Misinformation and selective coverage change perception of outbreaks, but can be corrected by presenting the facts

While it’s not an animal product, the Listeriosis outbreak recently traced to apples is just as relevant to the food industry as a whole as any other food-borne illness outbreak. While I was looking for more information on the outbreak, I came across this gem* of an article posted on cnn.com.

*When this post was originally written, the text on the website read: “At least seven people have died after eating caramel apples that may have been infected with Listeria monocytogenes. Followed immediately by a quote from CDC which stated ‘Thirty-one ill people have been hospitalized and six deaths have been reported. Listeriosis contributed to three of these deaths, and it is unclear whether it contributed to an additional two deaths. The sixth death was unrelated to listeriosis.'” CNN has since removed the CDC quote, but kept their original ‘7 deaths’ statement.”

I found this disturbing on two levels. First, the fact that they reported that at least six people had died after eating contaminated apples, when listeriosis was only confirmed as cause of death for 3 of the cases and ruled out for the 6th.

“Hey Jen, what’s the body count up to on that outbreak article?”

“Looks like 3 for sure, could be 3-5”

“Thats it?”

“Don’t worry, we’ll round up to 6+, if you use a Log scale, they’re practically the same number.”

Second, they used the direct quote from CDC’s 12/31 update to directly contradict themselves in the following sentence. Who wrote this article? (update, clearly they wizened up and removed the quote on Jan 15, I wonder if they saw the reddit post. This is also a rhetorical question, their name is on the article, but we also need to assign blame to their editor.).

So what sort of impact could this statement have? Young, Norman, and Humphries reviewed the impact of media coverage on how dangerous we think they are. They found that indeed, those conditions/diseases that receive more media coverage are perceived by medical students as a “worse” condition. This can actually be a very good thing for infectious disease outbreaks, as rapid media coverage of the danger encourages people to avoid contact with others, leading to exponentially fewer cases the earlier you do it. This is less good however, when non-infectious diseases or inaccurate correlations are blown out of proportion (e.g. people avoiding pork to avoid H1N1).

The literature review included in the beginning of the article shows that this isn’t necessarily new information. However, the authors also examined the effect or including additional “objective” information about the conditions when asking students to rank their risk. The result was that, as seen in the chart below, when provided additional information the study participants then changed their views of the diseases. The large separation between what they had seen in media and what they had not seen shrank and they assigned more risk to those threats that aren’t often talked about, and became less nervous of the high coverage items in comparison.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0003552As a science blogger, this is my soapbox, as this study highlighted the responsibility for those who know more than the headline to speak up and share their knowledge, because people can and will be receptive to it as long as it’s available.

Unfortunately, the study was inherently biased as medical students are more likely to be receptive to new data (especially related to disease) as opposed to other groups with stronger existing bias’ (e.g. CAM users, anti-vaccination proponents, specialist doctors, or epidemiologists who may be swayed by previous outbreak coverage). The authors specifically did not survey students on their current media usage or biases, and therefore could not demonstrate the power of providing additional information on subjects they may have already formed strong opinions on.

I’d like to see the study repeated with an older group, as student’s opinions are more likely to be malleable as they are less likely to know as much about these illnesses or had personal experiences with them. A repeated study with participants of at least 40-years-old would be more telling and help us understand what effect providing additional objective information can have.

After all, as nice as it is to know students can be taught, they’re not the ones in public office. Are they also willing to change their minds when new information is made available?
Young ME, Norman GR, & Humphreys KR (2008). Medicine in the popular press: the influence of the media on perceptions of disease. PloS one, 3 (10) PMID: 18958167

Mummert A, & Weiss H (2013). Get the news out loudly and quickly: the influence of the media on limiting emerging infectious disease outbreaks. PloS one, 8 (8) PMID: 23990974ResearchBlogging.org

Why isn’t the USDA declaring the invisible feces in our meat?

No, that wasn’t a typo. Today I came across this petition for rulemaking to FSIS from the Physicians Committee for Responsible Medicine.

First off: PCRM has some great programs that promote research, animal welfare, and better medicine. The overall merit of their organization cannot be judged by a single program or campaign they have in place.

Now let’s tear this petition apart, because I actually had to check their website to make sure it was real, and not an over-the-top satire from The Onion.

The concern the committee wishes to correct via this petition is thus:

“Inconsistent with its statutory mandate, USDA regularly passes at inspection meat and poultry that is  contaminated with feces. Although USDA implements a “zero tolerance” policy for fecal contamination, this policy applies to visible fecal contamination only. The result is that fecally contaminated meat and poultry products pass inspection as long as the feces on them are not “visible” to the naked eye.

