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9 Molds Trying to Take Over Your Kitchen

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At some point in your life, you’ve likely rummaged around the kitchen for a tasty snack, opened it up, and discovered that your treat has been cheerfully consumed by a colorful fuzz. Although your reaction was probably simple—“Ick, mold!”—not all molds are made alike. There are actually a couple thousand of genera of mold within the kingdom Fungi, and many more species, each with its own special traits and talents. Specialists, generalists, molds that like it damp, or dry, or fruity—they’re living and breeding among us.

The fuzz you see is actually just the fruiting body of any given mold—namely, its spores. These hang out trying to catch a breeze on to something organic to grow on. Under the hairy bit is the body of the mold, the mycelium. If you were to cut open a moldy bagel instead of chucking it, you’d find that the mycelium’s feathery strands, called hyphae, had already feasted on the inside, excreting digestive enzymes to turn it into a smelly web.

Just what do these molds want with us and our edibles? “To reproduce and take over the world,” says Kathie Hodge, an associate professor of mycology at Cornell University. Hodge's research focuses on the classification of fungi—including molds. She also edits the Cornell Mushroom Blog.

Hodge says the ecological function of molds is to act as recyclers. But that definition “gives them short shrift," she adds. "Molds live their own vibrant and interesting lives.” Sometimes their drama plays out in your kitchen.

Here’s a tour of some of what Hodge calls the “small and elegant” entities waiting to turn your fridge into a fascinating fungus zoo:

1. RHIZOPUS STOLONIFER, A.K.A. BLACK BREAD MOLD

It’s likely that this white-then-black species is the one that took over your bagel. How? Hodge says spores may have landed on it back at the bakery, or maybe they first infiltrated some breadcrumbs that fell unnoticed behind your toaster. Rhizopus stolonifer is a bread specialist, getting to it early, eating it like crazy, and growing incredibly fast. Molds love sugar, “and as anyone on a low-carb diet knows, bread is starch, which is basically sugar and easy to break down,” says Hodge. Is it safe to eat a Rhizopus-infected bagel? “It would taste disgusting, so don’t go there."

2. PENICILLIUM CHRYSOGENUM

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It’s also possible that this puffy bluish mold is your bread-eating culprit. Yes, Penicillium is the same genus that brings you lifesaving penicillin. But don’t try to use your blue bagel as a home remedy. “I can’t tell you how many times people have said, ‘I have a cut on my arm, should I put moldy bread on it?’” sighs Hodge. Mold only morphs into antibiotics after it’s been extracted from its growth medium and purified in a lab and furthermore, the Pencillium group as a whole—there are over 300 species—is famous for making many and diverse toxins. Still, one species also makes blue cheese (Penicillium roqueforti), and another cures salami (Penicillium nalgiovense).

3. WALLEMIA SEBI

This is one of the true oddballs of the mold world—an extremophile that likes to live, as this name suggests, in extreme outposts. Extreme for a mold is a place that’s salty or super-sugary, and therefore, dehydrating. Enter Wallemia sebi, thick brownish blobs of which Hodge once found floating in her maple syrup. “It’s really slow and patient,” she says, hiding out and waiting for its time to pounce. “So, if you eat your maple syrup at a normal rate, you’re never going to see it.” Wallemia sebi is the source of some amount of controversy among Hodge’s colleagues. Some of them insist that it’s harmless. But remember, Hodge points out, “it’s been eating and excreting into your syrup. I highly recommend that people throw it out.”

4. ZYGOPHIALA JAMAICENSIS, A.K.A. FLYSPECK

flyspeck mold on green grapes
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This mold is commonly found growing on apples (and grapes), and is also known as flyspeck. Confusingly, flyspeck can be caused by a variety of mold species, varying by region and type of apple. Flyspecked apples are usually snubbed by consumers, despite the fact that their little black bumps are harmless and grow only on the skin. “It’s a hard life, being a plant,” says Hodge. “Every one I can think of has multiple fungal problems.” If you find flyspeck on your fruit at home, console yourself in the knowledge that it came in from the orchard and likely isn’t lurking in your cupboards.

5. FUSARIUM VERTICILLIODES, A.K.A. MAIZE EAR ROT

Ever peeled open an ear of corn and found a patch of pink sliming the kernels? That’s Fusarium verticilliodes, part of a huge genus that produces some truly terrible mycotoxins. It loooooves both the sweet corn you buy at the market and the field corn that’s manufactured into corn chips and fake-meat patties. And it can survive processing to cause things like estrogenic effects and immune suppression. Hence, Fusarium is highly regulated to try to keep it out of our food supply. And oh yeah, some species have also been used to make biological warfare agents.

