Doug Powell

About Doug Powell

A former professor of food safety and the publisher of barfblog.com, Powell is passionate about food, has five daughters, and is an OK goaltender in pickup hockey. Download Doug’s CV here. Download C.V. »

Science of storytelling

Chapman and I have know for decades that when someone says they’re going to educate someone else about food safety stuff, it is doomed to failure.

The key to learning is, and always has been, storytelling.

Embed your data or facts within the story.

The Science of Storytelling (2019) shows you how to craft a compelling story using lessons from psychology and neuroscience. These blinks walk you through the steps of creating a narrative that grips your audience by subtly manipulating their brains. From demonstrating how to create a perfectly flawed character to explaining the power of stimulating details, Will Storr reveals the crucial elements that go into building a great story.

We’re all hosts on a viral planet: Phages to control Salmonella

Diets rich in minimally processed foods are associated with numerous health benefits, in part, due to their diverse, natural microbiota. However, antimicrobials, such as chlorine and peracetic acid (PAA), that are used to address food safety concerns may damage the natural microflora of fresh produce.

One promising approach for targeting pathogenic bacteria in foods without impacting the normal food microbiota are bacteriophages. In this study, we observed that combinational treatment of conventional antimicrobials (PAA and chlorine) and bacteriophages, specifically the Salmonella‐targeted preparation SalmoFresh, retained the bactericidal effectiveness of individual interventions, and in some cases, achieved substantially increased efficacy. Additionally, the bacterial microbiomes of farm fresh and organic produce were less affected after phage treatment compared to PAA and chlorine.

Finally, our study revealed that resistance rates against SalmoFresh were relatively minor and unaffected by the stresses introduced after chemical washes and/or bacteriophage treatment.

Treatment of fresh produce with a salmonella-targeted bacteriophage cocktail is compatible with chlorine or peracetic acid and more consistently preserves the microbial community on produce, 10 January 2020

Journal of Food Safety

Zachary D. Moye, Chythanya Rajanna Das, Jeffrey I. Tokman, Brian Fanelli, Hiren Karathia, Nur A. Hasan, Patrick J. Marek, Andre G. Senecal, Alexander Sulakvelidze

https://doi.org/10.1111/jfs.12763

https://onlinelibrary.wiley.com/doi/abs/10.1111/jfs.12763?af=R

E. coli persisters

Escherichia coli O157:H7 (EcO157) infections have been recurrently associated with produce. The physiological state of EcO157 cells surviving the many stresses encountered on plants is poorly understood. EcO157 populations on plants in the field generally follow a biphasic decay in which small subpopulations survive over longer periods of time. We hypothesized that these subpopulations include persister cells, known as cells in a transient dormant state that arise through phenotypic variation in a clonal population.

Using three experimental regimes (with growing, stationary at carrying capacity, and decaying populations), we measured the persister cell fractions in culturable EcO157 populations after inoculation onto lettuce plants in the laboratory. The greatest average persister cell fractions on the leaves within each regime were 0.015, 0.095, and 0.221%, respectively. The declining EcO157 populations on plants incubated under dry conditions showed the largest increase in the persister fraction (46.9-fold). Differential equation models were built to describe the average temporal dynamics of EcO157 normal and persister cell populations after inoculation onto plants maintained under low relative humidity, resulting in switch rates from a normal cell to a persister cell of 7.7 × 10−6 to 2.8 × 10−5 h−1. Applying our model equations from the decay regime, we estimated model parameters for four published field trials of EcO157 survival on lettuce and obtained switch rates similar to those obtained in our study. Hence, our model has relevance to the survival of this human pathogen on lettuce plants in the field. Given the low metabolic state of persister cells, which may protect them from sanitization treatments, these cells are important to consider in the microbial decontamination of produce.

