November 26, 2021
New Cold Storage Method Solves Freezer Burn—And Saves Energy
Have you ever pulled a long-anticipated pint of ice cream out of the freezer, only to find the strawberries crunchy and the normally creamy substance chalky and caked with ice? Freezer burn, a phenomenon caused by water in food crystallizing into ice inside the ice cream or fruit or meat during freezing, is a menace to taste buds, a driver of food waste, and even damages some of the nutritional benefits of food. And it’s always a risk as long as food preservation relies on very cold temperatures. Even flash-freezing, which works much faster, can still create small ice crystals.
But United States Department of Agriculture (USDA) food scientists, working with a team at the University of California-Berkeley, have a method that could help solve this problem. Normal food freezing, called isobaric, keeps food at whatever pressure the surrounding air is. But what if you change that? Isochoric freezing, the new method, adds pressure to the food while lowering temperature, so the food becomes cold enough to preserve without its moisture turning into ice. No ice means no freezer burn. And, potentially, a much lower energy footprint for the commercial food industry: up to billions fewer kilowatt-hours, according to recent research.
Ira talks to USDA food technologist Cristina Bilbao-Sainz and mechanical engineer Matthew Powell-Palm about how pressure and temperature can be manipulated to make food last longer, and hopefully taste better. Plus, the challenges of turning a good idea into a widespread technology.
Koji: The Mold You Want In Your Kitchen
When chef Jeremy Umansky grows a batch of Aspergillus oryzae, a cultured mold also known as koji, in a tray of rice, he says he’s “bewitched” by its fluffy white texture and tantalizing floral smells. When professional mechanical engineer and koji explorer Rich Shih thinks about the versatility of koji, from traditional Japanese sake to cured meats, he says, “It blows my mind.”
Koji-inoculated starches are crucial in centuries-old Asian foods like soy sauce and miso—and, now, inspiring new and creative twists from modern culinary minds. And Shih and Umansky, the two food fanatics, have written a new book describing the near-magical workings of the fungus, which, like other molds, uses enzymes to break starches, fats, and proteins down into food for itself. It just so happens that, in the process, it’s making our food tastier.
You can grow koji on grains, vegetables, and other starchy foods, and make sauces, pastes, alcohols, and vinegars. Even cure meats. Umansky and Shih say the possibilities are endless—and they have the koji pastrami and umami popcorn to prove it.
The Bacteria Behind Your Favorite Blues, Bries, and More
Cheese lovers, you can thank microbes for the flavorful funk of Camembert cheese and the perforated pattern of Swiss. According to microbiologist Rachel Dutton, one gram of cheese rind is home to 10 billion bacterial and fungal cells. Dutton describes our favorite cheese-microbe pairings and explains why the cheese rind is ripe for teaching us about the basic interactions of bacteria.
The World According To Sound: When Your Wine Bottle Sings
A few years ago, Chris Hoff was making himself some plum wine. He had a nice big plum tree in the apartment he was renting in San Francisco, and it had been a plentiful year. During the process he came across a beautiful, simple sound that made him get out his recording gear. It came from his little metal funnel.
Each time Hoff poured liquid through his funnel to fill a bottle, it made this pleasant rising arpeggio of bubbles. When the pitch reached its height, the bottle was filled, and Hoff moved on to the next one. He liked it so much that he grabbed his small handheld recorder and captured the sound.
This simple, everyday sound is the result of a complex interaction of the liquid, bottle, air, and funnel. While water pours down through the funnel, air is being forced out of the bottle and up through the liquid, where it makes a bubble on the surface and then pops. As the level of liquid decreases in the funnel, the pitch of the popping bubbles rises.
November 26, 2021
A More Delicious COVID Screener
One of the most bizarre symptoms of COVID-19—a nearly surefire way to know if you have been infected—is a loss of taste or smell. Estimates of how many people are impacted range wildly, with the highest estimates reaching 75 to 80% of COVID-19 survivors. There’s still a lot scientists don’t understand about why this happens and what part of the olfactory system or brain is actually responsible for this change.
Researchers at Ohio State University are trying to figure out more about how COVID-19 impacts taste and smell using a familiar and tasty item: hard candy. Study participants eat an uncolored piece of candy each day and describe the flavor. If a participant is suddenly unable to identify which fruit the candy is emulating … well, it’s time to take a COVID test.
Joining Ira to talk about this delicious research and learning more about how COVID-19 impacts our senses is Chris Simons, sensory scientist at Ohio State University in Columbus, Ohio.
Laugh And Learn With The Ig Nobel Prizes
This year, even though many people may be still hesitant to gather together for the holidays, a Science Friday holiday tradition lives on—our annual post-Thanksgiving broadcast of highlights from the Ig Nobel Prize ceremony, now in its 31st first annual year.
