A surprising weapon in the fight against food poisoning
Lina Zeldovich has written about science, medicine and technology for Popular Science, Smithsonian, National Geographic, Scientific American, Reader’s Digest, the New York Times and other major national and international publications. A Columbia J-School alumna, she has won several awards for her stories, including the ASJA Crisis Coverage Award for Covid reporting, and has been a contributing editor at Nautilus Magazine. In 2021, Zeldovich released her first book, The Other Dark Matter, published by the University of Chicago Press, about the science and business of turning waste into wealth and health. You can find her on http://linazeldovich.com/ and @linazeldovich.
Every year, one in seven people in America comes down with a foodborne illness, typically caused by a bacterial pathogen, including E.Coli, listeria, salmonella, or campylobacter. That adds up to 48 million people, of which 120,000 are hospitalized and 3000 die, according to the Centers for Disease Control. And the variety of foods that can be contaminated with bacterial pathogens is growing too. In the 20th century, E.Coli and listeria lurked primarily within meat. Now they find their way into lettuce, spinach, and other leafy greens, causing periodic consumer scares and product recalls. Onions are the most recent suspected culprit of a nationwide salmonella outbreak.
Some of these incidents are almost inevitable because of how Mother Nature works, explains Divya Jaroni, associate professor of animal and food sciences at Oklahoma State University. These common foodborne pathogens come from the cattle's intestines when the animals shed them in their manure—and then they get washed into rivers and lakes, especially in heavy rains. When this water is later used to irrigate produce farms, the bugs end up on salad greens. Plus, many small farms do both—herd cattle and grow produce.
"Unfortunately for us, these pathogens are part of the microflora of the cows' intestinal tract," Jaroni says. "Some farmers may have an acre or two of cattle pastures, and an acre of a produce farm nearby, so it's easy for this water to contaminate the crops."
Food producers and packagers fight bacteria by potent chemicals, with chlorine being the go-to disinfectant. Cattle carcasses, for example, are typically washed by chlorine solutions as the animals' intestines are removed. Leafy greens are bathed in water with added chlorine solutions. However, because the same "bath" can be used for multiple veggie batches and chlorine evaporates over time, the later rounds may not kill all of the bacteria, sparing some. The natural and organic producers avoid chlorine, substituting it with lactic acid, a more holistic sanitizer, but even with all these efforts, some pathogens survive, sickening consumers and causing food recalls. As we farm more animals and grow more produce, while also striving to use fewer chemicals and more organic growing methods, it will be harder to control bacteria's spread.
"It took us a long time to convince the FDA phages were safe and efficient alternatives. But we had worked with them to gather all the data they needed, and the FDA was very supportive in the end."
Luckily, bacteria have their own killers. Called bacteriophages, or phages for short, they are viruses that prey on bacteria only. Under the electron microscope, they look like fantasy spaceships, with oblong bodies, spider-like legs and long tails. Much smaller than a bacterium, phages pierce the microbes' cells with their tails, sneak in and begin multiplying inside, eventually bursting the microbes open—and then proceed to infect more of them.
The best part is that these phages are harmless to humans. Moreover, recent research finds that millions of phages dwell on us and in us—in our nose, throat, skin and gut, protecting us from bacterial infections as part of our healthy microbiome. A recent study suggested that we absorb about 30 billion phages into our bodies on a daily basis. Now, ingeniously, they are starting to be deployed as anti-microbial agents in the food industry.
A Maryland-based phage research company called Intralytix is doing just that. Founded by Alexander Sulakvelidze, a microbiologist and epidemiologist who came to the United States from Tbilisi, the capital of Georgia, Intralytix makes and sells five different FDA-approved phage cocktails that work against some of the most notorious food pathogens: ListShield for Listeria, SalmoFresh for Salmonella, ShigaShield for Shigella, another foodborne bug, and EcoShield for E.coli, including the infamous strain that caused the Jack in the Box outbreak in 1993 that killed four children and sickened 732 people across four states. Last year, the FDA granted its approval to yet another Intralytix phage for managing Campylobacter contamination, named CampyShield. "We call it safety by nature," Sulakvelidze says.
Intralytix grows phages inside massive 1500-liter fermenters, feeding them bacterial "fodder."
