those pesky scientists at the FDA from now on. The intestinal apocalypse you experience may even have you wishing for death, but don’t do so lightly. Raw cookie dough has been known to kill.

Linda Rivera died in 2013, a victim of eating a few spoonfuls of raw cookie dough. Over 70 other people were sickened during this outbreak, which started in 2009 and affected mostly teenage girls and children.
How could something that tastes so good be so bad for you? Your first instinct might be the raw eggs in the dough, which could be contaminated with a common food poisoning bacterium, Salmonella. While this is indeed possible, the latest round of scares stem from flour contaminated with a particularly nasty strain of the bacterium Escherichia coli (E. coli). Shiga toxin-producing E. coli O121 has been identified as the culprit behind a massive recall of contaminated flour made by General Mills. Most E. coli strains are harmless, but this one is so not harmless.

Now you might be wondering:  how does E. coli, a bacterial species that inhabits the gut, get into flour? Flour comes from grain grown in fields where animals may do their business - not the kind of "chocolate chips" you want in your cookie dough! But the grain is not normally sterilized because manufacturers assume that people would actually cook the items made from that flour, which kills the E. coli. However, some people just want the “goods” and not the “baked” part.

The Shiga toxin produced by this type of E. coli is the cause for the alarm – these are proteins made by the bacteria that can bind to receptors on our cells, particularly in the intestine and the kidney, which is why people experience bloody diarrhea and renal failure when infected. Once inside our cells, the Shiga toxin can bind to our ribosomes, which make our cellular proteins. When our cells can’t make proteins, they eventually die.

E. coli bacteria are kind of scruffy-looking, but those “hairs” are actually flagella the bacterium uses to get around. About 10,000 of these can fit on the head of a pin. It only takes 10 of the more virulent strains to make you seriously ill.
Over 40 people have been sickened from the recent outbreak, almost a baker's dozen requiring hospitalization. There have been no deaths to date, and deaths from cookie dough remain extremely rare…but it has happened and is a most unpleasant way to leave the world. So cook your cookies or risk tossing them later.

The FDA also warned that pizza dough, “play clay” made from dough, or “flour crafts” that kids sometimes play with, can also lead to food poisoning. Even if they don’t eat it, the E. coli can get onto their hands, which usually end up in their mouth before they get washed.
In light of these cookie dough poisonings, manufacturers have started to use only pasteurized eggs and, more recently, heat-treated flour to destroy the bacterial culprits. However, they still caution that consumers cook the product properly to be on the safe side.

What about those of us who enjoy our desserts within a dessert, namely cookie dough ice cream? You can breathe easy - cookie dough ice cream is okay to eat because it is typically made with heat-treated flour and pasteurized eggs.
To put things in perspective, E. coli contaminated spinach sickened nearly 200 people and killed 3 of them in 2006. The point is not to eat more cookie dough instead of spinach (sorry)…but to handle and prepare ALL food properly no matter what it is.

Putting it all together, if you are making cookie dough or cake batter from scratch, odds are the flour you're using has not been heat-treated to kill bacteria, so there is a chance it could be contaminated. Even if it is not under the recall, the flour should be treated as you would any other raw food. If you must play cookie dough roulette, some companies are stepping up to the (kitchen) plate and making some that lacks eggs and uses heat-treated flour.

Contributed by:  Bill Sullivan

Thorpe, C. (2004). Shiga Toxin--Producing Escherichia coli Infection Clinical Infectious Diseases, 38 (9), 1298-1303 DOI: 10.1086/383473

Obrig, T. (2010). Escherichia coli Shiga Toxin Mechanisms of Action in Renal Disease Toxins, 2 (12), 2769-2794 DOI: 10.3390/toxins2122769