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.

Alcohol-Producing Gut Bacteria May Harm Livers—Even if You Don't Drink

itakdalee/iStock via Getty Images
itakdalee/iStock via Getty Images

Teetotalers might think their liver is safe from the damaging effects of alcohol consumption, but new research is hinting that even non-drinkers and light drinkers might have cause for concern. It turns out a type of gut bacteria is capable of producing alcohol—and enough of it to potentially cause some pretty serious health consequences, including liver disease.

A study led by Jing Yuan at the Capital Institute of Pediatrics in Beijing, China and published in the journal Cell Metabolism offers details. After evaluating a patient with auto-brewery syndrome (ABS), a rare condition brought on by consumption and fermentation of sugary foods that leaves a person with high blood alcohol levels, researchers made an intriguing discovery. Rather than finding fermenting yeast that may have led to the condition, the patient’s stool contained Klebsiella pneumonia, a common gut bacteria capable of producing alcohol. In this subject, K. pneumonia was producing significantly more alcohol than in healthy patients.

The patient also had nonalcoholic fatty liver disease (NAFLD), characterized by fatty deposits in the liver. While many cases of NAFLD are relatively benign, too much fat can become toxic. Examining 43 other subjects with NAFLD, scientists found that that K. pneumonia was both present and potent, pumping out more alcohol than normal in 60 percent of participants with NAFLD. In the control group, a surplus was found in only 6.25 percent.

To further observe a correlation, scientists fed the bacteria to healthy, germ-free mice, who began to see an increase in fat in their livers after only one month. While not conclusive proof that the bacteria prompts NAFLD, it will likely trigger additional research in humans.

It’s not yet known how K. pneumonia acts in concert with the bacterial profile of the gut or what might make someone carrying stronger strains of the bacteria. Luckily, K. pneumonia can be treated with antibiotics. That’s good news for people who might never touch a drink and still find themselves with a damaged liver.

[h/t Live Science]

5 Hilarious Discoveries from the 2019 Ig Nobel Prize Winners

andriano_cz/iStock via Getty Images
andriano_cz/iStock via Getty Images

Each September, the Ig Nobel Prizes (a play on the word ignoble) are given out to scientists who have wowed the world with their eccentric, imaginative achievements. Though the experiments are usually scientifically sound and the results are sometimes truly illuminating, that doesn’t make them any less hilarious. From postal workers’ scrotal temperatures to cube-shaped poop, here are our top five takeaways from this year’s award-winning studies.

1. Left and right scrota often differ in temperature, whether you’re naked or not.

Roger Mieusset and Bourras Bengoudifa were awarded the anatomy prize for testing the scrotum temperatures in clothed and naked men in various positions. They found that in some postal workers, bus drivers, and other clothed civilians, the left scrotum is warmer than the right, while in some naked civilians, the opposite is true. They suggest that this discrepancy may contribute to asymmetry in the shape and size of male external genitalia.

2. 5-year-old children produce about half a liter of saliva per day.

Shigeru Watanabe and his team nabbed the chemistry prize for tracking the eating and sleeping habits of 15 boys and 15 girls to discover that, regardless of gender, they each produce about 500 milliliters of spit per day. Children have lower salivary flow rates than adults, and they also sleep longer (we produce virtually no saliva when we sleep), so it seems like they may generate much less saliva than adults. However, since children also spend more time eating than adults (when the most saliva is produced), the average daily levels are about even—at least, according to one of Watanabe’s previous studies on adult saliva.

3. Scratching an ankle itch feels even better than scratching other itches.

Ghada A. bin Saif, A.D.P. Papoiu, and their colleagues used cowhage (a plant known to make people itchy) to induce itches on the forearms, ankles, and backs of 18 participants, whom they then asked to rate both the intensity of the itch and the pleasure derived from scratching it. Subjects felt ankle and back itches more intensely than those on their forearms, and they also rated ankle and back scratches higher on the pleasure scale. While pleasure levels dropped off for back and forearm itches as they were scratched, the same wasn’t true for ankle itches—participants still rated pleasurability higher even while the itchy feeling subsided. Perhaps because there’s no peace quite like that of scratching a good itch, the scientists won the Ig Nobel peace prize for their work.

4. Elastic intestines help wombats create their famous cubed poop.

In the final 8 percent of a wombat’s intestine, feces transform from a liquid-like state into a series of small, solid cubes. Patricia Yang, David Hu, and their team inflated the intestines of two dead wombats with long balloons to discover that this formation is caused by the elastic quality of the intestinal wall, which stretches at certain angles to form cubes. For solving the mystery, Yang and Hu took home the physics award for the second time—they also won in 2015 for testing the theory that all mammals can empty their bladders in about 21 seconds.

5. Romanian money grows bacteria better than other money.

Habip Gedik and father-and-son pair Timothy and Andreas Voss earned the economics prize by growing drug-resistant bacteria on the euro, U.S. dollar, Canadian dollar, Croatian luna, Romanian leu, Moroccan dirham, and Indian rupee. The Romanian leu was the only one to yield all three types of bacteria tested—Staphylococcus aureus, Escherichia coli, and Vancomycin-resistant Enterococci. The Croatian luna produced none, and the other banknotes each produced one. The results suggest that the Romanian leu was most susceptible to bacteria growth because it was the only banknote in the experiment made from polymers rather than textile-based fibers.

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