Question

why should the foodstuffs like orange juice, pickles, chutney and curd are not kept in iron or aluminium containers?

Answer 1

Curd contains lactic acid because it is sour in taste.  We know that metals react with acids to form salts and hydrogen gas. When curd and other sour substances are kept in metallic containers like iron vessel, iron reacts with the acid in it to form hydrogen gas and toxic substances which are unhealthy and unfit for human consumption.  It may cause food poisoning also.

Answer 2

Answer:

Curd and sour substances are acidic in nature and when they are kept in metal containers they react with them and form toxic (poisonous) elements which may get harmful for human body. That is why curd,pickles and any other sour substance is not kept in metal containers.