2. Kidney beans need to be blanched before frying, because they are hard and have a special smell. After blanching, the odor can be removed and the taste is tender. It should be noted that raw or fried sword beans are easy to cause poisoning. Because it contains a toxic protein "lectin", it will cause nausea, vomiting, stomachache, dizziness and other symptoms after eating. Therefore, the beans must be fried. If it is cold, it should be cooked for at least 10 minutes.