Calling all Moscow Mule lovers: Those copper mugs could be poisonous

If your favorite alcoholic beverage is the Moscow Mule, you may want to order with caution. Those copper mugs could be poisonous, and Iowa is now prohibiting the use of them.

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The state made the announcement this week in a news bulletin, revealing that it will be adhering to the FDA code that "prohibits copper from coming into direct contact with foods that have a pH below 6.0." Other liquids that meet this criteria include wine, vinegar and fruit juice.

The statement said the pH of a traditional Moscow Mule “is well below 6.0.” Therefore, copper mugs with a copper interior can no longer be used, but copper mugs lined with other metals such as nickel or stainless steel can be.

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Iowa is implementing the new law to address inquiries regarding the safe use of copper mugs.

Studies have found that high concentrations of copper can be poisonous and lead to symptoms such as stomach pains, vomiting and fatigue.