This inspection policy conveys a misleading promise of “wholesomeness.” Feces may contain round worms, hair worms, tape worms, and leftover bits of whatever the animal excreting the feces may have eaten, not to mention the usual fecal components of digestive juices and various chemicals that the animal was in the process of excreting. Americans deserve fair notice that food products deemed “wholesome” by USDA would be deemed disgusting by the average consumer and adulterated under any reasonable reading of federal law.”

Not to quote without context, the petition goes on to list the ways in which non-obvious feces may be introduced to meat product, the most valid being shared scald/chill tanks in processing operations.

Ultimately, the corrections the committee is seeking are removal of the “wholesome” description from USDA inspected meats, begin treating feces as an adulterant, and:

“USDA should amend sections 317.2(l)(2) and 381.125(b)(2)(i) of the Code of Federal Regulations to exclude from the current mandatory label the sentence that reads, “This product was prepared from inspected and passed meat
and/or poultry.” USDA should amend sections 317.2(l)(2), 381.125(b)(2)(i), and 381.125(b)(2)(ii) of Title 9 to include in the mandatory label the following as the second-to-last sentence: “This product may be permeated with feces, which cooking does not remove.”

That’s some pretty heavy language, perfectly stated to play on the fears and squeamishness of your average consumer. However, I see nothing written there about food safety, so the intention of the change is obvious: prevent people from eating meat.

While the about page for PCRM mentions nothing about being proponents of animal rights, the amount of articles devoted to encouraging a purely vegan diet clearly shows that they have an anti-meat agenda. While they correctly advertize the health benefits of vegan foods, a quick search of their website saturates any visitor with the message “meat is bad, and animal agriculture is always cruel”.

The petition shines a light on a group that is ready to intentionally scare and mislead consumers into changing their lifestyle. As part of their justification that feces is everywhere, they cite one of their own studies, “Fecal Contamination in Retail Chicken Products“. In this study, the committee proved that invisible fecal contamination is everywhere by “testing for the presence of feces.”

No such test exists.

What they actually did was test for generic E. coli, which can act as an indicator organism for fecal contamination.  HACCP programs in slaughter facilities use on-line enumeration of E. coli and other coliforms to validate critical control points for just that purpose. But in this case, rather than setting limits and using a statistical rationale to make a conclusion about the level of contamination, it appears that any evidence of the presence of E. coli  led to the determination that the sample was contaminated with feces. Because there are no methods declared, this evidence could be as mundane as RNA fragments from a non-pathogenic strain recovered in an enriched sample.

The study is absolutely meaningless. There is no available data to review in terms of the levels of contamination, no methods listed for how the E. coli was enumerated, and finally no legitimate publication, suggesting that the construction of the study and its conclusions would not have passed peer review.

As part of the rule change, PCRM would like feces to be declared as an adulterant. Generally, USDA inspectors cannot allow adulterated products to enter commerce, adding to the ludicrosity of this proposal. By the PCRM’s definition, all meat products are covered in invisible feces, and the presence of invisible feces should prevent any product from entering commerce. In one swift move, PCRM will ensure that only clean, wholesome meats will be sold, i.e. none.

But have things changed over the years to make eating meat less safe? The PCRM thinks so. I have no data to argue whether or not Americans are cooking less (PCRM also neglected to provide data), and eating more RTE products, but I did think it was funny that when I read this:

“Americans today consume far more meat and poultry than ever before, thereby increasing their potential exposure to fecal contamination in these products”

When the first link I read on their website contained this graph…
http://www.pcrm.org/media/blog/nov2013/youre-in-good-company-with-a-vegan-thanksgiving
http://www.pcrm.org/media/blog/nov2013/youre-in-good-company-with-a-vegan-thanksgiving
Which is it PCRM? Whichever is more convenient for the ad campaign at the time?
(side note: if people indeed are eating out more in restaurants, that would mean they are eating at inspected restaurants where county health inspectors ensure adequate cooking temperatures, rather than at home where people rarely if ever have proper process control)

Finally, the idea that the USDA needs to declare the presence of invisible feces on every product that passes inspection makes no logical sense,  and does nothing but mislead the consumer, not only by implying that the product isn’t safe in general, but that fully cooking the product makes no difference. If it wasn’t obvious by now that this proposed rule change isn’t solely to earn points with vegans, look closely the wording. In order to turn consumers off meat, PCRM would risk undoing years of public education and trust in proper cooking temperatures.

Clearly I took this proposal too literally, but because FSIS will actually have to review the proposal, and PCRM wants to brag about how these changes might occur, I offer one last piece of evidence to support my view that this proposal belongs on a tabloid.
Proposed legends

…one of their proposed inspection marks literally contains a DO NOT EAT symbol.