IMPORTANCE Despite causing outbreaks of foodborne illness linked to lettuce consumption, E. coli O157:H7 (EcO157) declines rapidly when applied onto plants in the field, and few cells survive over prolonged periods of time. We hypothesized that these cells are persisters, which are in a dormant state and which arise naturally in bacterial populations. When lettuce plants were inoculated with EcO157 in the laboratory, the greatest persister fraction in the population was observed during population decline on dry leaf surfaces. Using mathematical modeling, we calculated the switch rate from an EcO157 normal to persister cell on dry lettuce plants based on our laboratory data. The model was applied to published studies in which lettuce was inoculated with EcO157 in the field, and switch rates similar to those obtained in our study were obtained. Our results contribute important new knowledge about the physiology of this virulent pathogen on plants to be considered to enhance produce safety.

Formation of Escherichia coli O157:H7 persister cells in the lettuce phyllosphere and application of differential equation models to predict their prevalence on lettuce plants in the field

08 November 2019

Applied and Environmental Microbiology

Daniel S. Munther, Michelle Q. Carter, Claude V. Aldric, Renata Ivanek, Maria T. Brandl

DOI: 10.1128/AEM.01602-19

https://aem.asm.org/content/86/2/e01602-19.abstract?etoc

Microbial contamination of grocery shopping trolleys and baskets in west Texas, 2020

The objective of this study was to identify food safety risk factors associated with supermarket trolleys (grills and handles) and handheld baskets. 

Indicator microorganisms evaluated were those detected by aerobic plate count (APC), yeast and molds (YM), Enterobacteriaceae (EB). Environmental listeria (EL), coliforms (CF), and E. coli (EC).  In addition, listeria monocytogenes, staphylococcus aureus, Escherichia coli O157 and salmonella sp. Were tested for.  Trolley grills (n=36) had 2.7 x 102 CFU/cm2.  Trolley handles (n=36) had 2.7 x 106 of CF and 5.2 CFU/cm2 of YM.  The bottom of handheld baskets (n=25) had 3.5 x 105 CFU/cm2 of CF and 5.07 CFU/cm2 of EC.  S. aureus was found on 96% of the baskets, 50% of the trolley handles (18 out of 36 samples), and 42% of the trolleys’ grills.  E. coli O157 was identified on 17% of baskets, 3% on trolley grills, and 3% on handles.  Salmonella sp. was detected on 16% of baskets and 8% of trolley grills.  L. monocytogenes was detected on 17% of the bottoms of handheld baskets but on none of the other samples. 

These results suggest the need for implementation of sanitation programs to regularly clean trolleys and baskets, as well as for consumer education. 

Microbial contamination of grocery shopping trolleys and baskets in west Texas, 2020

Food Protection Trends vol. 40 no. 1

Alexandra Calle, Breyan Montoya, Andrea English, and Mindy Brashears

https://www.nxtbook.com/nxtbooks/trilix/fpt_20200102/index.php#/10

Wiping out scrapie in goats, the genetic way

More consumers are developing a taste for goat cheese, milk, and meat as they become aware of the high protein and great taste of these products. While U.S. goat producers are enjoying this steady trend, they remain focused on keeping their animals healthy, especially from scrapie—a fatal brain disease that affects goats and sheep.

“The goat industry is one of the fastest growing animal industries in agriculture,” says Stephen White, an Agricultural Research Service (ARS) geneticist. “Not too many years ago, there were only a few hundred thousand goats in the country.” But in January 2018, goats and kids totaled 2.62 million head.

Meat and dairy are the biggest markets, followed by mohair, but goats serve in other unique capacities, says ARS veterinary medical officer David Schneider. Goats are being used to manage weedy areas along highways, get rid of kudzu in the Southeast, and even mow lawns. They’re also used as pack animals to carry supplies through rugged areas.

For any of these businesses, a single outbreak of scrapie could be devastating.

There is no cure or treatment for scrapie, which is in the same family—transmissible spongiform encephalopathies (TSEs) or prion diseases—as mad cow disease. TSEs are rare degenerative brain disorders characterized by tiny holes that give the brain a “spongy” appearance.