6. BOTRYTIS CINEREA, A.K.A. NOBLE ROT FUNGUS

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Fluffy grey Botrytis cinerea will gladly sink its spores into the strawberries in your fruit bowl. It’s not particularly toxic, says Hodge, but it can gobble up fruit with lightening speed. It comes in with your berries from the field, where damp conditions make it hard to eradicate. The upside: This mold species is also known as “noble rot.” When it turns up (uninvited) on grapes in vineyards, it dries them out and concentrates their flavor; the grapes can then be used to make sweet wines like Sauternes (from France) and Tokaji Aszú (from Hungary and Slovakia).

7. ASPERGILLUS NIGER, A.K.A. BLACK MOLD

“This one is interesting,” says Hodge. “It can grow on onions—it shows up as black flecks between the layers. And it can also cause ear infections in humans.” But its talents don’t end there; Aspergillus niger also causes you to exclaim, “Ooh, lemons,” when you drink certain manufactured “lemony” beverages. (“No,” corrects Hodge. “It’s mold.”) Niger’s sister, Aspergillus oryzae, is used to make miso and soy sauce. And another, the parrot-green Aspergillus flavus, which favors peanuts and tree nuts, “is the worst fungus I can think of,” says Hodge. Its crimes against humanity include causing liver cancer.

8. DIPLODIA NATALENSIS

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Most of us have reached into the vegetable drawer and pulled out a green lemon (thanks for nothing, Penicillium digitatum). But Diplodia natalenis is responsible for an unattractive darkening—and sometimes, mush-ening—of a lemon’s stem end. This mold is also devious; it lives inside the dead wood of trees back at the grove and doesn’t actually show itself until the fruit’s already been picked, packed, and stored in your refrigerator.

9. MUCOR CIRCINELLOIDES

This little guy (gal? Other? Molds can produce spores asexually and often sexually, too) is something of a generalist. It likes fruit, vegetables, and dairy. To wit: a virulent subspecies of Mucor circinelloides was implicated in a nausea- and vomit-inducing episode that affected more than 200 people who’d eaten some moldy yogurt back in 2013. How virulent? Tests showed that it could survive passage through the digestive tract of lab mice. But how it got into the yogurt in the first place remains a mystery.

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These Sparrows Have Been Singing the Same Songs for 1500 Years
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Swamp sparrows are creatures of habit—so much so that they’ve been chirping out the same few tunes for more than 1500 years, Science magazine reports.

These findings, published in the journal Nature Communications, resulted from an analysis of the songs of 615 adult male swamp sparrows found in six different areas of the northeastern U.S. Researchers learned that young swamp sparrows pick up these songs from the adults around them and are able to mimic the notes with astounding accuracy.

Here’s what one of their songs sounds like:

“We were able to show that swamp sparrows very rarely make mistakes when they learn their songs, and they don't just learn songs at random; they pick up commoner songs rather than rarer songs,” Robert Lachlan, a biologist at London’s Queen Mary University and the study’s lead author, tells National Geographic.

Put differently, the birds don’t mimic every song their elders crank out. Instead, they memorize the ones they hear most often, and scientists say this form of “conformist bias” was previously thought to be a uniquely human behavior.

Using acoustic analysis software, researchers broke down each individual note of the sparrows’ songs—160 different syllables in total—and discovered that only 2 percent of sparrows deviated from the norm. They then used a statistical method to determine how the songs would have evolved over time. With recordings from 2009 and the 1970s, they were able to estimate that the oldest swamp sparrow songs date back 1537 years on average.

The swamp sparrow’s dedication to accuracy sets the species apart from other songbirds, according to researchers. “Among songbirds, it is clear that some species of birds learn precisely, such as swamp sparrows, while others rarely learn all parts of a demonstrator’s song precisely,” they write.

According to the Audubon Guide to North American Birds, swamp sparrows are similar to other sparrows, like the Lincoln’s sparrow, song sparrow, and chipping sparrow. They’re frequently found in marshes throughout the Northeast and Midwest, as well as much of Canada. They’re known for their piercing call notes and may respond to birders who make loud squeaking sounds in their habitat.

[h/t Science magazine]

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10 Scientific Benefits of Being a Dog Owner
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The bickering between cat people and dog people is ongoing and vicious, but in the end, we're all better off for loving a pet. But if anyone tries to poo-poo your pooch, know that there are some scientific reasons that they're man's best friend.