ResearchBlogging.org

Physicians Committee for Responsible Medicine (2013). Re: Fecal Contamination of Poultry and Meat USDA Petition for Rulemaking

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The poultry microbiome, once again proving that culture-based ecology misleads us all

Shigella penetrating the intestinal wall. Source: cellimagelibrary.org

If the world was enriched and homogenized, we would actually have a very good idea of what the microbiological community within looks like. Fortunately, the world is much more complex than the miniature environments we culture in the lab, and high throughput sequencing (HTS) is allowing us to fully appreciate micro-biodiversity. As new information becomes available, many of our models for microbial communities continue to be challenged by the actual composition of species in natural environments.

In the world of food safety, we rely on these models to set policy on a regulatory level, and to set critical limits down at the production level. Which tests we run on what products depend directly on what organisms (that cause food borne illness or spoilage) are supposed to be found on that type of food. The authors of this study that came out in PLOS ONE this February examined the microbiome associated with poultry products from farm to fork (meaning from clucking chicken to packaged poultry product) using HTS rather than culture/enrichment methods. The results indicate that there is an unappreciated amount of diversity between different stages of the poultry production process, and that we may not acknowledge the presence of some organisms as much as we should.

In the study, samples were taken from multiple steps in the poultry production process: wet and dry litter, fecal samples, fluid from carcasses collected during the cooling process following slaughter, and fluid from raw retail poultry products (legs, wings, and breasts). Other than the retail portion, all of the samples collected were from the same batch of birds from start to finish. The available RNA from viable cells in each sample was amplified and identified as belonging to specific species using a combination of Illumina sequencing and database referencing (blastn and usearch).

From this pile of data, lists of organisms were compiled to compare the ecosystem profile for each point in production.

The numbers refer the the number of unique taxa found in each group

The authors were very surprised by the amount of diversity between the two litter samples (wet and dry) and the fecal sample. They expected to see very similar profiles, as all of the predicted microbes in those groups would be inoculated from contact with fecal material (young chicks have no inherited microflora, and are coprophagous); however, all of the groups’ microbial communities had very little in common. As shown above, of the hundreds of unique species identified, only 52 were actually found at every stage from farm to fork.

In evaluating food safety, several results are of concern. The first was that the authors found significant amounts of Shigella spp., which have traditionally not been associated with poultry products and may not be a part of many sanitation programs. The second is that in one of their dry litter samples, the authors found a large amount of C. jejuni. It’s presence was interesting as previous studies have found it difficult to cultivate C. jejuni onto dry litter, suggesting that it will not grow in that environment. This discovery further shows that our attempts to cultivate bacteria are not indicative of their behavior in “the wild”. There may be nutrient gradients or a symbiont in play that allows C. jejuni to grow; therefore the possible contamination of dry litter has to be acknowledged in that facility’s Campylobacter monitoring program.

The last point of interest I’ll discuss here is the large amount of unique species that were found in samples following slaughter. This suggests that these species did not come from the farm, but rather were introduced during slaughter and processing. Interestingly, among Campylobacter spp., there was little to no abundance of C. jejuni in the samples, but differing amounts of other Campylobacter spp. This is revealing, as we have been predisposed to expect C. jejuni to be present due to our use of selective media.

Let’s fully appreciate the amount of diversity found within the processing facility, the authors collected two post-processing samples labeled carcass rinse and carcass weep. The rinse was composed of fluid shaken off of the carcass following its removal from the chlorinated chill tanks, and the weep was the drippings from the same carcass 48 hours later. 2/3 of the unique species found the weep samples were not found in the rinse. The authors interpret this as being due to the fact that the sterilization of carcasses is not the goal of poultry processing, and provide the example that viable Salmonella can be recovered from carcasses even after they are sent through the standard antimicrobial processes. The goal is to reduce enumeration, not sterilization.

Finally, in examining the retail samples, we get what we expect. Similar organisms as the weep, with some new faces, presumably because they persisted through processing at undetectable levels, and slowly grew as the product was stored in refrigeration.

The authors conclude by examining some potential symbionts that would allow C. jejuni to persist, but ultimately say that due to the high number of environments C. jejuni can occupy, attempting to exclude it in a universal way will not be very effective.

So all in all, a thorough example of the misdirection we receive from culture bias, and a startling look at how, given enough incubation time, properly processed meat can still support a huge amount of microbial diversity, including many food borne pathogens.

Appreciate this diversity, and make sure you cook your chicken to temperature.

 

ResearchBlogging.org

Oakley BB, Morales CA, Line J, Berrang ME, Meinersmann RJ, Tillman GE, Wise MG, Siragusa GR, Hiett KL, & Seal BS (2013). The Poultry-Associated Microbiome: Network Analysis and Farm-to-Fork Characterizations. PloS one, 8 (2) PMID: 23468931