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Oyster researchers help protect consumers from dangerous pathogens

Vibrio parahaemolyticus is the leading cause of seafood-borne bacterial infections in the United States. Contaminated raw oysters can cause vibriosis, a gastrointestinal disease that can be fatal and even fatal for people with liver disease, diabetes, or weakened immune systems.

vibrio the diseases are notorious for showing the largest increase — 116% — in infection rates from those seen in the mid-1990s, according to the Centers for Disease Control and Prevention.

Unfortunately, there are myths that encourage people to eat raw oysters despite these dangers. Myth: Eating raw oysters is safe if you drown them in hot sauce, which kills everything. Fact: False. Myth: Alcohol kills harmful bacteria. Fact: False. Myth: Avoid raw oysters during months without the letter “R” and you will be safe. Reality: You’re kidding, aren’t you?

Fortunately, researchers at Land-grant universities have discovered how to detect and treat vibrio-contaminated oysters with support from the USDA’s National Institute of Food and Agriculture (NIFA), protecting both consumers and the market for farmed oysters.

Detection of vibrios

Researchers at the New Hampshire Agricultural Experiment Station in University of New Hampshire have developed an inexpensive and reliable method for vibrio detection. The method quantifies the levels of dangerous pathogens and harmless non-pathogens. vibrio strains. The test more accurately assesses pathogens vibrio levels of risk throughout the life cycle of seafood consumption.

The test is essential for New Hampshire’s growing oyster industry, which dominates the state’s aquaculture industry. The number of oyster farms in Granite State grew faster than any other state – a 229% increase – from 2013 to 2018, according to the USDA US Aquaculture Census. Unfortunately, when outbreaks occur, the response is usually to shut down oyster farms. Even temporary closures can stifle the industry and result in significant losses for oyster farmers.

Fortunately, the patented test more accurately assesses vibrio-related risks and can be used throughout the life cycle of seafood products, including harvesting, processing, distribution and consumption. This distinction can benefit multiple markets by providing a more accurate risk assessment for food inspectors, producers, wholesalers and retailers; or provide more accurate public health information to researchers, government, and regulators. The diagnostic test can be used in a traditional laboratory environment and adapted as a field test kit.

Reduce vibrios

Aquaculture production of off-bottom oysters is increasing dramatically in the United States as raw oysters gain popularity in the premium half-shell market. However, there are risks associated with this form of oyster farming as the oysters require frequent handling to improve oyster quality. This manipulation exposes the oysters to high air temperatures and interrupts the feeding of the filter, resulting in populations of Vibrio vulnificus and Vibrio parahaemolyticus.

To protect the market for farmed oysters, it is essential to minimize the potential risks of vibrio infection during the growth process, before harvesting the oysters.

To minimize the risk of foodborne illness among consumers, researchers at the Alabama Agricultural Experiment Station at Auburn University Shelfish Research Lab investigated how handling practices, gear type and geographic region can affect levels of vibrio in cultured oysters, as well as the determination of the re-submersion period necessary to bring the high levels of vibrio back to normal in the oysters.

The results showed that all vibrio recovered to ambient levels after seven to 14 days of re-submersion, regardless of handling type, gear type or region. This means that after a routine handling treatment, farmers must leave the oysters in the water for 14 days before harvesting them for human consumption. Thanks to this study, oyster farmers now understand how to manage their pre-harvest production techniques to minimize the risk of food poisoning to consumers, thereby protecting oyster farmers’ profitability.

Top photo: Left image of hands holding oysters. Right image of an oyster farmer examining oysters. Images courtesy of Adobe Stock.

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