Food - Drink
How Is Mercury Tested In Tuna?
It is a known fact that of all fish, tuna has the greatest mercury content. There are several methods for testing tuna for mercury, and because testing has historically been inconsistent, there is no assurance that tuna purchased in larger amounts is safe.
Tuna testing is done under specific requirements, such as those for pouched tuna from the United States Department of Agriculture (USDA), where three distinct 3-ounce samples of tuna are tested. The mercury level cannot be over 1 part per million, and the test is run a minimum of 12 times.
Although it is not specified how the test is carried out, it is most likely done by breaking food apart and examining what remains. Since there is no reliable method for measuring the mercury content in tuna at home, it is better to limit weekly tuna consumption well below the recommended quantity.