Food-safety guidance on handling, cooking, storage, spoilage signs and when food should be discarded.
A cut onion can generally be kept about 7–10 days in the refrigerator when stored at 40°F (4°C) or below in a sealed container. That range is a storage guideline, not a guarantee: mold, slime, watery breakdown, or a clearly abnormal odor are reasons to discard it sooner.
Yes. Bread that is merely dry or hard is not automatically unsafe; staling is mainly a texture change involving moisture and starch. Bread with visible mold, unusual odors, or abnormal dampness is different, and moldy bread should be discarded rather than trimmed.
Cut avocado browns when enzymes in the flesh react with oxygen. Refrigerate it, minimize air contact with wrap pressed directly onto the surface or a small airtight container, and add a little lemon or lime juice if you do not mind the flavor.
Most U.S. extension guidance still recommends a cool, dark, ventilated place rather than a standard refrigerator because cold storage can convert starch to sugars and make potatoes taste sweeter and brown faster. A recent UK review, however, found that home refrigeration did not materially increase acrylamide-forming potential compared with a cool dark place.
Dry pasta lasts a long time because it contains little moisture. A best-by date does not make a box unsafe the next morning. Storage conditions matter more: keep it cool and dry and discard pasta exposed to moisture, mold, pantry pests, or unusual odors.
Internal black spots have several possible causes. A dry localized patch may be a bruise caused by impact or pressure; corky areas can come from growth disorders. Wet, soft, slimy, moldy, or bad-smelling tissue points toward spoilage and is a reason to discard the potato.
Black or brown strings in avocado flesh are usually vascular bundles—the fruit’s natural transport tissues—that have darkened. A few strings in otherwise normal flesh are usually a quality issue; widespread blackening, slime, mold, or a rancid smell points toward spoilage.
Yes. Sprouting is a sign of age and renewed plant growth, not toxicity. A firm, dry clove without mold or rot is still usable; the green center can taste sharper or more bitter and may be removed for flavor.
Yes. Fresh oil can be added to used frying oil that is still in good condition, but it does not restore degraded oil. Persistent foaming, rancid or off odors, unusual viscosity, or excessive early smoking are reasons to replace the oil instead.
There is no universal safe number of reuses. Oil used briefly around normal frying temperatures, filtered and stored well ages very differently from oil that was overheated, filled with crumbs or held hot for hours. Instead of counting batches, watch for persistent foam, rancid odor, heavy darkening and smoking at progressively lower temperatures.
Some potatoes become sweeter because cold storage promotes accumulation of reducing sugars, especially glucose and fructose, from the tuber's carbohydrate reserves. This is called cold-induced sweetening. Those sugars also make potatoes brown faster during frying and can increase acrylamide formation at high cooking temperatures.
Used frying oil should be discarded when its behavior has clearly changed: persistent foam, rancid or foul odor, heavy darkening, increased viscosity, or smoking at a temperature where it previously remained stable. You do not need every sign at once; obvious deterioration is enough reason to replace it.