Seafood That Glows in the Dark

The bacteria Photobacterium phosphoreum is probably the most common cause of glowing seafood. Other marine bacteria including Alteromonas hanedai, P. leiognathi, Vibrio fischeri, V. harveyi, V. logei, and V. splendidus also cause glowing or luminescence when they grow on seafood products.

Luminous marine bacteria are common in the marine environment, and on the outer surfaces and in the intestines of marine animals. Some species of Photobacterium are also in specialized luminous organs of marine fish.

Most luminous marine bacteria grow at temperatures as low as 39°F. P. phosphoreum and V. logei can grow at 32°F. These bacteria are able to grow on seafood in there frigerator, but they require sodium or salt to multiply.

Luminous marine bacteria may not grow well on some seafood products because the seafoods do not contain enough salt. Seafoods such as cooked crabmeat, cooked shrimp, and simulated seafood products made from surimi have salt added during processing. These products are the most common seafoods associated with luminescence or glowing.

When seafood glows it means that many luminous bacteria are present. This suggests that the seafood was held for a time and at a temperature where these bacteria could grow. It does not mean the seafood is unsafe or low quality. There are no reports of illness from luminous marine bacteria growing on seafood.

Refrigerate all seafood products as close to 32°F as possible to slow the growth of bacteria. Consume cooked seafood products within a day or two after purchase.

The author is Robert J. Price, Ph.D., Extension Seafood Technology Specialist, Department of Food Science & Technology, University of California, Davis, California 95616-8598.

UCSGEP 90-8 August 1990