Clostridium difficile in the Food Supply

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Clostridium difficile is one of our most urgent bacterial threats, sickening a quarter million Americans every year, and killing thousands at the cost of a billion dollars a year. And it's on the rise.

As shown in C. difficile Superbugs in Meat, uncomplicated cases have been traditionally managed with powerful antibiotics, but recent reports suggest that hypervirulent strains are increasingly resistant to medical management. There's been a rise in the percentage of cases that end up under the knife, which could be a marker of the emergence of these hypervirulent strains. Surgeons may need to remove our colon entirely to save our lives, although the surgery is so risky that the operation alone may kill us half the time.

Historically, most cases appeared in hospitals, but a landmark study published in the New England Journal of Medicine found that only about a third of cases could be linked to contact with an infected patient.

Another potential source is our food supply.

In the US, the frequency of contamination of retail chicken with these superbugs has been documented to be up to one in six packages off of store shelves. Pig-derived C. diff, however, have garnered the greatest attention from public health personnel, because the same human strain that's increasingly emerging in the community outside of hospitals is the major strain among pigs.

Since the turn of the century, C. diff is increasingly being reported as a major cause of intestinal infections in piglets. C. diff is now one of the most common causes of intestinal infections in baby piglets in the US. Particular attention has been paid to pigs because of high rates of C. diff shedding into their waste, which can lead to the contamination of retail pork. The U.S. has the highest levels of C. diff meat contamination tested so far anywhere in the world.

Carcass contamination by gut contents at slaughter probably contributes most to the presence of C. diff in meat and meat products. But why is the situation so much worst in the US? Slaughter techniques differ from country-to-country, with those in the United States evidently being more of the "quick and dirty" variety.

Colonization or contamination of pigs by superbugs such as C. difficile and MRSA at the farm production level may be more important than at the slaughterhouse level, though. One of the reasons sows and their piglets may have such high rates of C. diff is because of cross-contamination of feces in the farrowing crate, which are narrow metal cages that mother pigs are kept in while their piglets are nursing.

Can't you just follow food safety guidelines and cook the meat through? Unfortunately, current food safety guidelines are ineffective against C. difficile. To date, most food safety guidelines recommend cooking to an internal temperature as low as 63o C-the official USDA recommendation for pork-but recent studies show that C. diff spores can survive extended heating at 71o. Therefore, the guidelines should be raised to take this potentially killer infection into account.

One of the problems is that sources of C. diff food contamination might include not only fecal contamination on the surface of the meat, but transfer of spores from the gut into the actual muscles of the animal, inside the meat. Clostridia bacteria like C. diff comprise one of the main groups of bacteria involved in natural carcass degradation, and so by colonizing muscle tissue before death, C. diff can not only transmit to new hosts that eat the muscles, like us, but give them a head start on carcass break-down.

Never heard of C. diff? That's the Toxic Megacolon Superbug I've talked about before.

Another foodborne illness tied to pork industry practices is yersiniosis. See Yersinia in Pork.

MRSA (Methicillin-resistant Staph aureus) is another so-called superbug in the meat supply:

More on the scourge of antibiotic resistance and what can be done about it:

How is it even legal to sell foods with such pathogens? See Salmonella in Chicken & Turkey: Deadly But Not Illegal and Chicken Salmonella Thanks to Meat Industry Lawsuit.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: USDA / Flickr. This image has been modified.

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Clostridium difficile in the Food Supply

Clostridium difficile in the Food Supply.jpeg

Clostridium difficile is one of our most urgent bacterial threats, sickening a quarter million Americans every year, and killing thousands at the cost of a billion dollars a year. And it's on the rise.

As shown in C. difficile Superbugs in Meat, uncomplicated cases have been traditionally managed with powerful antibiotics, but recent reports suggest that hypervirulent strains are increasingly resistant to medical management. There's been a rise in the percentage of cases that end up under the knife, which could be a marker of the emergence of these hypervirulent strains. Surgeons may need to remove our colon entirely to save our lives, although the surgery is so risky that the operation alone may kill us half the time.

Historically, most cases appeared in hospitals, but a landmark study published in the New England Journal of Medicine found that only about a third of cases could be linked to contact with an infected patient.

Another potential source is our food supply.

