That black powdery coating on your onions isn't just dirt—it's most likely black mold caused by the fungus Aspergillus niger, a common post-harvest contaminant that loves warm, humid storage conditions with limited airflow.
Home cooks often assume the dark residue on the papery outer skins is harmless soil from the garden, but it's actually the powdery black spores of A. niger. This fungus thrives on onions (and other crops like grapes or peanuts) when they're stored improperly after harvest, leading to superficial discoloration along the neck and dry scales.
The good news: If the mold is limited to those outer papery layers, the onion is usually still safe. Simply peel away the affected skins (often several layers if needed), rinse the bulb under cool running water, and check that the inside remains firm, crisp, white, and odor-free—no sliminess, musty smell, or soft spots. In that case, the inner flesh is fine to use.
However, if the fungus has penetrated deeper—causing dark streaks inside, softness, sliminess, or an off odor—discard the entire onion. Cutting away visible mold doesn't guarantee safety, as some strains of A. niger can produce mycotoxins (like ochratoxin A or fumonisins), toxic compounds that may persist in the tissue even if the fungus itself is removed. Cooking kills the live mold but does not reliably destroy these heat-stable toxins, which in higher exposures have been linked to potential risks like kidney/liver strain, immune effects, or other issues (though low-level contamination from superficial onion mold is generally low-risk for healthy people).
To prevent it: Store onions in a cool, dry, well-ventilated spot (not in plastic bags), ideally in mesh or open containers to promote airflow and reduce humidity buildup.
Bottom line: A quick peel often saves the day for superficial black mold, but when in doubt (soft, smelly, or deeply affected), toss it—better safe than sorry with produce. Proper storage keeps your onions fresher and mold-free longer.
[University of California Agriculture and Natural Resources. (2023). Onion: Black Mold (Aspergillus niger). Statewide Integrated Pest Management Program]
I used to think I was rational.
Then I read Daniel Kahneman's Nobel Prize-winning work on human decision-making.
He routinely asks 8 questions to expose cognitive traps you fall into daily.
Test yourself with these questions (it's the ultimate BS detector for your brain):
⛔️🇮🇹 Migranti in Italia: abbiamo superato quota 100.000 sbarchi da inizio anno.
Erano circa 48.000 al 15 agosto di un anno fa (+101%).
In dodici mesi sono sbarcate 155.000 persone, ormai lo stesso livello del periodo 2014-2017.
Non credo che tutti si rendano conto del disastro che è salvini.
È un tizio senza arte né parte, privo di intelletto, ripetitivo, incapace di empatia, volgare, ignorante, blasfemo, sessista, ambizioso in modo deleterio.
Come fa ad essere lì dov'è?
Per tutto ciò di cui sopra.
Ho appena visto la cosa più WTF della settimana nei bagni di un fast food in piena bassa padana in cui ero entrato per lavarmi le mani e la faccia (fa caldo, non so se avete notato).
(segue)
- sfondo di #matrix.
- video di un losco #hacker in felpa con il cappuccio, di sera nella cameretta, ripreso da dietro.
Bene, ora siamo tutti più informati. Grazie tv.
Se quei 12 centesimi di accise li avesse reintrodotti un governo di csx, ora avremmo i camionisti in sciopero, i tassisti in piazza e Salvini e Meloni a guidarli sulle barricate.