Question

why should curd and sour substances not be kept in brass and copper vessels

Answer 1

As copper is metal and curd contain lactic acid that is a type of acid and we know that when acid come in contact with metal the reaction take place and make it unfit for eating

Answer 2

Curd and other sour substances should not be kept in brass and copper vessels. This is because curd and other sour substances contain acids which can react with these vessels to form poisonous compounds that can cause food poisoning and damage health.