Marc Abrahams, editor of the Annals of Improbable Research and master of ceremonies for the prizes, joins Ira to present some of the highlights from this year’s awards—from research into the microbiology trapped in the gum on the sidewalk to a transportation prize for scientists who discovered the best way to safely transport a rhinoceros long distances. (Dangle it upside down under a helicopter.) Tune in to hear about research involving the kinetics of crowds, the communications of cats, thoughts about the evolutionary history of human beards, and more.
November 19, 2021
Blunting The Force Of Disease Is Complicated
COVID-19 vaccines are highly effective at preventing severe disease. But their efficacy in lab-controlled trials may not exactly correlate to how well they work in the real world.
David Kaslow, chief scientific officer at the global public health nonprofit PATH, explains that a factor known as the “force of infection” plays a role in determining how well vaccines work. The force of infection describes the attack rate of a pathogen—the amount of time it takes a susceptible individual to get infected in a given population.
In a study recently published in the academic journal NPJ Vaccines, Kaslow and his colleagues found that in vaccine trials for rotavirus and malaria in Africa, efficacy could vary widely between two trial sites. When there were many infections in the community, the overall efficacy of the vaccines appeared lower than in communities where disease incidence was low.
While the same sort of studies haven’t yet been done on the coronavirus outbreak, Kaslow argues that similar factors may be at play now—pointing to a continued need for non-pharmaceutical measures to control transmission, from masking to social distancing.
The Chemistry Of The Perfect Cookie
With several major food-related holidays on the horizon, we’ve got a challenge for you—checking your cookie chemistry. Each batch of cookies you make has the potential to be a mini-science experiment, with the specific ingredients you use, the ratios between them, and cooking times and temperatures all variables in the mix.
Jennifer Powers, a science educator at the Oregon Museum of Science and Industry, discusses the role of types of sugar in transforming your cookie’s texture from chewy to crispy. She encourages listeners to take on her educational resource—the Cookie Chemistry Challenge—to engineer the best batch of cookies possible.
Food Failures: Add A Dash Of Science To Your Thanksgiving Recipes
This Thanksgiving, put your cooking skills to the test. Looking for tips to avoid singed sweet potatoes, acrid apple pies, and a burned bird? In this archival segment from November 18, 2016, Molly Birnbaum and Dan Souza from Cook’s Science help us understand the science behind favorite Thanksgiving recipes so you can avoid food failures, and get the most out of your roast and side dishes.
America Has A Food Disparity Problem
As of 2016, more than half of American children had a diet that standard nutritional recommendations would consider “poor quality.” And there are stark differences between children in wealthier and poorer households. Poor nutrition can have lifelong impacts on health, including Type 2 diabetes, heart problems, and dental cavities. But it isn’t always clear what families need to provide healthier foods for their children. One popular explanation, now debunked, was the theory of food deserts: Poorer neighborhoods just don’t have grocery stores, and families must buy their food from convenience stores and gas stations. But if more grocery stores aren’t the solution, what is?
Sociologist Priya Fielding-Singh explores these questions in a new book, How The Other Half Eats: The Untold Story of Food and Inequality in America. Her research, the product of months of immersive time spent with families in their kitchens and as they navigated grocery stores with kids in tow, describes an alternative explanation for the socioeconomic disparity between kids’ diets. Fielding-Singh explains healthy food takes emotional and energy resources that lower-income parents must often spend in other ways.
Guest host Roxanne Khamsi talks to Fielding-Singh about her research on family food choices, and the kinds of changes that might allow children from all backgrounds to enjoy healthier foods.
November 19, 2021
Here’s How Biden’s Infrastructure Bill Addresses Science
President Joe Biden signed a massive bipartisan infrastructure bill into law this Monday. The measure focuses on a range of sectors. It would funnel billions into cleaning up pollution in the air and water with efforts that include eliminating lead service lines and cleaning up old, polluted manufacturing sites. The bill will also invest $7.5 billion to create a large-scale network of electric vehicle chargers across the country.
In other big news this week, a new study confirms that masks are highly effective in combating COVID-19, reducing incidence of the disease by as much as 53% on its own. Researchers say this finding is significant and add that when masks are used in addition to other protective measures, like vaccines and hand washing, people can feel confident in their safety.
Joining guest host Roxanne Khamsi to talk through these and other big science stories of the week is Nsikan Akpan, health and science editor for WNYC Public Radio in New York City.
Happy (Holiday) Testing Season!
The holiday season has snuck up once again, leaving many people to figure out familiar logistics: If travel will be involved, who to see, and what will be for dinner. But of course, we’re still in a pandemic, so questions of safety remain. At the end of the day, we want to keep our families, friends, and loved ones healthy.
COVID-19 tests are becoming a popular tool, helping many people make social situations safer. Quickly swabbing your nose or spitting in a tube can indicate if someone has been infected with the coronavirus. But with so many options available, and a big season of holiday get-togethers up ahead, many are wondering what kind of test is best—and when is the best time to get tested?
