Coronavirus can survive on frozen meat and fish for three weeks, a new study has found.
Scientists say this could explain why outbreaks happen in countries that have not had any cases in long periods.
In the study, individual slices of salmon, chicken and pork from supermarkets in Singapore were sliced and a sample of the virus was added to them.
They were then stored in freezing temperatures – between 4C, which is standard refrigeration temperature, and minus 20C, which is standard freezing temperature.
After 21 days, researchers found the virus was still present in the fish and meat samples, The Telegraph reports.
Scientists argue transmission via contaminated food is not a major infection route, but the movement of contaminated items to a region without infections could potentially initiate an outbreak.
The study states: “An explanation is required for the re-emergence of Covid-19 outbreaks in regions with apparent local eradication.
“Recent outbreaks have emerged in Vietnam, New Zealand and parts of China where there had been no cases for some months.
“Importation of contaminated food and food packaging is a feasible source for such outbreaks and a source of clusters within existing outbreaks.
“While it can be confidently argued that transmission via contaminated food is not a major infection route, the potential for movement of contaminated items to a region with no Covid-19 and initiate an outbreak is an important hypothesis.
“An infected food handler has the potential to become an index case of a new outbreak.
“The international food market is massive and even a very unlikely event could be expected to occur from time to time.”
Prof James Wood, head of the Veterinary Medicine department at the University of Cambridge, told The Sunday Telegraph: “The authors discuss, very sensibly, how it is important that factory workers must be incentivised not to go to work when symptomatic or in contact with Covid-19 cases.”
A pig meat processing plant was shut this week after a coronavirus ‘cluster’ was discovered among 35 workers.
The meat plant, Cranswick Country Foods in Cullybackey, near Ballymena in County Antrim in Northern Ireland, mploys around 500 staff.
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Health Minister Robin Swann described the outbreak as “significant” adding that 35 staff members have tested positive, as well as a smaller number of their contacts.
A company spokesperson said: “There has been a recent increase in the number of confirmed Covid-19 cases in Ballymena and the wider region and this has been acknowledged as a community issue.
“As a result of this, we can confirm that a number of colleagues at our Ballymena site have tested positive for Covid-19.
“Working with the Public Health Authority (PHA), we have taken the decision to send all of our colleagues for testing. If the test results are positive, the individual will be required to self-isolate for 10 days; if the test results are negative, the individual will be required to self-isolate for 14 days.
“Therefore, the site will need to temporarily suspend production.”