Some foods have a naturally bad reaction to copper and other minerals and metals. You should not store pickled foods inside copper containers, as the vinegar will react against it. Milk and drinking water are also dangerous for storing inside copper vessels, as are dairy products such as butter and cream. They will react with the metal and can cause copper poisoning. Anything citrus, like lemon juice, lime juice and orange juice, is unsafe. Yogurt also is a dubious thing to store inside copper because the acidic properties can react against the copper too. It is not advisable to eat or drink food and liquid from copper containers.
Reference : https://www.doityourself.com/stry/when-not-to-use-copper-utensils