In the US, the frequency of contamination of retail chicken with these superbugs has been documented to be up to one in six packages off of store shelves. Pig-derived C. diff, however, have garnered the greatest attention from public health personnel, because the same human strain that's increasingly emerging in the community outside of hospitals is the major strain among pigs.

Since the turn of the century, C. diff is increasingly being reported as a major cause of intestinal infections in piglets. C. diff is now one of the most common causes of intestinal infections in baby piglets in the US. Particular attention has been paid to pigs because of high rates of C. diff shedding into their waste, which can lead to the contamination of retail pork. The U.S. has the highest levels of C. diff meat contamination tested so far anywhere in the world.

Carcass contamination by gut contents at slaughter probably contributes most to the presence of C. diff in meat and meat products. But why is the situation so much worst in the US? Slaughter techniques differ from country-to-country, with those in the United States evidently being more of the "quick and dirty" variety.

Colonization or contamination of pigs by superbugs such as C. difficile and MRSA at the farm production level may be more important than at the slaughterhouse level, though. One of the reasons sows and their piglets may have such high rates of C. diff is because of cross-contamination of feces in the farrowing crate, which are narrow metal cages that mother pigs are kept in while their piglets are nursing.

Can't you just follow food safety guidelines and cook the meat through? Unfortunately, current food safety guidelines are ineffective against C. difficile. To date, most food safety guidelines recommend cooking to an internal temperature as low as 63o C-the official USDA recommendation for pork-but recent studies show that C. diff spores can survive extended heating at 71o. Therefore, the guidelines should be raised to take this potentially killer infection into account.

One of the problems is that sources of C. diff food contamination might include not only fecal contamination on the surface of the meat, but transfer of spores from the gut into the actual muscles of the animal, inside the meat. Clostridia bacteria like C. diff comprise one of the main groups of bacteria involved in natural carcass degradation, and so by colonizing muscle tissue before death, C. diff can not only transmit to new hosts that eat the muscles, like us, but give them a head start on carcass break-down.

Never heard of C. diff? That's the Toxic Megacolon Superbug I've talked about before.

Another foodborne illness tied to pork industry practices is yersiniosis. See Yersinia in Pork.

MRSA (Methicillin-resistant Staph aureus) is another so-called superbug in the meat supply:

More on the scourge of antibiotic resistance and what can be done about it:

How is it even legal to sell foods with such pathogens? See Salmonella in Chicken & Turkey: Deadly But Not Illegal and Chicken Salmonella Thanks to Meat Industry Lawsuit.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: USDA / Flickr. This image has been modified.

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Is Liquid Smoke Safe?

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We know smoke inhalation isn't good for us, but what about smoke ingestion? Decades ago, smoke flavorings were tested to see if they caused DNA mutations in bacteria--the tests came up negative. Even as more and more smoke flavoring was added, the DNA mutation rate remained about the same.

But the fact that something is not mutagenic in bacteria may have little predictive value for its effect on human cells. A group at MIT tested a hickory smoke flavoring they bought at the store against two types of human white blood cells. Unlike the bacteria, the mutation rate shot up as more and more liquid smoke was added. But, "there is no evidence that mutagenic activity in a particular human cell line is more closely related to human health risk than is mutagenic activity in bacteria." In other words: just because liquid smoke causes DNA mutations to human cells in a petri dish, doesn't mean that it does the same thing within the human body.

A good approach may be to just analyze liquid smoke for known carcinogens, chemicals that we know cause cancer.

Damaging DNA is just one of many ways chemicals can be toxic to cells. A decade later researchers tested to see what effect liquid smoke had on overall cell viability. If you drip water on cells, nothing happens, they keep powering away at around 100% survival, but drip on more and more wood fire smoke, and you start killing some of the cells off. Cigarette smoke is more toxic, but three out of four of the brands of liquid smoke they bought at the supermarket killed off even more cells, leading them to conclude that the cytotoxic potential of some commercial smoke flavorings is greater than that of liquid cigarette smoke, a finding they no doubt celebrated given that the researchers were paid employees of the R. J. Reynolds Tobacco Co.

Unfortunately they didn't name names of the offending brands. That's one of the reasons I was so excited about a new study, where they tested--and named--15 different brands of liquid smoke. This maximum "response" they were measuring was p53 activation.

