Norovirus research reveals knowledge gaps

By Joseph James Whitworth

- Last updated on GMT

Picture: ©iStock
Picture: ©iStock

Related tags Food standards agency Hygiene

Inadequate hand washing, using bare hands when preparing food and returning to work too early after being ill were some findings of work to prevent the spread of norovirus.

Participants often reported recognition or awareness of the term norovirus but knowledge was typically very low.

There was often either a lack of knowledge or confusion about what norovirus is and how it is contracted and transmitted.

What was more surprising was the gap in awareness, and application of, recommended behaviours for generic hygiene practice such as what constitutes effective hand-washing and drying.

There was little understanding of the potential consequences and no beliefs about the negative consequences of not engaging in hygiene behaviours related to norovirus.

Stop norovirus spread

The purpose of the Food Standards Agency study​ was to help stop norovirus from spreading, by understanding and improving food handler behaviours.


Clinical characteristics of norovirus include frequent projectile vomiting, diarrhoea, abdominal cramps, headaches and nausea. Symptoms, which encompass an incubation period between 10 and 50 hours following exposure, can last between 12 and 48 hours (ACMSF 2015). Characterised by low infectious dose, ~10 virus particles (ACMSF 2015), alongside high level of viral shedding that can persist for more than three weeks it is considered a highly contiguous pathogen.

There was a suggestion that other potential sources of illness such as E. coli and Salmonella had greater recognition.

In 2014, the Food Standards Agency (FSA) estimated 74,000 cases of foodborne norovirus infection in the UK

Norovirus has frequently been linked to raw or lightly cooked shellfish, principally from oysters, as well as fresh produce, particularly soft fruit. However, introduction by infected food handlers is thought to be a significant contributor to human infection.

In November 2015, FSA funded a study by Ipsos MORI to enhance understanding of norovirus transmission in the catering sector.

A literature review identified personal hygiene, food handling, washing and cooking food, surface and uniform cleaning and fitness to work as control strategies. These strategies consisted of a number of ‘key practices and behaviours’.

Visits to 32 catering establishments involved interviews, surveys and environmental and behavioural observations.

Almost a quarter (8/37) of respondents said when it is busy it is hard to carry out hand hygiene and 6/37 reported that kitchen layout, equipment and procedures make hand hygiene difficult.

EFSA recommends the most effective method for reducing norovirus contamination on hands, is washing them for 20 seconds with soap and running water and drying for a further 20 seconds with disposable paper towels.

There was ‘very little’ evidence this recommended practice took place in establishments included in the research.

“The regularity and frequency of handwashing was highly variable. Even in instances where food handlers regularly washed their hands they tended to do so inadequately.

“Typical features of inadequate handwashing were not washing hands prior to food preparation, not washing hands for long enough, not drying hands for long enough, as well as inconsistent use of soap and disposable paper towels.”

There was evidence of support for non-recommended practices from senior staff such as supporting the use of alcohol gels as an alternative to soap and water.

Behaviour in UK kitchens

Meanwhile, more than 30% of 200 chefs had worked in a kitchen within 48 hours of suffering from diarrhoea and/or vomiting, according to a study​.

UK based researchers from The University of Manchester, Bangor University and the University of Liverpool found 16% had served barbeque chicken when not sure it was fully cooked.

The ENIGMA Project also revealed 7% did not always wash their hands immediately after handling raw meat or fish.

Professor Dan Rigby, of The University of Manchester and one of the lead authors, said foodborne illnesses impose a huge burden to the UK population.

“It is notable that chefs in fine dining establishments were more likely to have returned to work too soon after suffering diarrhoea and/or vomiting, contravening UK regulations - this may be that fear of losing a prestigious job, or a desire not to let the team down, is causing people to not to stay away for long enough, putting the public at risk.

“Staff currently working in kitchens with higher prices, more awards or a good Food Hygiene Rating Scheme were no less likely to have committed  the bad behaviours , or have worked with colleagues who had in the past  - meaning that the public face a difficult challenge to protect themselves from these bad kitchen behaviours.”

Researchers used the Randomised Response Technique (RRT) which involved those surveyed rolling two dice in secret and switching answers (Yes to No; No to Yes) according to the values they rolled.

Dr Paul Cross from Bangor University's School of Environment, Natural Resources & Geography said: “Whilst this may appear to be an unexpected use of dice, it has been repeatedly demonstrated that it is the most effective method for obtaining honest answers to very sensitive questions.”

Related topics Food safety & quality

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