A salmonella outbreak is being investigated by environmental health officers in North East Lincolnshire.
Most of those who fell ill had eaten takeaway food
Most of the 36 confirmed cases of food poisoning came after the victims ate takeaway food, North East Lincolnshire Council said.
Investigations are focused on one outlet, which has been given advice on the safe preparation of food.
"Our environmental health team reacted quickly and worked to limit the spread of the outbreak," the authority said.
Environmental health officers have visited the food outlet several times this week.
All the recommendations made to the owners about food preparation have now been put into place, the council said.
Councillor Martin Vickers, cabinet member for environment, added: "Officers have acted quickly to minimise this outbreak and I am confident that their prompt actions will confirm the source and solve the problem."
Symptoms of salmonella food poisoning include abdominal pains, diarrhoea and vomiting, and usually develop between 12 and 72 hours after the consumption of affected food.
Anyone who suspects they have been affected by the outbreak should contact North East Lincolnshire Council on 01472 324500.