1. YOU GET SICK LESS OFTEN.

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If cleaning commercials are to be believed, humanity is in the midst of a war against germs—and we shouldn't stop until every single one is dead. In reality, the amount of disinfecting we do is making us sicker; since our bodies are exposed to a less diverse mix of germs, our entire microbiome is messed up. Fortunately, dogs are covered in germs! Having a dog in the house means more diverse bacteria enters the home and gets inside the occupants (one study found "dog-related biodiversity" is especially high on pillowcases). In turn, people with dogs seem to get ill less frequently and less severely than people—especially children—with cats or no pets.

2. YOU'RE MORE RESISTANT TO ALLERGIES.

Child and mother playing with a dog on a bed.
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While dog dander can be a trigger for people with allergies, growing up in a house with a dog makes children less likely to develop allergies over the course of their lives. And the benefits can start during gestation; a 2017 study published in the journal Microbiome found that a bacterial exchange happened between women who lived with pets (largely dogs) during pregnancy and their children, regardless of type of birth or whether the child was breastfed, and even if the pet was not in the home after the birth of the child. Those children tested had two bacteria, Ruminococcus and Oscillospira, that reduce the risk of common allergies, asthma, and obesity, and they were less likely to develop eczema.

3. YOU'LL HAVE BETTER HEART HEALTH.

Woman doing yoga with her dog.
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Everything about owning a dog seems to lend itself to better heart health. Just the act of petting a dog lowers heart rate and blood pressure. A 2017 Chinese study found a link between dog ownership and reduced risk of coronary artery disease, while other studies show pet owners have slightly lower cholesterol and are more likely to survive a heart attack.

4. YOU GET MORE EXERCISE.

Person running in field with a dog.
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While other pets have positive effects on your health as well, dogs have the added benefit of needing to be walked and played with numerous times a day. This means that many dog owners are getting 30 minutes of exercise a day, lowering their risk of cardiovascular disease.

5. YOU'LL BE HAPPIER.

Woman cuddling her dog.
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Dog owners are less likely to suffer from depression than non-pet owners. Even for those people who are clinically depressed, having a pet to take care of can help them out of a depressive episode. Since taking care of a dog requires a routine and forces you to stay at least a little active, dog owners are more likely to interact with others and have an increased sense of well-being while tending to their pet. The interaction with and love received from a dog can also help people stay positive. Even the mere act of looking at your pet increases the amount of oxytocin, the "feel good" chemical, in the brain.

6. YOU HAVE A MORE ACTIVE SOCIAL LIFE.

Large bulldog licking a laughing man.
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Not only does dog ownership indirectly tell others that you're trustworthy, your trusty companion can help facilitate friendships and social networks. A 2015 study published in PLOS One found that dogs can be both the catalyst for sparking new relationships and also the means for keeping social networks thriving. One study even showed that those with dogs also had closer and more supportive relationships with the people in their lives.

7. YOUR DOG MIGHT BE A CANCER DETECTOR.

Man high-fiving his dog.
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Your dog could save your life one day: It seems that our canine friends have the ability to smell cancer in the human body. Stories abound of owners whose dogs kept sniffing or licking a mole or lump on their body so they got it checked out, discovering it was cancerous. The anecdotal evidence has been backed up by scientific studies, and some dogs are now trained to detect cancer.

8. YOU'LL BE LESS STRESSED AT WORK.

Woman working on a computer while petting a dog.
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The benefits of bringing a dog to work are so increasingly obvious that more companies are catching on. Studies show that people who interact with a pet while working have lower stress levels throughout the day, while people who do not bring a pet see their stress levels increase over time. Dogs in the office also lead to people taking more breaks, to play with or walk the dog, which makes them more energized when they return to work. This, in turn, has been shown to lead to much greater productivity and job satisfaction.

9. YOU CAN FIND OUT MORE ABOUT YOUR PERSONALITY.

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The kind of dog you have says a lot about your personality. A study in England found a very clear correlation between people's personalities and what type of dogs they owned; for example, people who owned toy dogs tended to be more intelligent, while owners of utility dogs like Dalmatians and bulldogs were the most conscientious. Other studies have found that dog owners in general are more outgoing and friendly than cat owners.

10. YOUR KIDS WILL BE MORE EMPATHETIC.

A young boy having fun with his dog.
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Though one 2003 study found that there is no link between pet ownership and empathy in a group of children, a 2017 study of 1000 7-12 year olds found that pet attachment of any kind encouraged compassion and positive attitudes toward animals, which promoted better well-being for both the child and the pet. Children with dogs scored the highest for pet attachment, and the study notes that "dogs may help children to regulate their emotions because they can trigger and respond to a child's attachment related behavior." And, of course, only one pet will happily play fetch with a toddler.

A version of this story originally ran in 2015.

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