As news has emerged of food factories around the world experiencing outbreaks of Covid-19, experts have suggested conditions inside the plants may be conducive to the spread of the virus.
Dr Simon Clarke, a cellular microbiologist at the University of Reading, told MailOnline that it was notable that food factories seemed to have been the centre of outbreaks more than other factories where people might be close together.
He said: ‘There are problems in this country, in Germany, in the United States. There is something common between them – it’s not happening in engineering or clothing factories where you also might expect people to be in close proximity to one another.
‘One assumes – but it’s just an idea – that the cold environment makes people more susceptible to the virus.
‘Cold weather irritates the airways and the cells become more susceptible to viral infection.’
Dr Chris Smith, a virologist at the University of Cambridge, said on LBC ‘temperature is going to play a part’.
He explained: ‘When I’m breathing I’m blowing out droplets of moisture from my respiratory tract and the virus which is growing in there would be packaged up in the droplets.
‘Now the droplets will hover for a period of time in the air and then sink to the ground… and if it’s very dry, cold air – and cold air carries less moisture, remember – the droplets will stay smaller and stay airborne for longer.
‘If it’s very humid, moisture joins them, makes them bigger and heavier, and they fall and they drop out of circulation faster – so temperature could be a factor.’
Sunlight is also known to degrade viruses and make them less able to survive on surfaces that are exposed to UV light.
Rays of sunlight are thought to damage the genetic material inside the virus, making it less able to reproduce and killing it faster.
Professor Calum Semple, a disease outbreak expert at the University of Liverpool, told The Telegraph that cold, sunless food factories are ideal conditions.
He said: ‘If I wanted to preserve a virus I would put it in a cold, dark environment or a cool environment that doesn’t have any ultraviolet light – essentially a fridge or a meat processing facility…
‘The perfect place to keep a virus alive for a long time is a cold place without sunlight.’
But the temperature alone does not appear to be a controlling factor in coronavirus outbreaks.
Dr Michael Head, a global health researcher at the University of Southampton, said he thought close proximity was most likely to be behind the factory outbreaks.
He said: ‘Whilst refrigeration may be a contributory factor to the spread of the virus, the key factors are likely to be the number of people close together in indoor conditions.
‘Some of these factories have onsite or nearby accommodation where there are several people in each dormitory, they may be transported on a bus to the site of work, and they will be indoors together all day.
‘Levels of adherence to measures such as washing hands is uncertain and there is unlikely to be widespread use of PPE.’