Photo credit: Living Radiant Photography
Phage preparations are relatively straightforward to make. In nature, phages thrive in any body of water where bacteria live too, including rivers, lakes and bays. "I can dip a bucket into the Chesapeake Bay, and it will be full of all kinds of phages," Sulakvelidze says. "Sewage is another great place to look for specific phages of interest, because it's teeming with all sorts of bacteria—and therefore the viruses that prey on them."
In lab settings, Intralytix grows phages inside massive 1500-liter fermenters, feeding them bacterial "fodder." Once phages multiply enough, they are harvested, dispensed into containers and shipped to food producers who have adopted this disinfecting practice into their preparation process. Typically, it's done by computer-controlled sprayer systems that disperse mist-like phage preparations onto the food.
Unlike chemicals like chlorine or antibiotics, which kill a wide spectrum of bacteria, phages are more specialized, each feeding on specific microbial species. A phage that targets salmonella will not prey on listeria and vice versa. So food producers may sometimes use a combo of different phage preparations. Intralytix is continuously researching and testing new phages. With a contract from the National Institutes of Health, Intralytix is expanding its automated high-throughput robot that tests which phages work best against which bacteria, speeding up the development of the new phage cocktails.
Phages have other "talents." In her recent study, Jaroni found that phages have the ability to destroy bacterial biofilms—colonies of microorganisms that tend to grow on surfaces of the food processing equipment, surrounding themselves with protective coating that even very harsh chemicals can't crack.
"Phages are very clever," Jaroni says. "They produce enzymes that target the biofilms, and once they break through, they can reach the bacteria."
Convincing the FDA that phages were safe to use on food products was no easy feat, Sulakvelidze says. In his home country of Georgia, phages have been used as antimicrobial remedies for over a century, but the FDA was leery of using viruses as food safety agents. "It took us a long time to convince the FDA phages were safe and efficient alternatives," Sulakvelidze says. "But we had worked with them to gather all the data they needed, and the FDA was very supportive in the end."
The agency had granted Intralytix its first approval in 2006, and over the past 10 years, the company's sales increased by over 15-fold. "We currently sell to about 40 companies and are in discussions with several other large food producers," Sulakvelidze says. One indicator that the industry now understands and appreciates the science of phages was that his company was ranked as Top Food Safety Provider in 2021 by Food and Beverage Technology Review, he adds. Notably, phage sprays are kosher, halal and organic-certified.
Intralytix's phage cocktails to safeguard food from bacteria are approved for consumers in addition to food producers, but currently the company sells to food producers only. Selling retail requires different packaging like easy-to-use spray bottles and different marketing that would inform people about phages' antimicrobial qualities. But ultimately, giving people the ability to remove pathogens from their food with probiotic phage sprays is the goal, Sulakvelidze says.
It's not the company's only goal. Now Intralytix is going a step further, investigating phages' probiotic and therapeutic abilities. Because phages are highly specialized in the bacteria they target, they can be used to treat infections caused by specific pathogens while leaving the beneficial species of our microbiome intact. In an ongoing clinical trial with Mount Sinai, Intralytix is now investigating a potential phage treatment against a certain type of E. coli for patients with Crohn's disease, and is about to start another clinical trial for treating bacterial dysentery.
"Now that we have proved that phages are safe and effective against foodborne bacteria," Sulakvelidze says, "we are going to demonstrate their potential in therapeutic applications."
This article was first published by Leaps.org on October 27, 2021.
Lina Zeldovich has written about science, medicine and technology for Popular Science, Smithsonian, National Geographic, Scientific American, Reader’s Digest, the New York Times and other major national and international publications. A Columbia J-School alumna, she has won several awards for her stories, including the ASJA Crisis Coverage Award for Covid reporting, and has been a contributing editor at Nautilus Magazine. In 2021, Zeldovich released her first book, The Other Dark Matter, published by the University of Chicago Press, about the science and business of turning waste into wealth and health. You can find her on http://linazeldovich.com/ and @linazeldovich.
A newly discovered brain cell may lead to better treatments for cognitive disorders
Swiss researchers have discovered a third type of brain cell that appears to be a hybrid of the two other primary types — and it could lead to new treatments for many brain disorders.
