Caterer linked to norovirus outbreak in Australia

More than 60 people fell sick in a food handler-related norovirus outbreak in Australia.

The outbreak affected six events where attendees consumed food provided by a single catering business in the Australian Capital Territory (ACT). The infection source was suspected to be a food handler with no symptoms and inadequate food handling controls allowing contamination of certain products.

In November 2022, the Australian Capital Territory Health Directorate (ACT Health) received complaints of gastrointestinal illness from two events with food provided by the same business.

Event attendees were emailed an online questionnaire. A separate questionnaire was sent to catering business employees who worked between Nov. 14 and 18.

Spreading norovirus while feeling fine
In total, 129 of 157 event attendees completed the survey and 64 reported gastrointestinal illness. According to a study published in Communicable Diseases Intelligence, cost estimates of non-fatal productivity losses for a norovirus outbreak of this size were AUD $23,700 (U.S. $15,100).

The median age of cases was 47 with a range of 15 to 69 years old and 41 patients were female. The median incubation period was 33 hours and the median duration of illness was 68.2 hours.

The most commonly reported symptom was nausea, followed by vomiting, diarrhea, and abdominal pain. Six cases sought medical attention, including four who went to the emergency department. There were no hospital admissions or deaths.

Analysis of data collected on Nov. 16 identified that illness was significantly associated with consumption of vegetarian rice paper rolls. The next day, any sushi, but particularly teriyaki beef sushi and tuna sushi, as well as roast beef wraps were associated with illness.

Testing for norovirus in food and environmental samples was not conducted. Seven fecal specimens were positive for norovirus. While no food handlers reported illness prior to the outbreak, one food handler said their child had had gastroenteritis in the preceding week.

Fourteen employees were working at the catering premises during the implicated week. Five were involved in food preparation and handling. One food handler had a pre-school child who had vomiting and diarrhea in the week before the outbreak. This person was involved in the preparation of sushi, vegetarian rice paper rolls and sausage rolls on one day; and wraps, sushi, vegetarian rice paper rolls and sausage rolls on the next. They reported no symptoms of gastrointestinal illness.

Past outbreak and inspection findings
Three employees from the business, one food handler and two drivers, developed gastrointestinal illness during a week in November 2022. None reported sick contacts and all three had consumed food made on the premises.

The proprietor had received a complaint from a customer and was anticipating the inspection. The business had been implicated in a foodborne norovirus outbreak in 2019. However, the catering firm owner did not understand that the previous outbreak was also attributed to the caterer.

“It is important that businesses implicated in foodborne disease outbreaks are informed of and understand the findings of outbreak investigations in order to modify and maintain food safety practices,” said researchers.

Inspectors found there was no designated food preparation sink. However, the walk in freezer floor was not clean and needed replacing to allow effective cleaning; and there was potential for cross contamination of food items in the freezer due to lack of organization. Other issues included sinks in the staff toilets too small to allow effective handwashing, no documented employee exclusion policy, and inadequately maintained staff illness records.

Microbiological testing of seven food samples produced two marginal results: coagulase positive Staphylococcus in a sandwich egg mix and a high standard plate count in the roast beef.

“The source of the contamination was most likely an infected food handler at the catering business and not a specific ingredient as no outbreaks were detected outside of event attendees and their contacts, and there were foods with unrelated ingredients associated with illness,” said researchers.

“This study demonstrates the importance of effective hand hygiene and food handling practices at all times, given that asymptomatic individuals can excrete and transmit norovirus and these outbreaks can be large and costly.”

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Source: https://www.foodsafetynews.com/2025/05/caterer-linked-to-norovirus-outbreak-in-australia/