It is generally recommended that pineapple soak 30 minutes of salt water can be eaten. 1. Pineapple pulp contains glycosides, pineapple protease and other substances that stimulate the oral mucosa, can cause discomfort in the oral mucosa; even pineapple protease can cause allergic reactions, the fastest can occur in the consumption of pineapple within 15 minutes of the numbness of the mouth and tongue, vomiting, flushing of the skin, the whole body itchy allergic symptoms. 2. Soak pineapple in salt water to reduce the role of allergic substances in pineapple, generally soaked for 30 minutes. A more thorough way to remove allergic substances from pineapple is to put the peeled pineapple in boiling water for 2-3 minutes, which can denature the pineapple protease and destroy the glycosides.