Joining guest host Roxanne Khamsi to talk through COVID-19 testing questions are Dr. Céline Gounder, epidemiologist and professor at New York University’s Grossman School of Medicine in New York, and Dr. Alex Greninger, assistant director at the clinical virology laboratories at the University of Washington Medical Center in Seattle.
The Big Bang Theory Of Cancer
Despite tremendous scientific advances, there’s still so much scientists don’t understand about cancer. One of the biggest remaining questions is how do tumors form in the first place?
Researchers are getting closer to an answer. For years, the prevailing theory of tumor growth was that cancer cells gradually acquire a series of mutations that enable them to outcompete healthy cells and run amok.
But improved genetic sequencing of cancers is revealing a more complicated picture. New technology has enabled a new theory of tumor development, called the big bang theory. It turns out that some types of cancer contain a whole hodge-podge of mutations right from the very beginning, even before the tumors are detectable on a scan. Researchers initially observed this pattern in colon cancer, and then replicated the findings in pancreatic, liver, and stomach cancers, too.
Guest host Roxanne Khamsi talks to Christina Curtis, associate professor of medicine and genetics at Stanford University’s School of Medicine about her research into tumor development, and how to improve cancer diagnosis and treatment.
November 12, 2021
As Wildfire Intensity Rises, So Does The Human Toll Of Blazes
It was Labor Day 2020, and Mammoth Pool Reservoir, in California’s Sierra Nevada, was buzzing with campers. Karla Carcamo and her parents, siblings, cousins, and countless others, mostly from the Los Angeles area, have been coming here every Labor Day for 17 years. “Most of it is my family, and family that’s invited family, and those family friends have invited friends of theirs,” she says. “I’m telling you, we have over 200 people.”
Alex Tettamanti and her husband Raul Reyes are also Labor Day regulars. Every year, they drive in from Las Vegas to meet up with an off-roading club made up of a few dozen families from across the West. They fill their weekend with jet-skiing, ATVing and hiking. “It’s beautiful,” says Tettamanti. “The smell of all the pine trees and stuff, and the trees are so big, it’s really cool.
The campground and reservoir are nestled at an elevation of about 3,000 feet in the Central California foothills a few hours northeast of Fresno. The attraction is unfiltered Sierra Nevada: Sparkling blue water surrounded by a thick forest of stately ponderosa pines and black oaks. Plus, it’s isolated. There’s only one road in and out, which dead ends at the lake. “Being there, let me tell you, it’s like a little piece of paradise,” says Carcamo.
That Friday passed like any other. Groups split up to go hiking, swimming and grilling, and Carcamo’s family prepared for their annual pupusa night later in the weekend.
By Saturday morning, however, the atmosphere had changed. “When I woke up, I did notice it was kind of cloudy,” says Reyes. “The sky was orange and there was ash, like big pieces of ash falling,” says Reyes’ friend Vicky Castro.
Squirrel-Nut Economics And Other Agility Tricks
In many parts of the country, the lead-up to winter is a busy time for squirrels, furiously collecting and hiding acorns and nuts for the cold months ahead. But how can squirrels recall where it has stashed all its stores? And what can studying squirrels tell researchers about memory, learning, and economic decision-making in other species?
Ira talks with Lucia Jacobs, a professor in the department of psychology and the Institute of Neuroscience at UC Berkeley, about her studies of the campus squirrels—from learning about their cognition, learning, and memory to recording the acrobatic movements of a squirrel on the ground and in the treetops. Jacobs co-leads a "squirrel school," observing rescued and orphaned juvenile squirrels as they learn normal squirrel behavior, and is contributing to a project seeking to develop robots using agility tricks learned from the rodents.
What Will We Reap Without Topsoil?
You may have missed the research when it came out this February: a paper in the Proceedings of the National Academies of Science reporting on satellite studies of farmland topsoil in the nation’s corn belt, states like Iowa, Indiana, and Illinois. And the news was not good. The team estimated that more than one-third of the topsoil in this region is gone, eroded mostly from hilltops and ridgelines, thanks to the plowing and tilling processes used to perform industrial agriculture. That topsoil, some of the richest in the world, is carbon-rich and crucial to our food supply. And yet it’s continuing to wash away, a hundred years after scientists like Aldo Leopold first called out the threat of erosion.
This erosion, as well as other degradation of soil’s complex structure and microbiome, continues at a fast clip around the globe, hurting food production and ecosystems health. In addition, soil could be helping us contain more than 100 billion additional tons of carbon dioxide from the atmosphere—if we let it. But the good news, according to University of Wisconsin soil scientist Jo Handelsman, is that the solutions like cover crops and no-till farming are simple, well-understood, and easy to implement—as long as we give farmers incentives to make the leap. She talks to Ira about her forthcoming book, A World Without Soil: The Past, Present, and Precarious Future of the Earth Beneath Our Feet.