In the summer we use to keep the fruits in the fridge so that the fruits outside will get used to or get old due to the high heat but a few vegetables should not be used as such.
This is because the nature of a few foods and food items vegetables and fruits will change
So you can see why mangoes and watermelons should not be kept in the fridge. It changes its taste and color and is prone to bacterial growth. Similarly, storing mangoes and mangoes in the refrigerator may change their taste as well as the top of the mango may turn black and the color of its mango may change.