Maryland Sea Grant Seafood Specialist Committed to Safe Seafood

July 18, 2018
This scanning electron micrograph (SEM) depicts a number of <I>Vibrio parahaemolyticus</I> bacteria; Mag. 19058x. Photo courtesy of CDC/Janice Carr

July 18th update: The Centers for Disease Control and Prevention (CDC) has now issued a warning regarding Venezuelan crabmeat. Visit their website here for more details. 

The Maryland Department of Health continues to investigate the vibrio outbreak and will provide updates as needed. The full release is available here. Vendors or restaurants with questions should call the Office of Food Protection at 410-767-8400.

The Food and Drug Administration (FDA) is issuing a similar warning. Consumers with questions should call 1-888-SAFE-FOOD. The FDA’s guidance on outbreaks is available on their website.



Vibrio parahaemolyticus fact sheet

University of Maryland Sea Grant extension agent Chengchu (Catherine) Liu, PhD, is a seafood technology specialist who has written several peer-reviewed papers on vibrio spp. and is a well-recognized expert in seafood safety. After nine people in Maryland were believed to have contracted vibrio infections from eating crabmeat imported from Venezuela, Dr. Liu put together this fact sheet. If you have any questions, please contact Dr. Liu at 301-852-8410 or


What is Vibrio parahaemolyticus?
Vibrio parahaemolyticus is a naturally-occurring bacterium found in some coastal waters and is present in higher concentrations in the summer (usually between May and October). It has been found in marine and coastal environments from the tropics to temperate regions, including the Chesapeake Bay.

What is a Vibrio parahaemolyticus infection?
Pathogenic Vibrio parahaemolyticus can cause human illness, known as vibriosis. Symptoms of vibriosis include watery diarrhea, stomach cramps, nausea, vomiting, fever, and chills.

Is vibriosis a serious disease?
Most vibriosis cases are usually fairly mild and last less than a week. People with a mild case of vibriosis recover in about three days with no lasting effects.

How do people get vibrosis?
Most people become infected by eating raw or undercooked shellfish, particularly oysters. However, other kinds of contaminated seafood can also cause the illness.

What does the Maryland Department of Health say about vibrio and the recent situation?
“The Maryland Department of Health is warning consumers to avoid eating fresh crab meat imported from Venezuela because of potential risk of infection. It is investigating a cluster of Vibrio infections in individuals who reported eating ‘fresh’ (non-pasteurized) crab meat — from a plastic tub — with a label indicating that it is imported from Venezuela.  The imported crab meat is sold under different brand names. Maryland crab product has not been associated with this cluster.”

No products have been recalled; such decisions would come from the FDA and not the state.

The state’s news release continues: “The implicated foods have been prepared in both household and restaurant settings, and include a variety of dishes, such as crab cakes, seafood salad containing crab, and crab Benedict.”

“Symptoms of Vibrio parahaemolyticus include watery diarrhea, abdominal cramping, nausea, vomiting, fever, and chills. At least nine cases who consumed imported crab meat have been confirmed in the state of Maryland. Two of the individuals were hospitalized and there have been no deaths.”

For more information, please visit the Maryland Department of Health’s website.

Vendors or restaurants with questions should call the Office of Food Protection at 410-767-8400.  

I’ve heard about people getting vibrio from the water and having serious reactions and even dying. Is this the same vibrio?
No, that infection is called Vibrio vulnificus. Unlike Vibrio parahaemolyticus, Vibrio vulnificus is much more serious and can lead to septicemia. According to the Centers for Disease Control and Prevention, about one in seven people who contract this infection die. That infection usually does not come from the consumption of seafood, but from direct contact with vibrio in the water through an open wound. It tends to affect individuals with compromised immune systems or other health challenges.

How common is vibriosis caused by Vibrio parahaemolyticus?
Vibrio parahaemolyticus infection is a leading cause of human acute gastroenteritis and is associated with the consumption of undercooked or raw seafood, particularly oysters in the United States and throughout the world.

CDC estimates that Vibrio parahaemolyticus causes 45,000 illnesses each year in the United States.

Because Vibrio bacteria are not easily identified with routine testing, many cases are not reported. But those cases that have been reported to the health department have risen in recent years. Health officials believe it is in part due to the rising temperatures.

Often, people become ill and do not connect the illness to what they’ve eaten. That makes vibrio hard to detect. Also, many doctors do not recognize the symptoms and  therefore don’t report the infections to the health department.

Who is more likely to get vibriosis?
People with compromised immune systems are more likely to get vibriosis. Those at at higher risk include:

  • People with diabetes, cancer, chronic liver and kidney disease, and AIDS.
  • Those with other illnesses that weaken the immune system
  • Those on medications meant to lower the actions of the immune system, like certain kinds of drugs for rheumatoid arthritis or cancer treatments.

I love to eat crabmeat and I prepare it at home. What do I do?
If you are buying from a supermarket, check the back of the can or tub and make sure the meat —  if it is imported — is not from Venezuela. Maryland officials encourage consumers to buy Maryland crab meat, which has not been infected. When eating crab at a restaurant, ask your server where the crab meat is from; if he or she doesn’t know, ask them to check with the chef.

What is Maryland Sea Grant’s role in protecting seafood and consumers?
Maryland Sea Grant is involved in the Maryland Crab Meat Quality Assurance (MCQA) Program. It is a voluntary quality management project jointly supported by the University of Maryland Sea Grant Extension Program, the Maryland Department of Agriculture (MDA) and of the Chesapeake Bay Seafood Industries Association (CBSIA). Each year, Maryland crab processors have the opportunity to join this program. Crabmeat processors who participate in the MCQA Program undergo evaluations, including biweekly crab meat microbiological quality tests, and assistance beyond the regular inspections performed by health regulators. 

Crabmeat is a perishable cooked ready-to-eat food that must be processed under very high quality and safety standards. The program provides extensive training and technical support to Maryland seafood businesses so that the industry is able to comply with FDA and state food safety regulations and remain current and competitive in a changing world. Routine microbiological inspections conducted through the MCQA Program ensure compliance with state regulations and the guidelines of the Chesapeake Bay Seafood Industries Association. Reports of the inspection results are sent to each participating processing plant, and may include recommendations if findings warrant changes in sanitation procedures. This information allows processors to identify procedures that most effectively control spoilage and pathogenic bacteria.

Over time, the MCQA Program has documented significant improvements in sanitation controls that meet increasingly protective requirements of regulatory agencies. Overall, bacterial numbers have declined significantly. As a result, processors are offering products of improved quality and shelf life. None of the processors Maryland Sea Grant works with in the Maryland Crab Meat Quality Assurance Program were affected by this outbreak of vibrio in crabmeat.

For more information about Maryland Sea Grant Seafood Safety and Technology Program, visit the Maryland Sea Grant website. Or watch our video “Meet the Extension Specialists: Cathy Liu, Seafood Safety and Technology.”


Photo, top left: This scanning electron micrograph (SEM) depicts a number of Vibrio parahaemolyticus bacteria; Mag. 19058x. Photo courtesy of CDC/ Janice Carr

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