Salt trade was a very efficient trade. Many people learned about salt this way. North-Africans transported salt around the continent using camels. This was called the Trans-Sahara Trade. This is one of the many ways of trading.
Soon enough, people learned that transporting salt was not as profitable as selling or trading salted goods. Salted cod was very popular at the time because it would not spoil for a very long time. People in Europe made a lot of money through the trade of salted cod. Other items that were traded were eel, herring, and other foods.
Some people decided to trade salted cheese and vegetables. These salted vegetables are now called pickles. Cheese was very salty at the time because they were rubbed with salt.