Garlic turning Blue or Green

Garlic is known to contain sulfur compounds which can react with minute traces of copper to form copper sulfate, a blue and green compound. The amount of copper needed for this reaction is very small and frequently found in normal water supplies. Raw garlic contain an enzyme that if not inactivated by heating reacts with sulfur ( in the garlic ) and copper ( from water or utensils ) to form blue copper sulfate. The garlic is still safe to eat.

If fresh garlic is picked before it is fully mature and hasn't been properly dried, it can turn and iridescent blue or green color when in the presence of an acid. It may be caused by an allinin derivative.

A reaction between garlic's natural sulfur content and copper in water supply, or in the cooking utensils your are using ( such as cast iron, tin, or aliminum ) can sometimes change the color of garlic.

The other souces of copper might be butter, lemon juice, or vinegar.

Garlic will also turn green ( develop chlorophyll ) if exposed to an temperature change or is exposed to sunlight. Some people say it can be stored for 32 days at or above 70-80 degree F to prevent greening.

DON'T WORRY, GREENISH-BLUE COLOR CHANGES AREN'T HATMFUL AND YOUR GARLIC IS STILL SAFE TO EAT. ( UNLESS YOU SEE OTHER SPOILAGE )