China links seven COVID-19 outbreaks to food packaging
China has linked seven COVID-19 outbreaks and nearly 700 cases to contaminated imported frozen food packaging materials.
The scientists said the work supports speculation that cold chain foods act as a pathway for SARS-CoV-2 and could pose a risk of transmission of the virus between countries and regions.
They added that handlers and processors of imported frozen foods should be effectively protected, monitored daily for COVID-19 symptoms and tested for SARS-CoV-2 nucleic acid at regular intervals.
Seven outbreaks and 689 cases were linked to food imported from the cold chain from June 2020 to mid-July 2021, according to the study published in China CDC Weekly.
Investigations into an outbreak at Beijing’s Xinfadi market in June 2020 revealed that five samples of salmon in the original sealed packaging in the company’s cold storage were positive for SARS-CoV-2.
An outbreak in Dalian in July 2020 was linked to food imported from the cold chain. The carrier was infected by contact with the outer packaging of frozen cod contaminated with SARS-CoV-2. Active and infectious viruses were not isolated from food samples in Beijing and Dalian.
Two infected dockworkers who transported imported frozen cod for 10 hours in two separate storage warehouses on the same freighter in Qingdao, are believed to have been infected with the virus. An active sample of SARS-CoV-2 was isolated from a sample of contaminated outer packaging of frozen cod.
The first infected cases of two outbreaks in Tianjin Municipality in November 2020 were carriers who were in close contact with contaminated outer packaging of imported frozen food, or exposed to the virus-contaminated environment while handling frozen food. frozen foods.
The viral sequence that led to the COVID-19 outbreaks of Yingkou City, Liaoning Province and Liuan City, Anhui Province in May 2021 was linked to the Dalian COVID-19 outbreak. in July 2020.
Frozen cod contaminated with SARS-CoV-2 has been kept in cold storage for 11 months in Dalian since July 2020, but still infected workers during handling. The researchers said this shows that SARS-CoV-2 can maintain its infectivity for at least 11 months at a low temperature of minus 18 degrees C (minus 0.4 F).
The study supports speculation that infected cases of COVID-19 among cold chain food handling and operating groups are likely related to occupational risk.
Another survey, published in the same journal, analyzed nearly 56 million frozen food-related samples between July 2020 and 2021.
Of the 56 million samples, 1,455 were positive for SARS-CoV-2 nucleic acid. Of 1,398 SARS-CoV-2 positive food and packaging materials, all but seven were imported.
The researchers said the findings support speculation that cold chain foods could act as carriers of SARS-CoV-2, and food handlers or operators were at high risk of exposure to the virus.
The coronavirus pandemic has impacted the global food system with direct and indirect consequences, causing widespread concern and economic hardship for consumers, businesses and communities, although it is neither a food safety problem or foodborne illness.
In Hong Kong, more than 34,000 food samples and their packaging have been tested for the virus and less than 10 have tested positive.
China launched in July 2020 a nationwide testing program for SARS-CoV-2 contamination on packaged frozen foods produced, either domestically or overseas.
Positive swabs came from seafood, poultry meat and other foods. Contamination of the outer packaging with SARS-CoV-2 nucleic acid was much more common than the inner packaging or the food itself.
The positive samples came from 11 European countries, six South American countries, nine Asian countries, two North American and two African countries.
“The survival and recovery of SARS-CoV-2 in certain foods has highlighted the importance of safe food handling practices to mitigate any public health concerns related to food contaminated with SARS-CoV-2,” said said the researchers.
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