9 Molds Trying to Take Over Your Kitchen

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iStock

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

Moldy Bread
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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
Patrick Hertzog/AFP/Getty Images

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

mold on strawberries
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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

rotten lemon put on wooden table
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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.

Does the Full Moon Really Make People Act Crazy?

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iStock.com/voraorn

Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the Moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.

This belief that the Moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the Moon are linked [PDF].

To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

When the researchers compared the time of the visits to the phases of the Moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception—in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

So rest easy (or maybe not): If people seem to act crazy during the full Moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.

This story was updated in 2019.

NASA Reveals How Living in Space for a Year Affected Scott Kelly’s Poop

NASA, Getty Images
NASA, Getty Images

When you agree to be part of a yearlong space study, you forfeit some right to privacy. In astronaut Scott Kelly’s case, the changes his body endured while spending a year at the International Space Station (ISS) were carefully analyzed by NASA, then published in a scientific journal for all to see. Kelly submitted blood samples, saliva samples, and cheek swabs. Even his poop was subjected to scrutiny.

As PBS reports, Scott Kelly’s fecal samples revealed that his gut microbiome underwent significant but reversible changes during his time in orbit. In what was surely good news for both Kelly and NASA, his gut bacteria didn’t contain anything “alarming or scary,” according to geneticist Martha Hotz Vitaterna, and it returned to normal within six months of landing on Earth.

Even after being subjected to the challenging conditions of space, “Scott’s microbiome still looked like Scott’s microbiome, just with a space twist on it,” said Vitaterna, who was one of the study’s authors.

The fecal probe was one small part of a sweeping NASA study that was just published in the journal Science, more than three years after Kelly’s return. Dubbed the Twins Study, it hinged on the results of Kelly’s tests being compared with those of his identical twin, retired astronaut Mark Kelly, who remained on Earth as the control subject.

NASA’s goal was to gain insight into the hazards that astronauts could face on proposed long-term missions to the Moon and Mars. The agency has gone to great lengths to get this information, including offering to pay people $18,500 to stay in bed for two months in order to replicate the conditions of anti-gravity.

It also explains why NASA was willing to launch unmanned rockets into space to collect samples of Kelly’s poop. On four different occasions at the ISS, Kelly used cotton swabs to pick up poo particles. When the rockets arrived to drop off lab supplies, they returned to Earth with little tubes containing the swabs, which had to be frozen until all of the samples were collected. The process was tedious, and on one occasion, one of the SpaceX rockets exploded shortly after it launched in 2015.

The study also found that his telomeres, the caps at the ends of chromosomes, had lengthened in space, likely due to regular exercise and a proper diet, according to NASA. But when Kelly returned to Earth, they began to shorten and return to their pre-spaceflight length. Shorter telomeres have a correlation with aging and age-related diseases. “Although average telomere length, global gene expression, and microbiome changes returned to near preflight levels within six months after return to Earth, increased numbers of short telomeres were observed and expression of some genes was still disrupted,” researchers wrote.

Researchers say more studies will be needed before they send the first human to Mars. Check out NASA's video below to learn more about what they discovered.

[h/t PBS]

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