The BBC and Wales Online have reported the story.
Forty people were taken ill after a sickness outbreak beginning on Mother's Day Public Health Wales linked to Old Railway Line Garden Centre in Powys.
Health officials are investigating what caused the outbreak, which is said to be short-lived.
The centre's owner said it was likely the norovirus sickness bug had spread.
Owner Mark Cleary told the BBC: "Customers we have been in contact with have symptoms closely matching those of the nasty norovirus which is currently widespread throughout south Wales.
"It is likely that one or two of the hundreds of visitors we welcomed that day has brought the virus or something similar with them and passed it on to others.
"It is also worth noting that some of the people with the illness did not visit or eat in our restaurant last Sunday."
Sion Lingard, consultant in health protection for Public Health Wales told Wales Online: "We are aware of 40 people who have become unwell after visiting the Old Railway Line Garden Centre and officers of Powys County Council are continuing to speak to those affected to determine the source of their infection.
"At this time all those who have reported being unwell were at the premises on Sunday 6 March."
The premises remains open for business as usual.