Specific to Pineapple, published by UC Davis Postharvest Research and Extension Center:
Soft, bright yellow flesh with gas bubbles or cavities inside“Yeast fermentation. Caused by Saccharomyces spp, is usually associated with overripe fruit. The yeast enters the fruit through wounds. Fruit flesh becomes soft and bright yellow and is ruptured by large gas cavities.” — UC Davis Postharvest Research and Extension Center
Darkened, wet-looking skin that gives way under light pressure“Thielaviopsis rot (black rot, water blister). Caused by Thielaviopsis paradoxa, may start at the stem and advance through most of the flesh with the only external symptom being slight skin darkening due to watersoaking of the skin over rotted portions of the flesh. As the flesh softens, the skin above readily breaks under slight pressure.” — UC Davis Postharvest Research and Extension Center
Brown centre or core after too long in a cold fridge“Symptoms are water-soaked, brown areas that begin as spots in the core area and enlarge to make the entire center brown in severe cases.” — UC Davis Postharvest Research and Extension Center
Wilted, discoloured crown leaves and dull colour when chilled too cold“Symptoms include dull green color when ripened (failure to ripen properly), water-soaked flesh, darkening of the core tissue, increased susceptibility to decay, and wilting and discoloration of crown leaves.” — UC Davis Postharvest Research and Extension Center
And the general signs for fruit:
Mould or fuzzy spots
Mushy, collapsed, or leaking areas
A fermented or alcohol-like smell
Slimy skin
The first list is quoted from UC Davis Postharvest Research and Extension Center, with the page each line came from linked beside it; the rest are the general signs for fruit. Never taste something to test it — when in doubt, throw it out.
Air and warmth are what shorten an opened item's life — the right container buys back the days the packaging gives up once the seal's broken.
About 5–7 days at 40°F (4°C) or below, according to USDA FoodKeeper v128. That window runs from the day you bought it — FoodKeeper publishes no separate after-opening figure for this one.
Does Pineapple need to be refrigerated?
Pineapple is shelf-stable at room temperature: cool, dry pantry, or refrigerate at 40°F (4°C) or below to keep it longer. Refrigerating it mainly preserves quality rather than safety.
How can you tell if Pineapple is bad?
Soft, bright yellow flesh with gas bubbles or cavities inside; Darkened, wet-looking skin that gives way under light pressure; Brown centre or core after too long in a cold fridge; Wilted, discoloured crown leaves and dull colour when chilled too cold. That guidance is published for Pineapple by UC Davis Postharvest Research and Extension Center. Beyond that, the general signs for fruit are: Mould or fuzzy spots; Mushy, collapsed, or leaking areas; A fermented or alcohol-like smell; Slimy skin. Never taste something to test it — when in doubt, throw it out.
Can you freeze Pineapple?
Yes — USDA FoodKeeper v128 gives about 10–12 months in the freezer at 0°F (−18°C). Frozen food stays safe indefinitely; that window is about quality, not safety.