What Is the Green Stuff in a Lobster?

Updated April 17, 2017

The green stuff inside a lobster--also called tomalley--is a vital organ that both animals and humans eat. In fact, when raccoons prey on lobsters, they leave behind a telltale sign: the shell cracked open, with only the tomalley removed, according to the University of Maine Lobster Institute website. Many human lobster connoisseurs go straight for the tomalley, too, and consider it a delicacy. Yet, however delicious the green goo may taste, it also poses health risks.


The lobster tomalley functions as a combined liver and pancreas--also known as a hepatopancreas, according to the Bay Science Foundation website. Just like a human liver filters chemicals and contaminants from the bloodstream, the lobster tomalley serves as a "natural filter for contaminants, like dioxins, from entering the system," says the Lobster Institute website. Without the tomalley, a lobster could die from exposure to contaminants, and, according to the Lobster Institute, the meat might lose its flavour or wholesomeness.


After removing the carapace--the hard outer body shell--of a cooked lobster, look for a soft or gelatinous green substance. This is the tomalley. However, the tomalley only appears green in a cooked lobster. In a live, raw or undercooked lobster, it will appear "blackish and oily," notes the Maine Import-Export Lobster Dealers Association website.


In 2008, the U.S. Food and Drug Administration advised against eating the green stuff inside the lobster because of the risk of paralytic shellfish poisoning, according to the FDA website. PSP causes "tingling and/or numbness of the mouth, face or neck; muscle weakness; headache; and nausea," with some extreme cases causing death from respiratory failure, according to the FDA website. Symptoms typically appear within a few hours of consuming the toxin, and anyone experiencing PSP symptoms should see a doctor, cautions the FDA website.


Despite the 2008 FDA warning to avoid consumption of tomalley, the FDA states that PSP toxins do not normally accumulate in dangerous levels in lobster tomalley. The increased toxins were the result of a 2008 outbreak of red tide, an algae bloom that affected northern New England and eastern Canada, advises the FDA website. Keeping up to date with FDA advisories helps ensure safe lobster consumption.


Although eating the soft, green tomalley may pose health risks, consuming lobster meat remains safe, advises the FDA website. Because the tomalley filters toxins efficiently, contaminants do not remain in the lobster meat.

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About the Author

Karen Murdock holds a Bachelor of Arts degree in English and a Master of Fine Arts in creative writing. She has taught college composition since 2005 and written for a variety of publications since 1996.