Health chiefs have been investigating how two food factory workers contracted Legionnaires' disease.
Thousands of people visit the factory's visitor centre every year
The two people, who work at Baxters of Speyside in Fochabers, Moray, were treated in Aberdeen. A third possible victim is undergoing tests.
The plant, which makes soups and preserves, has been closed until the weekend as a precaution. The firm stressed there was no risk to products.
The disease is a potentially fatal form of pneumonia.
It is not passed from person to person but is spread through contaminated water systems such as air conditioning units.
Chest and abdominal pains
A spokesman for NHS Grampian said: "Baxters of Speyside is included in this investigation and has been co-operating fully.
"NHS Grampian has informed all GPs and out of hours medical services."
It is known that a middle aged man has been affected, but there were no details about the other patient. Their conditions were not known.
Baxters cancelled its night shift on Wednesday.
On Thursday, a Baxters spokeswoman said: "There will be no production at the factory today and the visitors centre will also be closed.
"Workers are being sent home and the situation will be reviewed on a day to day basis.
"We can confirm that there is absolutely no risk to any products manufactured in our factories at Fochabers."
Facilities will remain closed on Friday.
The firm said it was regularly in touch with all the families concerned.
Managing Director Norman Soutar added: "Our first thoughts at this time remain with our employees and their families.
"This is a difficult time for them and we have offered whatever support they require."
The disease got its name following an outbreak among members of an ex-servicemen's organisation, the American Legion, at a conference in Philadelphia in 1976.
It causes a flu-like illness, with muscle aches, tiredness and fever.
People become infected when they breathe in air that contains legionella bacteria.
Outbreaks tend to occur in people who spend time in buildings such as hotels and factories where the cooling systems or showers have been contaminated by the disease.
NHS Grampian has set up a helpline for anyone concerned about the discovery of legionella at the factory on 08000 28 28 16.