If kept in the refrigerator, freshly cut pineapple will last for a lot longer than you think. I’ve had pineapple the fridge for over a week without any issues. If you’re concerned about it going bad, use the smell or taste test. Soured pineapple will also have an “off” taste, almost like sour meets fermentation, and the sweetness will be gone. Trust me – you’ll know it when you taste it.