FDA - ISSC Vibrio Vulnificus Control Plan for Oysters (09/21/95)
ISSC VIBRIO VULNIFICUS CONTROL PLAN FOR OYSTERS
ANSWERS 09/21/1995
T95-50 Brad Stone Sept. 21, 1995 (202) 205-4144
On Aug. 25, the Interstate Shellfish Sanitation Conference (ISSC) -- made up of representatives from federal and state regulatory agencies, the shellfish industry and academia -- adopted an interim control plan designed to help reduce the risk of Vibrio vulnificus infection from eating raw oysters.
The following can be used to answer questions:
Vibrio vulnificus is a potentially harmful marine bacterium that can be found in oysters and transmitted to people consuming them raw or partially cooked. Vibrio vulnificus infection is especially hazardous, even life-threatening, to individuals with serious underlying health problems such as liver disease, diabetes, cancer or immune disorders. In recent years, ISSC has considered various methods for reducing the risk of infection.
Vibrio vulnificus levels are known to increase as a function of ambient water temperature, and refrigeration significantly retards their growth. To minimize post-harvest increases in Vibrio vulnificus levels in oysters, under the interim control plan any state whose waters have been confirmed as the original source of oysters associated with two or more Vibrio vulnificus illnesses would be expected to require that the oysters be refrigerated within a specified time after harvest.
The higher the temperature of the water from which the oyster was harvested, the sooner it would have to be refrigerated. For example, oysters taken from an affected site during a month with an average monthly maximum water temperature of more than 84 degrees F would have to be chilled within 6 hours of harvesting. Oysters taken from cooler waters could be kept unchilled correspondingly longer.
FDA believes the premise that risk to consumers can be lowered through more rapid cooling of oysters after harvest is plausible. The times between harvest and cooling selected for these procedures are linked to FDA research on how rapidly Vibrio vulnificus multiplies in unrefrigerated oysters after harvest.
Since much is still unknown about Vibrio vulnificus -- for example, what levels induce illness in different individuals -- the ISSC plan also calls for establishing a committee with representatives from FDA, the Environmental Protection Agency, the National Marine Fisheries Service and other groups to develop criteria to evaluate the effectiveness of the cooling standards.
FDA views the plan as a constructive step toward addressing the Vibrio vulnificus problem, and will work with ISSC to have the interim plan in place Jan. 1, 1996. The agency will continue to work with ISSC in developing other efficient and effective means for reducing the risk of illness from Vibrio vulnificus and other foodborne pathogens.
FDA is continuing its educational campaigns on this issue. The agency continues to caution people with medical conditions that could put them at risk to avoid eating raw or partially-cooked animal protein products -- including oysters. Since some of these conditions have no symptoms, individuals may not know they are at risk. Consumers of raw oysters who are uncertain whether they are at risk should check with their physicians.
More information on oysters and related subjects is available from the FDA Seafood Hotline at (800) FDA-4010.
Hypertext updated by ear 2001-DEC-11