How long foods keep and how refrigeration, containers, temperature and storage conditions affect quality and safety.
Bean or mung sprouts that have become slimy, mushy, dark, or sour-smelling should be discarded. A fresh vegetable smell is normal, but slippery tissue plus an abnormal odor points to spoilage; appearance alone cannot prove raw sprouts are free of pathogens.
A few tan or light-brown root tips can appear as sprouts lose freshness. Widespread dark brown or black roots that are soft, wet, slimy, or sour-smelling are not normal fresh-sprout quality and are a reason to discard the batch.
Slightly wrinkled or dried-out ginger is often simply dehydrated. Cut into it: if the flesh is still firm, fibrous, and normally aromatic, it is usable; mold, wet softness, slime, or an unusual odor are reasons to discard it.
Wrinkled, dry garlic can still be usable even after losing quality. Wet, mushy, moldy, deeply discolored, or off-smelling cloves should be discarded, especially when several cloves in the bulb are affected.
Dry, fibrous flesh usually points to age, maturity, or moisture loss. If the squash remains firm and clean-smelling without mold or wet decay, it can still be cooked, though the texture may be disappointing.
An onion that is watery or slimy inside has more than a freshness issue. A single dry damaged layer may be removed, but multiple soft, leaking, moldy, or foul-smelling layers are a reason to toss the bulb.
Sprouted onions are generally safe if the bulb itself is sound. The green shoot is edible too, but sprouting uses the bulb’s stored water and sugars, so texture and flavor usually decline.
A single dry brown ring can be peeled away if the rest of the onion is firm. Black powdery mold, wet or slimy layers, bad odor, or widespread internal damage means the bulb should be discarded.
A dry surface scar can often be trimmed. A wet, sunken, moldy, or leaking soft spot may extend into the flesh; if the tissue underneath is soft, water-soaked, or bad-smelling, discard the squash.
Wilted does not automatically mean spoiled. Limp but intact spinach can still be cooked if it has no slime, mold, wet decay, or off odor; slippery or mushy leaves belong in the trash.
Yellowing is mostly a freshness signal; slime is a spoilage signal. Dry, slightly yellow arugula can be used soon, while slippery, water-soaked, matted, or foul-smelling leaves should be tossed.
Lettuce that is slippery, water-soaked, and breaking apart is spoiled, not merely wilted. Remove a truly isolated bad outer leaf from an intact head, but toss cut lettuce when slime is widespread.