P53 is a protein we make that binds to our DNA, you can see this illustrated in my video, Is Liquid Smoke Flavoring Carcinogenic?. It activates our DNA repair enzymes. So a big p53 response may be indicative of a lot of DNA damage,and a few of the liquid smoke flavorings activated p53 almost as much as a chemotherapy drug like etoposide, whose whole purpose is to break DNA strands.

Other flavorings didn't seem as bad, though there was a hickory smoke powder that ranked pretty high, as did the fish sauce, though smoked paprika didn't register at all.

The p53-activating property in liquid smoke was eliminated by standard baking conditions (350°F for 1h), so if you're baking something with liquid smoke for long enough, it should eliminate this effect, though just boiling--even for an hour, or slow cooking doesn't appear to work.

They conclude "If the DNA-damaging activities of liquid smoke were thought to be deleterious, it might be possible to replace liquid smoke with other safer, smoky substances." Why do they say if thought to be deleterious? That's because they're not really measuring DNA damage, they're measuring p53 activation, and that's not necessarily a bad thing.

P53 is considered "Guardian of our Genome," guardian of our DNA. It's considered a tumor suppressor gene, so if something boosts its activity is that good or bad? It's like the broccoli story. Cruciferous vegetables dramatically boost our liver's detoxifying enzymes. Is this because our body sees broccoli as toxic and is trying to get rid of it quicker? Either way, the end result is good, lower cancer risk.

It's a biological phenomenon known as hormesis - that which doesn't kill us may make us stronger. Like exercise is a stress on the body, but in the right amount can make us healthier in the long run. So, for example, teas and coffees caused p53 activation as well, but their consumption is associated with lower cancer risk. So it's hard to know what to make of this p53 data. Due to the limitations of the available tests it's hard to calculate the genotoxic potential of liquid smoke, or any other food for that matter. A better approach may be to just analyze liquid smoke for known carcinogens, chemicals that we know cause cancer.

This was first attempted back in 1971. One of the seven liquid smoke flavors researchers tested contained one polycyclic aromatic hydrocarbon known to be cancer-causing, but there's a bunch of similar carcinogens researchers didn't test for. A later study, however, tested across the board, looking specifically at five different carcinogens in retail liquid smoke seasonings.

The recommended daily upper safety limit for these carcinogens is 47. Hickory smoke flavoring has only 0.8 per teaspoon, so we'd have to drink three bottles a day to bump up against the limit. And mesquite liquid smoke has only 1.1.

It turns out that most of the carcinogens in smoke are fat soluble, so when we make a water-based solution, like liquid smoke, we capture the smoke flavor compounds without capturing most of the smoke cancer compounds. The only time we need to really worry is when eating smoked foods--foods directly exposed to actual smoke. For example, smoked ham has 21.3 per serving, and smoked turkey breast has 26.7 per serving. One sandwich and we may be halfway to the limit, and one serving of barbequed chicken takes us over the top. Eating less than a single drumstick and we nearly double our daily allotment of these carcinogens. Nothing, however, is as bad as fish. Smoked herring? 140 per serving. And smoked salmon? One bagel with lox could take us ten times over the limit.

I've touched on those cooked meat carcinogens before. In Estrogenic Cooked Meat Carcinogens I explored the role of these cooked meat chemicals in tumor growth. PhIP: The Three Strikes Breast Carcinogen explored their role in cancer invasion. Reducing Cancer Risk In Meateaters offered some mediation strategies. Heterocyclic Amines in Eggs, Cheese, and Creatine? showed how even vegetarians may be at risk and Cancer, Interrupted: Green Tea and Cancer, Interrupted: Garlic & Flavonoids explored some counter measures.

Some smoke compounds may be a concern even if we don't eat them. See Meat Fumes: Dietary Secondhand Smoke. Even the smell of frying bacon may be carcinogenic: Carcinogens in the Smell of Frying Bacon.

Some plant foods exposed to high temperatures may also present a concern. See Is Yerba Mate Tea Bad for You? and Acrylamide in French Fries. What about Carcinogens in Roasted Coffee?

