By Julia Robins, Virginia Sea Grant Student Correspondent
A hot topic at the 2013 Virginia Aquaculture Conference this past November was how to maintain the safe consumption of raw oysters and better understand the science that directs industry harvest regulations. The forum entitled “Vibrio and You” included esteemed industry, federal and academic panelists—all there to share their Vibrio expertise: biology, regulatory framework, and future directions needed for research.
Vibrio is a bacterium not associated with pollution but naturally found in marine environments with warm temperatures. Illnesses can be incurred through consuming raw or undercooked seafood that contains the bacteria. Raw oysters appear to be most susceptible to the bacteria, and although Vibrio has only been reported in a handful of cases in Virginia, with oyster aquaculture on the rise, research is underway to keep shellfish safe to eat.
“Virginia’s shellfish industry follows strict regulations for harvest,” says Karen Hudson, VIMS extension staff affiliated with VASG. Hudson, who organized the event, noted that the central theme to the discussion was to identify gaps in scientific knowledge.
Shellfish are already regulated on a national level by the Interstate Shellfish Sanitation Conference (ISSC). Two members of the panel shared some of the new regulatory proposals that would be debated at a future ISSC meeting.
Says Hudson, “It’s important that any additional regulations are not only achievable but are represented by the best available science.”
Currently, scientists are looking for treatments and practices that could reduce risk but still offer a high-quality half-shell product at a reasonable cost.
Rapid cooling could reduce Vibrio, suggests Michael Jahncke, a food safety expert with Virginia Tech and Virginia Sea Grant Extension Partner.
“It’s not a post-harvest process, but I firmly believe this is one of the crucial things that the industry needs some training on,” he told conference attendees. Although cooling doesn’t destroy Vibrio, quick cooling makes it harder for Vibrio to grow and lowers the chance of infection.
Corinne Audemard, a Virginia Institute of Marine Science researcher, presented on another possibility currently being researched in Virginia: high-salinity relaying, transferring oysters to saltier waters before sale. Because Vibrio prefers low salinity waters, exposing the bacteria to higher salt could be an effective way to reduce it. The method has the appeal of low cost and keeping oysters alive, two advantages that other post-harvest methods lack.
Although there have only been a handful of Vibrio illnesses in the state, industry members present at the “Vibrio and You” session were enthusiastic about the need for Virginia growers to stay in front of the issue. As one attendee stated at the end of the session, “We want a solution that works.”
