Alabama marine scientist receives grant to study oysters and food safety

The frequent handling exposes the oysters to elevated air temperatures and also interrupts filter feeding, and those conditions cause Vibrio levels to rise.”

—Vicki Pruente, an Auburn University doctoral student helping scientist Bill Walton study bacterial contamination in farm-raised oysters

AUBURN, Ala.—An Auburn University marine scientist has received a USDA grant to study oysters.

Bill Walton landed a $456,646 federal grant to help ensure that farmed oysters are safe to eat, the Opelika-Auburn News reported. The grant will fund a three-year study to determine whether an oyster farm’s geographic location, handling practices and choice of equipment affect bacterium levels in farm-raised oysters.

The grant is one of 13 competitive food safety awards that USDA’s National Institute for Food and Agriculture has announced as part of its Agriculture and Food Research Initiative.

“Our findings will help farmers understand and manage their preharvest production techniques to minimize the risk of foodborne illness in consumers,” said Walton, associate professor in Auburn’s School of Fisheries, Aquaculture and Aquatic Sciences and marine aquaculture specialist with the Alabama Cooperative Extension System. “These folks absolutely want to provide the safest product they can, so this is critical information for these farmers.”

The project could produce data for Gulf Coast oyster farmers, who focus on producing oysters for highend markets. Those include upscale restaurants that offer the farmed bivalve mollusks on the half shell.

One bacterium that affects oysters is called Vibrio, which occurs naturally in warm ocean waters including the Gulf of Mexico. Vibrio vulnificus can cause foodborne illnesses in people who eat raw or undercooked shellfish.

Farmers grow their oysters in underwater baskets or cages that float above the ocean floor. The baskets are raised out the water once a week to allow the oysters to air dry, which prevents barnacles, seaweed and other undesirable organisms from attaching to and marring the oysters.

“The frequent handling exposes the oysters to elevated air temperatures and also interrupts filter feeding, and those conditions cause Vibrio levels to rise,” said Vicki Pruente, an Auburn doctoral student assisting Walton on the project.

Walton and Pruente will conduct the research to establish the impact of geographic location on Vibrio levels. The research will take place at the Auburn University Shellfish Lab’s oyster research farm in Grand Bay, Alabama, and at a farm in Cedar Island, North Carolina.

“In our trials, we will look at how long after the oysters are resubmerged the Vibrio levels return to naturally occurring levels,” Walton said. “Our results will help farmers as they evaluate their production techniques.”