The broccoli liver enzyme boost story is covered in The Best Detox.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: eric forsberg / Flickr

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Meat Industry Wins Right to Sell Tainted Meat

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In my last post, I talked about a particularly virulent strand of Salmonella traced to Foster Farms. But while even Mexico banned the importation of Foster Farms' chicken on public health grounds, it was still sold in the United States. Why wasn't there a recall? How could Foster Farms continue to legally sell chicken contaminated with this virulent strain of Salmonella? It all goes back to Supreme Beef v. USDA, a court case in which the meat industry sued the USDA after they had the audacity to try to shut down a slaughter plant that was repeatedly found violating Salmonella standards. The meat industry won. The Federal Appeals Court ruled that it wasn't illegal to sell contaminated meat; what was illegal was the USDA trying to protect the public by shutting down the plant. Because normal cooking practices destroy Salmonella, the presence of Salmonella in meat does not render the meat "injurious to health." Salmonella-infected meat is thus legal to sell to the consumer.

We can get infected no matter how well the meat is cooked though. According to researchers, even though consumers "may eliminate Salmonella on ready-to-cook chicken by proper cooking, they could still be exposed to and acquire a Salmonella infection from cross-contamination of other foods with Salmonella from raw chicken during meal preparation." If we measure the transfer rate from naturally contaminated poultry legs purchased in supermarkets to cutting boards in the kitchen, overall, 80% of the leg skins in contact with the cutting board for ten minutes transferred Campylobacter (another dangerous bacteria found in chicken feces) infection to the cutting board. And then if we put cooked chicken back on that same cutting board, there's about a 30% chance it too will become contaminated.

Even though people know that washing hands can decrease the risk of food poisoning, only about 2/3 say they actually do it. Even though most people know about cross contamination, 1/3 don't even say they wash their cutting boards. Though awareness appears to be growing, even when people wash the cutting boards with hot soapy water we can still find Salmonella and Campylobacter (see Avoiding Chicken to Avoid Bladder Infections). The reason most people have more bacteria from feces in their kitchen than their bathroom is because people rinse their chickens in the sink, not the toilet .

Foster Farms swore they'd try to reduce the number of chickens they were producing with this virulent strain of Salmonella from 1 in 4 to just 1 in 20. Why not a zero tolerance policy in countries such as Sweden? Because then, as the head of food safety for Costco noted, "you wouldn't have a poultry industry."

Other countries have been able to raise chickens without Salmonella. One industry-funded scientist complained that if the entire onus to produce safe products is placed on industry, "it then gives the consumer no personal responsibility to handle their product correctly." That's like a car company saying we can't make safe cars because then no one will wear a seat belt.

I've touched on this topic before in my videos Salmonella in Chicken and Turkey Deadly but Not Illegal, Zero Tolerance to Acceptable Risk, and Unsafe at Any Feed.

More on the issue of cross-contamination in:

Note when it comes to egg-borne infection the issue is not just cross-contamination, given Salmonella can survive the most common egg cooking methods. Check out my video Total Recall.

Though some meat additives may make meat safer (Viral Meat Spray and Maggot Meat Spray), others may increase the food safety risk. See my video Phosphate Additives in Chicken.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videoshere and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Danny Huizinga / Flickr

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The Top Three DNA Protecting Spices

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In my video Which Spices Fight Inflammation? I profile a landmark study that compared the ability of different spices to suppress inflammation. The study also compared the spices' ability to protect DNA. Cloves, ginger, rosemary, and turmeric were able to significantly stifle the inflammatory response, but can they also protect DNA?

If a tissue sample is taken from a random person, about 7% of their cells may show evidence of DNA damage, actual breaks in the strands of their DNA. If we then blast those cells with free radicals, we can bring that number up to 10%. But if the person has been eating ginger for a week, DNA damage drops to just 8%. In the video, Spicing Up DNA Protection, you can see a comparison of DNA damage in cells from people eating different spices. Those who hadn't been eating any herbs or spices were vulnerable to DNA damage from oxidative stress. But just including ginger in our diet may cut that damage by 25%--the same with rosemary.

Turmeric is even more powerful--DNA damage was cut in half. And this was not just mixing turmeric with cells in some petri dish: This is comparing what happens when you expose the cells of spice eaters versus the cells of non-spice eaters to free radicals and count the DNA fracture rates.

And not only did the turmeric work significantly better, but it did so at a significantly smaller dose. One and a third teaspoons a day of ginger or rosemary was compared to practically just a pinch of turmeric (about an eighth of a teaspoon a day)--that's how powerful the stuff is. I encourage everyone to cook with this wonderful spice. It tastes great and may protect every cell in our body, with or without the added stress. Counting the DNA breaks in people's cells before and after a week of spices without the free radical blast revealed no significant intrinsic protection in the ginger or rosemary groups. However, the turmeric still appeared to reduce DNA damage by half.

