At least 140 people have fallen sick in Iceland after eating food as part of a traditional feast.

On Jan. 31 and Feb. 1, Þorrablót, an Icelandic festival, was held in Grímsnes and the town of Þorlákshöfn.

The Directorate of Health and Icelandic Food and Veterinary Authority (MAST) said information was received about the illness of 67 people from Grímsnes and 73 from Þorlákshöfn, but it is possible that more fell ill.

Symptoms were primarily diarrhea and abdominal pain, but some sick people reported nausea, vomiting, and fever.

Stool samples were taken from several patients to try to identify the causative agent, and samples were also taken from food items at the festival. They came from both leftovers and foods that were still in unopened packaging from the manufacturer.

Cold chain failures

Results indicate the agent behind infections may be enteropathogenic E. coli (EPEC) and/or Bacillus cereus.

Testing revealed that jellied pork and meat from the head of sheep were contaminated with Bacillus cereus and pork was also contaminated with E. coli. Officials said high total bacterial counts indicated that food had been stored for a considerable time without adequate refrigeration, which gave the bacteria an opportunity to multiply.

Analysis of samples from sealed unopened packages revealed that products were not contaminated.

Officials said it appears the cold chain was broken and results appear to show that food was handled inadequately by the catering service.

In many reports, people mentioned that potatoes and a type of white sauce were suspected as the source, but it was not possible to take samples of those foods as there were no leftovers. Cross-contamination can occur between foods, so it is not clear wher the bacteria originated.

A type of E. coli that can cause intestinal infections was detected in stool samples collected for testing. Bacillus cereus can produce a toxin in food and the toxin causes symptoms of food poisoning if ingested. However, it is not possible to look for the toxin in stool samples, so it is not certain which one was the causative agent.

Icelandic authorities are still processing data related to the investigation, with further conclusions expected to be published in a report on the incident.

During the first inspection at the catering service, a serious non-conformity was recorded as the firm did not have an operating license. There were also inadequate handwashing facilities in the kitchen. Officials reviewed the work procedures with the caterer and will follow up to ensure improvements are made.