CDC: Frozen raspberries were culprit behind 2019 norovirus outbreak on multiple cruises
Passengers contemplating boarding another cruise after the coronavirus pandemic might already be planning to pass up the buffet next time they sail due to social-distancing concerns – assuming ships don’t do away with them anyway. But a new report published Friday by the Centers of Disease Control and Prevention spotlights the smoothie bar, too.
The study identified frozen fruit – namely raspberries – used to make smoothies as the culprit of a norovirus outbreak that infected hundreds of passengers on multiple cruises from a single company in 2019.
Between July and September 2019, the unnamed cruise line experienced “sudden, unexplained outbreaks” of acute gastroenteritis passed between passengers sailing on 10 ships in Europe, according to the CDC. While the outbreak went on throughout the summer, the cruise line’s investigations “yielded no clear source” of the outbreaks though food was tested extensively.
The CDC study found the symptoms – the rapid onset of vomiting and diarrhea followed by recovery within a 24-hour period – to be consistent with norovirus. The highly contagious virus can be transmitted through contaminated food or water, direct contact with an infected person or touching contaminated surfaces.
The CDC’s Vessel Sanitation Program (VSP), which works with the cruise industry to prevent and control the introduction, transmission and spread of gastrointestinal illnesses on passenger ships, was first notified about the situation in September. Any ship with 13 or more passengers or that has a foreign itinerary with U.S. ports is under its jurisdiction.
On Sept. 18, the VSP was notified of an acute gastroenteritis outbreak on one of the cruise line’s ships that was sailing into New York from Germany.
Five stool samples from the second and third voyages investigated were taken by the CDC and overall, nine of the 11 samples taken from the three voyages tested positive for norovirus.
After reviewing food questionnaires from passengers on the round-trip New York City voyage, the CDC found that 80% of those sickened “implicated a smoothie made from frozen fruits and berries.”
Berries have been the source of norovirus outbreaks in the past, according to the CDC, which brought in the Food and Drug Administration in to collect frozen fruit and berry samples from the ship for testing.
The FDA tested 16 fruit groups from the ships and found that three items tested positive for norovirus: Tropical fruit cocktail, raspberries and berry mix.
Later, the cruise line learned its food vendor had bought nearly 22,000 pounds of frozen raspberries at the end of June – right before the outbreak began – from a supplier in China. Those berries were provided to the cruise line’s entire fleet.
In November, the discovery prompted the World Health Organization to issue a recall on frozen raspberries traced back to China.
CDC spokesperson Jennifer Burchfield would not confirm the cruise line in question. However, she said, “Ten of the 13 outbreaks occurred while the ships were not sailing in U.S. jurisdiction. We do not know the total number of people infected during this multi-ship outbreak.”
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