Apples that have been kept for a long time will smell of fermentation or wine. If the appearance is not obviously abnormal, the taste is acceptable, and it can still be eaten according to the principle of economy. \x0d\ Because fruits (especially apples) may turn into anaerobic respiration due to lack of oxygen during long-term storage, and the sugar in apples will turn into alcohol. So, we smell the wine. \x0d\ This place should be distinguished from those apples that have become soft, black and have the smell of wine. Because there are probably other harmful bacteria on this fermented apple, it is best to treat this fruit as moldy fruit. \x0d\ Different rotten fruits should be treated differently. Those rotten fruits caused by collision and freezing are still edible. As for those fruits that go bad because of mold infection, it is better to send them to the trash can as soon as possible.