Most often scrapie is transmitted through birth fluids to other goats and sheep, and it can remain infectious in the environment for many years. It was first recognized in sheep in Great Britain and other European countries more than 250 years ago and was first diagnosed in U.S. sheep in 1947 in a Michigan flock.

All animals that get scrapie die. But there is good news from ARS. White and Schneider, who both work at ARS’s Animal Disease Research Unit in Pullman, Washington, are the first to demonstrate by infectious disease challenge that goats with the S146 allele (a different form of a gene) are less susceptible to scrapie over a usual goat lifetime. They also tested the K222 allele in goats. Their research shows that goats with one copy of either the S146 or K222 allele did not develop scrapie after being challenged with infection at birth. The study was published in The Veterinary Journal in 2018.

“Commercial goats raised for either meat or milk age out of herd participation as milkers, dams of commercial offspring, or as sires by around 6 years of age,” White says. In this ongoing ARS research, goats with the resistance alleles have lived beyond this commercial lifetime—up to 7½ years—with no clinical disease and without getting sick.

The only countries considered to be scrapie free are Australia and New Zealand. Currently, if one goat is diagnosed with scrapie on a U.S. farm, all goats are quarantined for life or euthanized. “You couldn’t restock your operation with any susceptible animal,” White says. “The farmer’s operation would be over.”

This research is good news for both goat and sheep producers because it could help with eradication efforts. Before U.S. producers can take advantage of import and export markets, scrapie must be eradicated from the United States and meet the World Organisation for Animal Health (OIE) criteria for disease freedom.

Origins of mad cow disease

Aristos Georgiou of News Week reports an international team of scientists has said that they may have identified the origin of mad cow disease. Known as bovine spongiform encephalopathy, the neurodegenerative disease destroys the brain and spinal cord in cattle, causing death.

Since BSE first appeared in the 1980s in the United Kingdom, scientists have tried to identify how the disease emerged, however, no one hypothesis has been confirmed.

For a study published in the journal Proceedings of the National Academy of Sciences, the team of scientists investigated the origins of BSE by injecting a particular variant of scrapie disease into mice which have been genetically modified with bovine DNA.

The researchers say that, unexpectedly, the injection of the scrapie strain into the genetically modified mice resulted in the propagation of classical mad cow disease prions. These prions are present in natural form in the scrapie variant.

This observation indicates that the illness could be transmitted between different species and that the modified mice could develop mad cow disease, according to the study.

Olivier Andreoletti, an author of the paper from the French National Institute for Agronomic Research (INRA,) told AFP that the modified mice are “a very good model, which works well in terms of knowing what would happen if one exposed cows to those prions.”

He noted that the results provide, for the first time, and “experimentally underpinned explanation” for the appearance of mad cow disease in the U.K. in the 1980s.

After emerging, the disease spread in cattle across Europe, North America and other regions of the globe. This process was exacerbated by the fact that cows were being given feed which contained tissue from other cows infected with the disease.

They still suck: After years of bashing agriculture and GMOs, Chipotle reverses course

I started bashing Chipotle about 2006, when driving through Kansas City with a trailer full of stuff as I moved to Manhattan, Kansas, to follow a girl, and cited this billboard.

Any company focused on this stuff usually meant they were somewhat oblivios to basic food safety.

Unfortunately for all the thousands of sick people over the next 14 years, I was right.

I tried to call them out for the food safety amateurs they were.

Even worse, when Amy was pregnant with Sorenne, she would get Chipotle cravings and I would dutifully comply, because she was doing the heavy lifting in pregnancy.

Now I have an entire book chapter I’m working on, devoted to Chipotle.

