An HTML version of this document is available at                                
http://vm.cfsan.fda.gov/~lrd/sea-vib.html                                       
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FDA Fact Sheet                                                                  
February 8, 1993                                                                
                                                                                
                                                                                
                                                                                
          Advice on Consumption of Raw Molluscan Shellfish                      
                                                                                
                                                                                
                                                                                
  FDA has received inquiries about the safety of eating raw                     
molluscan shellfish such as oysters, clams and mussels.  The                    
following can be used to answer such questions:                                 
                                                                                
  Any animal protein consumed raw or partially cooked carries a                 
higher potential for causing illness than food that is thoroughly               
cooked.  Most illnesses that result in the general population from              
eating raw or partially cooked molluscan shellfish are not                      
life-threatening and commonly range from mild intestinal disorders to           
acute gastroenteritis.  Although more serious illnesses can occur,              
they are rare in otherwise healthy individuals.  The main sources               
of all of these illnesses are bacteria and viruses that are present             
in water due to human pollution.                                                
                                                                                
  On the other hand, individuals who immune systems are compromised             
should not eat raw or partially cooked molluscan shellfish at all.              
These people are susceptible to far more serious illnesses that are             
caused by naturally occurring marine bacteria from the Vibrio                   
species, particularly Vibrio vulnificus.  These bacteria are                    
unrelated to human pollution.  In susceptible people, they can                  
cause serious illness and even death.                                           
                                                                                
  Immune compromised individuals include those with liver disease,              
including cirrhosis, hemochromatosis and disease caused by chronic              
alcohol abuse; diabetes mellitus; immune disorders, including                   
advanced stages of infection with the AIDS virus, cancer and                    
reduced immunity due to steroid or immunosuppressant therapy; and               
gastrointestinal disorders, including previous gastric surgery and              
low gastric acid (for example, from antacid use or achlorhydria).               
People unsure of their medical status should consult their                      
physician before consuming raw or partially cooked shellfish.                   
                                                                                
  FDA has developed brochures for these individuals that provide                
advice about raw shellfish and related matters.  They are available             
through the FDA Seafood Hotline, at 1-800-FDA-4010 (202-205-4314,               
in the Washington, D. C., area), or from public affairs specialists             
in FDA district offices throughout the United States.                           
                                                                                
  Vibrio vulnificus and other kinds of Vibrio bacteria are often                
found in estuaries.  FDA is conducting research to discover more                
about them and how to control their presence in molluscan                       
shellfish.                                                                      
                                                                                
  Potential sources of illnesses related to human pollution are                 
better understood.  FDA cooperates with federal and state public                
health officials and the shellfish industry in the National                     
Shellfish Sanitation Program (NSSP) to maintain and improve                     
shellfish safety.  Among other activities, NSSP establishes                     
procedures for monitoring bodies of water for signs of pollution                
and closing them to shellfish harvesting when appropriate.                      
                                                                                
                                                                                
FDA Fact Sheet                                                                  
T93-8                                                                           
February 8, 1993