Issue #48 2022-07-25
What female food scientists get paid 😞, mystery tara flour - how did it cause the Daily Harvest outbreak? Solving Listeria outbreaks with NGS, And emerging concerns in food safety
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Cold Case Solved - What You Should Know About NGS
Pay Disparity in Food Science Careers 😞
The Daily Harvest Outbreak Mystery: Still Not Solved, But Progress Has Been Made
Emerging Food Safety Issues: Here’s What Dutch Experts Are Thinking About – And We Should Be Too
Food fraud incidents and horizon scanning updates from the past week
🎧 On the go? Listen to me read out today’s email. Get access to audio with a free trial subscription, at the bottom of this email 🎧
How do we keep food hazards out of food if we don’t know what the hazards are? That’s the big question this week.
Welcome to Issue 48 of The Rotten Apple: four short, expertly-curated stories about food safety and food fraud that you need to know about. Without the boring bits.
In this issue, I explain what NGS is and why you need to know about it. And I share two stories that address this week’s big question: how can we protect consumers from food hazards that we don’t know about? There’s an update on the mystery hazard in the Daily Harvest outbreak in the USA, plus a list of emerging hazards that are on the radars of Dutch experts, including one that is pretty weird.
Also this week, you’ll find food scientist salary numbers that made me sad. And as always, food fraud incidents from the past week.
Have a lovely week (and stay cool, if you’re in the northern hemisphere, sheesh!).
Karen
P.S. If you know someone who would benefit from this newsletter, please share it.
Cover image: Christina @ wocintechchat.com on Unsplash
Food Safety
Cold Case Solved + What You Should Know About The New(ish) Tool NGS
NGS – next generation sequencing – is a cheap(er) and fast(er) way to catalogue the entire genome of an animal, plant or microorganism. Although it has been possible to discover the DNA and RNA sequences of organisms for decades, it used to be prohibitively expensive.
NGS methods are much cheaper than older technologies, and this means that it is now practical to use DNA and RNA sequencing to discover which strains of a pathogen are responsible for illnesses.
“The human genome took almost 13 years [to sequence in the 1990s], at a cost greater than $1 million, whereas now, it is possible to sequence the human genome within a week at the cost of $100.” Sandhya Verma, Rajesh Kumar Gazara, in Translational Bioinformatics in Healthcare and Medicine, 2021
When a foodborne illness outbreak occurs, investigators attempt to link contaminated food with samples from sick people. They look for similarities between the organisms in the food and in the blood or stool samples of the victims.
They don’t just look for species-level similarities, but for “strains” of the microorganism.
For example, Listeria monocytogenes is a species of bacteria, one of 17(ish) species that belong to the genus Listeria. Among the 17(ish) species of Listeria, only two are known to be pathogenic, including the deadly foodborne pathogen L. monocytogenes.
At the species level there is quite a lot of variation. For example, L. monocytogenes has at least 14 known strains. Think of a strain (more properly called a serotype) as you would a breed of dog. All dogs are the same species, but dalmatians are different to chihuahuas.
Identifying the strain of a pathogen allows for better tracking of infection sources. For example, if you find the same strain of L. monocytogenes in a food factory and a sick person, you have got yourself more of a “smoking gun” in epidemiological terms than finding unrelated strains.
Until recently, if you wanted to find the strain of a bacterium, you had to perform a series of chemical tests on a bacterial culture growing on agar plates. Different strains respond to different chemicals and dyes differently, and so the results of a series of chemical tests were needed to identify a strain with confidence.
With NGS you can accurately match bacterial strains in food, factories and patient pathology samples quickly and with a high degree of confidence. And at a reasonable cost.
The power of NGS
A mysterious series of sporadic listeriosis illnesses was solved using NGS this year. The illness had been appearing in Bavaria, Germany, for years. More than a dozen people had become seriously ill and one person had died.
Epidemiologists had not been able to determine the source of the illnesses, because it was difficult to know which foods all the victims might all have eaten. Listeriosis has a long incubation period. It averages twenty-one days and can be as long as seventy days. Imagine trying to recall every food you had eaten in the past seventy days!
Then, in 2020, researchers who were checking historical Listeria samples from previously sick patients discovered a link between thirteen patients. The patients were all from Bavaria and had all been sick with listeriosis in the past decade. The researchers were using NGS to examine the genetic sequence of the bacteria. They found almost identical genomes in these linked patients, which means the bacteria came from the same source.
This detailed information about the exact serotype of the pathogen allowed Bavarian food safety officials to discover the probable source of all thirteen illnesses. They detected an exact match of the bacterium at a food company that was supplying canteens and care homes with fruit and vegetable products. This exact match genetic sequence was the “smoking gun” that linked the produce company to the illnesses and death.
Takeaways
NGS technology makes it easier for investigators to pinpoint the source of foodborne illness outbreaks, including old “cold cases” and cases that might not initially appear to be linked. This makes it more probable that food companies will be caught if they supply contaminated food.