Kevin Folta of the Genetic Literacy Project writes that after years of attacking conventional agriculture and crop biotechnology, Chipotle now seems to have found a love for the American farmer that is as warm and inviting as the gooey core of a steak burrito. With the launch of its “Cultivate the Future of Farming” campaign, the company seeks to raise awareness about the hardships facing American agriculture and offer some recommendations and seed grants to address the problems. According to the campaign website:

It’s time to take real steps to give the next generation of farmers a bright future. Through our purpose to Cultivate a Better World, we’re putting programs in place that make a real impact, including seed grants, education and scholarships, and 3-year contracts. Our vision is bold, but we’re starting with a mission to cultivate the future of farming by focusing on pork, beef, and dairy.

It is good to see a company raising awareness about these issues. But given Chipotle’s past cozy relationship with organic food marketers, this seems more like a marketing stunt to woo consumers who are growing increasingly concerned about the status of American farms, and less like a genuine example of philanthropy.

Chipotle is absolutely correct about one thing. The crisis in agriculture is real. Farmers are facing low prices for their products, astronomical costs, and strangling regulation.  Farms, from commodity crops to dairies, are going out of business daily. Farmer suicides are a barometer of how severe the problem is.

From Chipotle’s website- The “challenge is real” and “It’s a hard living.”

However, Chipotle’s new ag-vertisment seems too little, too late. The threats to farmers and the public’s negative perception of agriculture didn’t seem to bother the company just a few years ago. For example, it’s 2014 video Farmed and Dangerous was an assault on large-scale animal agriculture, the industry that produces the ingredients that go into Chipotle’s burritos. Farmed and Dangerous was not the restaurant chain’s first effort, either.  The video short The Scarecrow falsely depicted a sad, dystopian world of dairy production in which forlorn cows are locked in stacked metal boxes as milk is extracted by an extensive network of plumbing.

And of course, Chipotle’s penetrating campaign against genetic engineering (GE) sought to capitalize on the momentum of several failed GMO labeling efforts, which were designed to demonize crop biotechnology by suggesting to consumers that GE seeds were dangerous—an allegation known to be false.

Let’s get real. Chipotle’s decisions to criticize agriculture and then embrace it were not born of altruism.  Public-facing corporate positions are spawned from focus groups and surveys. As a multinational, billion-dollar food empire, Chipotle is no different. The company’s ad campaigns aim to reinforce consumers’ perceptions and identity, showing that Big Burrito shares their values. That is what we see in this latest pro-farm campaign. The public is becoming increasingly aware of the fragile state of US agriculture and the crisis that has hit rural North America hard, and Chipotle is responding.

So is “Cultivate the Future of Farming” just an ag-washing ornament to exploit farmer hardship, or is this a genuine change of heart?

If it is indeed the latter, it needs to start with an apology—an honest one. Chipotle needs to publicly reject its anti-science positions and profound misrepresentation of agriculture. In the six years since the fast food chain’s anti-farming efforts hit a feverish pace, public perception has changed. The fear-based misinformation campaigns are failing, and time has not treated such efforts well. Chipotle’s videos are a shameful reminder of the rhetoric that was so prevalent just a short time ago.

Imagine where we’d be today if in 2014 Chipotle and other brands  invested heavily in research, rural mental health, or resources to bring precision agriculture to farmers. I think the perception of Chipotle and the perception of crop and animal production would be very different.

Perhaps the most important takeaway is that you shouldn’t bite the hand that feeds in the first place. Targeting farmers who produce the products you sell is bad business—and it threatens a critical industry we all depend on.

Where does it come from? Salmonella in macadamia nuts in Queensland

Salmonella enterica is a common contaminant of macadamia nut kernels in the subtropical state of Queensland (QLD), Australia. We hypothesized that nonhuman sources in the plantation environment contaminate macadamia nuts.

