There is intense scrutiny here in Germany on why meat production factories have been one of the most common sources of coronavirus outbreaks across the country. It's an issue that's reflected Europe-wide.
Scientists believe they may have found contributing factors that led to the country's biggest single outbreak at an abattoir in North Rhine-Westphalia - cold temperatures and an insufficient air filtration system that allowed the pathogen to spread rapidly.
More than 2,000 people have contracted Covid-19 in the Gütersloh area and the vast majority are linked to the Tönnies meat processing factory. There have been 21 deaths and 738 people have since recovered, local officials say.
Professor Martin Exner, who's leading the task force studying the causes of the plant's outbreak, told reporters that the ventilation system, designed to keep temperatures between 6C and 10C "continually recycled the same untreated air into the room".
He said it was "a newly discovered risk factor, and just one factor" adding that it "would have big consequences" for other slaughterhouses as well.
The factory is one of the biggest meat producers in the country, with an annual turnover of more than €7bn (£6.3bn; $7.8bn) last year.
According to industry analysts, more than 30,000 pigs are slaughtered each day at the site, which has a workforce of 7,000 people.
Those workers are almost entirely migrant labourers from Bulgaria, Poland and Romania. They live clustered together in workers' accommodation and now they are living under strict quarantine.
Around 2,000 staff living in the nearby village of Verl are now literally fenced off from the world, with metal gates erected in front of their high-rise flats and terraced houses.
Police and security officials keep guard. No-one can leave for at least a week.
When we arrive there, many of the workers and their families are standing together behind the barrier, in the summer heat. Several of them don't speak German or English and are confused by the situation. Others are calling out to the police to allow them to leave.
"We're European as well. We have rights. You can't put us behind a fence," one Bulgarian man shouts.
I speak through the fence to Caroline, who had been pacing back and forth trying to catch the attention of police and council workers.
"I'm so upset," she says. "I've got my family at home in Bulgaria. We normally send money over to them. They are waiting for the money to come."
Red-jacketed city council workers are on hand, trying to explain the situation over megaphones, informing the workers that they will be bringing food to them for the next few days.
Local volunteers wheeled shopping trolleys packed with food for the workers - cakes and biscuits wrapped in tin foil.
The migrant workers here tend to give the same response when I ask about conditions at the factory. They tell me they are good: "There's no problem," they say on camera.
Aid workers tell us that many migrants fear that they'll be sacked if they speak out.
Among those in quarantine are other residents in the flats who don't work at the company. One man tells me that the living conditions for some are extremely crowded. "Everyone knows about the living conditions here. Sometimes there are 16 people living in one room," he says.
Nearby, I meet Inge Bultschneider, who has been trying to help improve living conditions for the migrants which she thinks also contributed to the spread.
She says she's taken part in demonstrations in the past, because of the alleged poor state of some of them. She shows me photos of one house that appears to be full of black mould.
"This is a kitchen. You can see the mould, it smelt terrible inside. The neighbours told me there were 20 people living here. With only one bathroom."
Volker Brüggenjürgen, a worker with the Caritas charity and head of the Green party on Gütersloh council, accuses the firm of "systemic exploitation", alleging that migrant workers have been forced to work in cramped conditions for many years and given "10 minutes to eat".
He visited the plant a month ago and claims that there was no sign of any social distancing inside.
"I saw the canteen and I saw the cutting belts. Even on 15 May people were working normally," he said. "They were standing right next to each other while dismantling the meat."
Leaked video footage has emerged of workers sitting cheek by jowl in the factory canteen with no masks or social distancing evident. German public broadcaster ARD reports that the footage was taken during the pandemic.
The BBC has contacted Tönnies for a response. The company didn't want to comment on the allegations of exploitation or bad living conditions.
But earlier, they said that they "apologised" for the outbreak and "acknowledged their responsibility". They claimed the footage of workers sitting together took place "before Covid-19 started".
The wider effect of this outbreak has led to more than half a million people being placed back into confinement conditions, with the lockdown re-imposed in the regions of Gütersloh and Warendorf.
The streets in Gütersloh town centre are quiet. Police cars pass by at intervals, and families walk by with takeaway pizza boxes. It's being described by some politicians here as "lockdown light" because although shops, gyms and cinemas have closed again, some cafes can choose to remain open if "they can guarantee distancing". Aside from one sushi restaurant, most here remain closed.
Four German regions are now urging travellers from these two regions not to travel for summer holidays.
On Thursday, the Austrian government issued a travel warning for its citizens to stay away from North Rhine-Westphalia. China's Hubei province and Italy's Lombardy region are the only two other areas on the list.
Berlin-based epidemiologist Prof Timo Ulrichs tells me he believes the German government should consider further restrictions, by putting the two locked-down regions under quarantine measures.
"There is no prohibition for doing journeys, for example. This can be very dangerous as we saw in the first phase of spread," he said. "This is a similar situation. It would help for people there to stay at home and away from plans for vacations."
He also believes the pandemic has brought one advantage. "It's enabled the detection of bad conditions under which people have to work for us having our cheap meat," he said.
Overall, Germany has been held up as an example of how to tackle the Covid-19 crisis. Their stop-start approach to confinement may be a pattern that's replicated in the UK and across Europe.
The success rate of these new measures is being closely watched elsewhere.