In short: 🍏 NGS is next generation sequencing 🍏 NGS is a cost effective way to sequence the genomes of food pathogens 🍏 Researchers used NGS to sequence Listeria monocytogenes strains from patients in Bavaria, Germany 🍏 There had been a number of listeriosis cases in Bavaria for which a source had not been found using traditional methods 🍏 NGS allowed investigators to match the genetic sequence in patients and environmental samples from a produce company 🍏 NGS makes it easier for investigators to link food companies with illnesses, compared to traditional microbiological methods 🍏
Sources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4875933/
https://www.frontiersin.org/articles/10.3389/fmicb.2021.792162/
https://www.foodsafetynews.com/2022/07/source-of-7-year-listeria-outbreak-found-in-germany/
Food Industry Careers
Pay Disparity in Food Science Careers 😞
According to the IFT (Institute of Food Technologists, a US-based association with global membership), when it comes to food science careers, women’s median salaries are just 70% of men’s median salaries. Holey moley. The median salary for black employees is 91% of the median for white employees.
Disturbingly, the news release that shared this information went on to blame women for the pay gap. A recruitment agent from an executive search company was quoted as saying that women don’t ask for more money, while men do.
The results were collected by the IFT, for their 2022 Compensation and Career Path Survey. Full results have not been published yet, but are due in the next few months.
🍏 https://foodindustryexecutive.com/2022/07/dispatches-from-ift-first-workforce-innovation-and-more/ 🍏
Food Safety
The Daily Harvest Outbreak Mystery: Still Not Solved, But Progress Has Been Made
Daily Harvest, the direct-to-consumer food company whose consumers were hospitalised with severe abdominal pain and liver failure in May and June has published an update. They think it’s the tara flour. But they don’t know how the tara flour made people sick.
Why care?
We still don’t know what the toxin is. As a food safety specialist, it’s hard to do your job of protecting consumers from hazards if you don’t know what those hazards are.
Background
The company’s lentil crumbles, a meal-topper, were recalled after hundreds of reports of illnesses. Extensive testing, by at least three independent labs, and the US FDA, failed to find the cause of the illnesses.
The testing ruled out all major bacterial pathogens, common human food allergens, foodborne viruses, aflatoxins, amatoxins and mycotoxins.
I wrote about this mysterious and serious foodborne outbreak in Issue #44 and Issue #46. In the last two weeks, the official number of reported cases has more than doubled, with the FDA now listing 277 “adverse events” and 96 hospitalisations.
The suspected cause is…
Daily Harvest says the ingredient that caused the illnesses is tara flour. Great. But they don’t actually know what was in the tara flour that could have caused such severe illness. Not great.
“Our team will continue working with the FDA, the tara flour producer and others to help determine what specifically made people sick.” Daily Harvest’s CEO
Is tara flour unsafe per se, or was there something unexpected in that batch? In my research for Issue #46, I found zero peer-reviewed studies on tara flour or its safety for use in food. Tara gum is an approved food additive (E417) but is a carbohydrate-containing material and probably comes from a different part of the tara tree than the “flour” which is marketed as a protein-rich ingredient.
What now?
Once we know what was in the flour that made people sick we will, as a food safety community, update our lists of known hazards in tara flour and related plant-based foods. And then we will review our food safety protocols to address those hazards so we can make sure that this never happens again.
But for now, we wait. Our thoughts are with the food testing experts who are examining the tara flour. And with the consumers who are battling with the long-term effects of their illnesses. 🍏
Sources:
https://www.daily-harvest.com/content/french-lentil-leek-crumbles-advisory#
Food Safety
Emerging Hazards: Here’s What Dutch Experts Are Thinking About – And We Should Be Too
Emerging food safety issues have been reported by a Dutch network of government experts and academic professionals. Here’s a list of emerging risks that they think we should be controlling better or learning more about:
Foodborne parasites such as Echinococcus multicolaris, Toxoplasma gondii, E. granulosis, Trichinella and Cryptosporidium;
Potential new risks from minimally processed and low salt foods and from new or becoming-more-popular cooking techniques such as sous vide and slow cooking;
Heads up: I’ll be publishing a special supplement on the food safety aspects of sous vide for paying subscribers next month
Risks to humans from raw pet foods;
Rat meat being sold for human or animal food;
Group B Streptococcus (Check out Issue #17 for a short description of Group B Strep and why it’s an emerging food safety hazard);
Staphylococcus saprophyticus in pork meat and possible links with human urinary tract infections;
Dietary supplements with medical claims (last week’s issue had reports about fraudulent honey supplements for erectile dysfunction that contained undeclared sildenafil (=Viagara))
The presence of persistent environmental pollutants such as polycyclic aromatic hydrocarbons and bromodioxins in CBD (cannabidiol) oil and in eggs;
Mycotoxins in the context of changing climatic conditions;
Hazards posed by eating and selling wild mushrooms;
COVID-19 pandemic’s impact on food fraud; and
Recycled plastics in food contact packaging.
🍏 The report: https://www.rivm.nl/bibliotheek/rapporten/2022-0054.pdf 🍏
My main source for this story, because I don’t speak Dutch 😉, was the marvellous Joe Whitworth, writing in Food Safety News, thanks, Joe!
What you missed in last week’s email
· Surprising Seafood fraud: the stats are in and they were unexpected
· Human drugs in pork and poultry, an unusual food fraud
· Vegan food - a legal definition
· What exactly is Life cycle Assessment (LCA)?
Below for paying subscribers: Food fraud incident reports, horizon scanning updates, plus an awesome audio version with a real live human voice - mine … Check out an example to see how the email looks (and sounds) for paying subscribers here.
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