We applied a modified Hald source attribution model to attribute Salmonella serovars and phage types detected on macadamia nuts from 1998 to 2017 to specific animal and environmental sources. Potential sources were represented by Salmonella types isolated from avian, companion animal, biosolids-soil-compost, equine, porcine, poultry, reptile, ruminant, and wildlife samples by the QLD Health reference laboratory. Two attribution models were applied: model 1 merged data across 1998–2017, whereas model 2 pooled data into 5-year time intervals. Model 1 attributed 47% (credible interval, CrI: 33.6–60.8) of all Salmonella detections on macadamia nuts to biosolids-soil-compost. Wildlife and companion animals were found to be the second and third most important contamination sources, respectively. Results from model 2 showed that the importance of the different sources varied between the different time periods; for example, Salmonella contamination from biosolids-soil-compost varied from 4.4% (CrI: 0.2–11.7) in 1998–2002 to 19.3% (CrI: 4.6–39.4) in 2003–2007, and the proportion attributed to poultry varied from 4.8% (CrI: 1–11) in 2008–2012 to 24% (CrI: 11.3–40.7) in 2013–2017.

Findings suggest that macadamia nuts were contaminated by direct transmission from animals with access to the plantations (e.g., wildlife and companion animals) or from indirect transmission from animal reservoirs through biosolids-soil-compost. The findings from this study can be used to guide environmental and wildlife sampling and analysis to further investigate routes of Salmonella contamination of macadamia nuts and propose control options to reduce potential risk of human salmonellosis.

Source attribution of salmonella in macadamia nuts to animal and environmental reservoirs in Queensland, Australia,

04 December 2019

Foodborne Pathogens and Disease

Nanna MunckJames SmithJohn BatesKathryn GlassTine Hald, and Martyn D. Kirk

https://doi.org/10.1089/fpd.2019.2706

https://www.liebertpub.com/doi/10.1089/fpd.2019.2706?utm_source=sfmc&utm_medium=email&utm_campaign=FPD%20OA%20Dec%206%202019&d=12/6/2019&mcid=386543234

White Castle frozen food division announces voluntary recall of a limited production of frozen sandwiches due to Listeria monocytogenes

Any excuse to write about White Castle means I get to recall the great movie, Harold and Kumar Go To White Castle.

I had a hockey friend over for lunch one day, we ate steak and watched Harold and Kumar, and it was one of the best times ever.

White Castle has initiated a voluntary recall of a limited number of frozen 6 pack cheeseburgers, frozen 6 pack hamburgers, frozen 6 pack jalapeno cheeseburgers, and 16 pack hamburgers, 16 pack cheeseburgers for the possible presence of Listeria monocytogenes. 

The voluntary recall will impact product on shelves at select retailers with best by dates ranging from 04 Aug 2020 to 17 Aug 2020. Any product with these dates on shelves is presently being removed. Any product with a best by date before or after these best by dates is not included in the voluntary recall.

To date, public health officials have not reported any illness associated with these products.

“Our number one focus is the safety of our customers and our team members, and as a family owned business, we want to hold ourselves to the absolute highest standards of accountability in all aspects of our business – and especially food safety,” said White Castle Vice President, Jamie Richardson.

Uh huh.

‘No biggie’: 11 gastro cases at Australian aged care home

An aged care home criticised for its handling of an influenza outbreak which killed 10 people has suffered a gastro outbreak.

A staff member, who asked to remain anonymous, raised concerns about the way the situation had been handled.

A Department of Health and Human Services spokesman said the first case was identified last Thursday with eight residents and three staff affected, with the department notified on Tuesday (that in early Dec.).

Respect Aged Care chief operating officer Brett Menzie said it wasn’t a major outbreak.

The dates and number of infected people differed to those provided to DHHS, with Mr Menzie stating five residents and three staff members were infected.

Mr McKenzie said a resident first showed signs of gastro on Sunday, with an outbreak – which occurs when three people show symptoms – declared on Monday.

He said the Health Department had been notified and infection control procedures enacted.

“St John’s Retirement Village Nursing Home did not implement a coordinated and timely infection control program that was effective in identifying and containing infection during the influenza and respiratory outbreak of August and September 2017,” a report found.