The challenge: Most of the cells in the brain are either neurons or glial cells. While neurons use electrical and chemical signals to send messages to one another across small gaps called synapses, glial cells exist to support and protect neurons.
Astrocytes are a type of glial cell found near synapses. This close proximity to the place where brain signals are sent and received has led researchers to suspect that astrocytes might play an active role in the transmission of information inside the brain — a.k.a. “neurotransmission” — but no one has been able to prove the theory.
A new brain cell: Researchers at the Wyss Center for Bio and Neuroengineering and the University of Lausanne believe they’ve definitively proven that some astrocytes do actively participate in neurotransmission, making them a sort of hybrid of neurons and glial cells.
According to the researchers, this third type of brain cell, which they call a “glutamatergic astrocyte,” could offer a way to treat Alzheimer’s, Parkinson’s, and other disorders of the nervous system.
“Its discovery opens up immense research prospects,” said study co-director Andrea Volterra.
The study: Neurotransmission starts with a neuron releasing a chemical called a neurotransmitter, so the first thing the researchers did in their study was look at whether astrocytes can release the main neurotransmitter used by neurons: glutamate.
By analyzing astrocytes taken from the brains of mice, they discovered that certain astrocytes in the brain’s hippocampus did include the “molecular machinery” needed to excrete glutamate. They found evidence of the same machinery when they looked at datasets of human glial cells.
Finally, to demonstrate that these hybrid cells are actually playing a role in brain signaling, the researchers suppressed their ability to secrete glutamate in the brains of mice. This caused the rodents to experience memory problems.
“Our next studies will explore the potential protective role of this type of cell against memory impairment in Alzheimer’s disease, as well as its role in other regions and pathologies than those explored here,” said Andrea Volterra, University of Lausanne.
But why? The researchers aren’t sure why the brain needs glutamatergic astrocytes when it already has neurons, but Volterra suspects the hybrid brain cells may help with the distribution of signals — a single astrocyte can be in contact with thousands of synapses.
“Often, we have neuronal information that needs to spread to larger ensembles, and neurons are not very good for the coordination of this,” researcher Ludovic Telley told New Scientist.
Looking ahead: More research is needed to see how the new brain cell functions in people, but the discovery that it plays a role in memory in mice suggests it might be a worthwhile target for Alzheimer’s disease treatments.
The researchers also found evidence during their study that the cell might play a role in brain circuits linked to seizures and voluntary movements, meaning it’s also a new lead in the hunt for better epilepsy and Parkinson’s treatments.
“Our next studies will explore the potential protective role of this type of cell against memory impairment in Alzheimer’s disease, as well as its role in other regions and pathologies than those explored here,” said Volterra.
Researchers claimed they built a breakthrough superconductor. Social media shot it down almost instantly.
Harsh Mathur was a graduate physics student at Yale University in late 1989 when faculty announced they had failed to replicate claims made by scientists at the University of Utah and the University of Wolverhampton in England.
Such work is routine. Replicating or attempting to replicate the contraptions, calculations and conclusions crafted by colleagues is foundational to the scientific method. But in this instance, Yale’s findings were reported globally.
“I had a ringside view, and it was crazy,” recalls Mathur, now a professor of physics at Case Western Reserve University in Ohio.
Yale’s findings drew so much attention because initial experiments by Stanley Pons of Utah and Martin Fleischmann of Wolverhampton led to a startling claim: They were able to fuse atoms at room temperature – a scientific El Dorado known as “cold fusion.”
Nuclear fusion powers the stars in the universe. However, star cores must be at least 23.4 million degrees Fahrenheit and under extraordinary pressure to achieve fusion. Pons and Fleischmann claimed they had created an almost limitless source of power achievable at any temperature.
Like fusion, superconductivity can only be achieved in mostly impractical circumstances.
But about six months after they made their startling announcement, the pair’s findings were discredited by researchers at Yale and the California Institute of Technology. It was one of the first instances of a major scientific debunking covered by mass media.
Some scholars say the media attention for cold fusion stemmed partly from a dazzling announcement made three years prior in 1986: Scientists had created the first “superconductor” – material that could transmit electrical current with little or no resistance. It drew global headlines – and whetted the public’s appetite for announcements of scientific breakthroughs that could cause economic transformations.
