The world's top restaurant, Noma, is in hot water after 63 diners were struck with vomiting and diarrhoea.
The incident occurred from February 12 to 16, an official report from the Danish Veterinary and Food Administration found.
It has subsequently ordered the two-star Michelin restaurant, in Denmark, to improve its hygiene standards, reported the Copenhagen Post.
Inspectors criticized Noma for not disinfecting the kitchen appropriately to prevent the contagion from spreading. It also discovered there was no hot water in the taps that staff used to wash their hands.
Health inspectors said in the report Noma also failed to react to e-mails from dinner guests who had fallen ill.
It said the restaurant, in Copenhagen, had received an official warning, AP reported.
Noma's restaurant manager Peter Kreiner apologized for the incident and said investigations were under way to track the source of the outbreak.
"Our business is based on having satisfied customers here and we're incredibly sorry on behalf of our guests," Kreiner told Danish TV2.
Noma was last year declared the best restaurant in the world for the third consecutive year in the S. Pelligrino World's 50 Best Restaurants list.
Its 20-course menu, which specializes in Nordic foods and has served dishes such as poached sea urchin and powdered cucumber, costs 2,500 kroner ($430) including wine.
Leading chef Rene Redzepi is yet to comment, and it is not known if guests have received a refund.