A new molecular-based diagnostic test used to idenitfy the bacteria Vibrio parahaemolyticus (Vpara) in raw culture oysters will reduce the wait time for results from four days to 24 hours.
“Following the Vpara outbreak in 2015 we have been working with all affected parties to understand and improve the regulatory and operational framework for harvesting and distributing oysters for raw consumption.” said Dr. Myron Roth, the B.C. Government’s Industry Specialist for Aquaculture & Seafood. “The development of additional testing tools that are both rapid and accurate will help us achieve our goal and ensure oysters are safe to eat, especially during warm summer month when the risk to Vpara is highest.”
Vpara is a naturally occurring marine bacteria that normally poses no threat of illness from consuming raw oysters.
Numbers of the bacterium present are kept in check in by cool coastal waters, but may proliferate with increases in water temperatures and favourable biological factors.
It is critical to monitor numbers of Vpara and maintain temperature control at time of harvest, transport and distribution to stores.
During warmer summer months, monitoring is especially important to ensure Vpara does not reach levels that result in illness after consuming raw oysters.
Cooking oysters renders Vpara harmless.
Currently, the approved testing for Vpara in Canadian shellfish is via a bacterial culture test, which requires a number of days to detect bacterial through seeing colonies grown on agar plates.
By looking at DNA, scientists will be able to tell overnight if Vpara is present.
The Canadian shellfish industry has been pushing for molecular-based diagnostic testing for Vpara in order to improve shelf life for their high-value product.
Mac’s Oysters is partly funding the research along with the BC Ministry of Agriculture and the Federal Industrial Research Assistance Programme.
Dr Ahmed Siah of BC CAHS in Campbell River will lead the project team which will look for Vpara in oysters using the existing test side by side and comparing results with the new method.
“We hope the project will prove that molecular-based diagnostic testing is a practical and reliable alternative to the classical methods, and one that could eventually be accepted by Health Canada,” Siah said.
“We have confidence in the molecular technologies; we need to assure the regulatory bodies that this technique is as effective as the classic bacterial culture test for detecting Vpara.”
BC CAHS will complete the project before next summer, and pending government review and approval of the results, shellfish producers may be able to take advantage of the new test next year..
The wholesale value of B.C.’s farmed oyster industry in 2014 was $36 million.
The 2015 ban is estimated to have cost the industry over a million dollars in lost sales.
Indirectly, the ban impacted B.C.’s oyster brand, compounding lost sales and market share.
Of particular concern to producers are reduced sales of oysters not considered “fresh” while they waited results from the testing procedures.