This may be because curcumin is not just an antioxidant--it also boosts the activity of the body's own antioxidant enzymes. Catalase is one of the most active enzymes in the body: each one can detoxify millions of free radicals per second. If we consume the equivalent of about three quarters of a teaspoon of turmeric a day, the activity of this enzyme in our bloodstream gets boosted by 75%!

I suggest cooking with it rather than, for example, just throwing it in a smoothie. Why? Because this effect was found specifically for heat-treated turmeric. In practice, many herbs and spices are only consumed after cooking, so the researchers tested turmeric and oregano in both raw and cooked forms. In terms of DNA damage, the results from raw turmeric did not reach statistical significance. However, the opposite was found for its anti-inflammatory effects. So we might want to eat it both ways.

"Practical recommendations for obtaining curcumin in the diet might be to add turmeric to sweet dishes containing cinnamon and ginger." I add it to my pumpkin pie smoothies (a can of pumpkin, frozen cranberries, pitted dates, pumpkin pie spice and some nondairy milk). We can also cook with curry powder or turmeric itself. The researchers suggest something called "turmeric milk," which is a traditional Indian elixir made with milk, turmeric powder, and sugar. I'd suggest substituting a healthier sweetener and a healthier milk. Soy milk, for example, might have a double benefit. If you're taking turmeric to combat inflammation, osteoarthritis sufferers randomized to soy protein ended up with significantly improved joint range of motion compared to dairy protein.

For some other extraordinary benefits of spices, see:

There are a few herb and spice caveats. See, for example:

Too much turmeric may also not be a good idea for those at risk for kidney stones (See Oxalates in Cinnamon).

Feel free to check out my Healthy Pumpkin Pie recipe for another way to spice up your diet.

-Michael Greger, M.D

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Todd Huffman / Flickr

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Should Carrageenan Be Avoided?

 

 

 

 

 

 

 

 

Should Carrageenan Be Avoided?

Six hundred years ago, people living along the coast of Carragheen County Ireland started using a red algae, which came to be known as Irish moss, to make a jellied dessert. This moss is now the source of carrageenan, a fat substitute (perhaps most famously used in the failed McLean Deluxe) and a food additive used as a thickener in dairy and nondairy products.

In 2008 I raised a concern about carrageenan. We had known for decades that it had harmful effects on laboratory animals, but in 2008 the first study on human cells to “suggest that carrageenan exposure may have a role in development of human intestinal pathology” was conducted. This was all five years ago, though. What’s the update? (See Is Carrageenan Safe?)

After the activation of inflammatory pathways was demonstrated in actual human colon tissue samples, Europe pulled it from infant formula, concerned that infants might be getting too much at such a vulnerable age. The latest suggests carrageenan consumption could possibly lead to a leaky gut by disrupting the integrity of the tight junctions that form around the cells lining our intestine—the barrier between our bloodstream and the outside world. This was just an in vitro study, though, done in a Petri dish. We still don’t know what effects, if any, occur in whole human beings. Some researchers advise consumers to select food products without carrageenan, accusing the FDA of “ignoring [its] harmful potential.”

Personally, after having reviewed the available evidence, I continue to view carrageenan the way I view acrylamide, another potential, but unproven hazard. Acrylamide is a chemical formed by cooking carbohydrates at high temperatures. So should we avoid eating such foods, like the EPA suggests? Well, “Food safety concerns must also be considered [in the context of dietary] consequences.” Where’s it found the most? Foods that are already unhealthy.

So sure, we can use our concern about the probable carcinogen,acrylamide as yet another reason to avoid potato chips and French fries, but until we know more I wouldn’t cut out healthful foods like whole grain bread. (For more on Acrylamide, see my video Acrylamide in French Fries).

Similarly, I’d use potential concerns about carrageenan as additional motivation to avoid unhealthy foods like cream cheese, but I wouldn’t cut out healthful foods until we know more. I would, however, suggest that those with inflammatory bowel syndrome or other gastrointestinal problems try cutting out carrageenan at least temporarily to see if symptoms improve.

Titanium dioxide is another additive used in nondairy substitutes. See Titanium Dioxide & Inflammatory Bowel Disease for the latest on its safety.

Other videos on food additives include:

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image credit: cafemama / Flickr

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