But like fusion, superconductivity can only be achieved in mostly impractical circumstances: It must operate either at temperatures of at least negative 100 degrees Fahrenheit, or under pressures of around 150,000 pounds per square inch. Superconductivity that functions in closer to a normal environment would cut energy costs dramatically while also opening infinite possibilities for computing, space travel and other applications.
In July, a group of South Korean scientists posted material claiming they had created an iron crystalline substance called LK-99 that could achieve superconductivity at slightly above room temperature and at ambient pressure. The group partners with the Quantum Energy Research Centre, a privately-held enterprise in Seoul, and their claims drew global headlines.
Their work was also debunked. But in the age of internet and social media, the process was compressed from half-a-year into days. And it did not require researchers at world-class universities.
One of the most compelling critiques came from Derrick VanGennep. Although he works in finance, he holds a Ph.D. in physics and held a postdoctoral position at Harvard. The South Korean researchers had posted a video of a nugget of LK-99 in what they claimed was the throes of the Meissner effect – an expulsion of the substance’s magnetic field that would cause it to levitate above a magnet. Unless Hollywood magic is involved, only superconducting material can hover in this manner.
That claim made VanGennep skeptical, particularly since LK-99’s levitation appeared unenthusiastic at best. In fact, a corner of the material still adhered to the magnet near its center. He thought the video demonstrated ferromagnetism – two magnets repulsing one another. He mixed powdered graphite with super glue, stuck iron filings to its surface and mimicked the behavior of LK-99 in his own video, which was posted alongside the researchers’ video.
VanGennep believes the boldness of the South Korean claim was what led to him and others in the scientific community questioning it so quickly.
“The swift replication attempts stemmed from the combination of the extreme claim, the fact that the synthesis for this material is very straightforward and fast, and the amount of attention that this story was getting on social media,” he says.
But practicing scientists were suspicious of the data as well. Michael Norman, director of the Argonne Quantum Institute at the Argonne National Laboratory just outside of Chicago, had doubts immediately.
Will this saga hurt or even affect the careers of the South Korean researchers? Possibly not, if the previous fusion example is any indication.
“It wasn’t a very polished paper,” Norman says of the Korean scientists’ work. That opinion was reinforced, he adds, when it turned out the paper had been posted online by one of the researchers prior to seeking publication in a peer-reviewed journal. Although Norman and Mathur say that is routine with scientific research these days, Norman notes it was posted by one of the junior researchers over the doubts of two more senior scientists on the project.
Norman also raises doubts about the data reported. Among other issues, he observes that the samples created by the South Korean researchers contained traces of copper sulfide that could inadvertently amplify findings of conductivity.
The lack of the Meissner effect also caught Mathur’s attention. “Ferromagnets tend to be unstable when they levitate,” he says, adding that the video “just made me feel unconvinced. And it made me feel like they hadn't made a very good case for themselves.”
Will this saga hurt or even affect the careers of the South Korean researchers? Possibly not, if the previous fusion example is any indication. Despite being debunked, cold fusion claimants Pons and Fleischmann didn’t disappear. They moved their research to automaker Toyota’s IMRA laboratory in France, which along with the Japanese government spent tens of millions of dollars on their work before finally pulling the plug in 1998.
Fusion has since been created in laboratories, but being unable to reproduce the density of a star’s core would require excruciatingly high temperatures to achieve – about 160 million degrees Fahrenheit. A recently released Government Accountability Office report concludes practical fusion likely remains at least decades away.
However, like Pons and Fleischman, the South Korean researchers are not going anywhere. They claim that LK-99’s Meissner effect is being obscured by the fact the substance is both ferromagnetic and diamagnetic. They have filed for a patent in their country. But for now, those claims remain chimerical.
In the meantime, the consensus as to when a room temperature superconductor will be achieved is mixed. VenGennep – who studied the issue during his graduate and postgraduate work – puts the chance of creating such a superconductor by 2050 at perhaps 50-50. Mathur believes it could happen sooner, but adds that research on the topic has been going on for nearly a century, and that it has seen many plateaus.
“There's always this possibility that there's going to be something out there that we're going to discover unexpectedly,” Norman notes. The only certainty in this age of social media is that it will be put through the rigors of replication instantly.