Hand hygiene is an area which has received a lot of attention lately, both in the health care industry and in the food industry.  As a result, there’s plenty of new research and new technologies around the topic of hand hygiene.  Here, we take a look at some old ideas and some new ideas.

Old idea:  Washing hands is all about killing bacteria.

New idea:  Removing viruses from hands – particularly noroviruses – is an equally important, if not more important, reason to strive for clean hands.

In recent years, norovirus has become the most frequently confirmed food-borne agent in outbreaks of food poisoning, in Australia and also in the USA.  The effectiveness of norovirus as a food poisoning agent is partly due to the fact that the infective dose is very low.  Human challenge studies show noroviruses to be the most infectious agents ever described.  The most common cause of norovirus contamination of food is from infected food handlers not properly washing their hands after using the toilet.  While Australian food legislation prohibits food handlers from working when suffering from a food-borne illness, norovirus can be present in workers who have no symptoms.  Even those who have recovered from the symptoms can excrete infectious particles for several weeks afterwards. Because virus concentrations in faeces can be very high, it is possible for a single food service worker with dirty hands to infect hundreds of other people.  Compared to norovirus, bacteria in low numbers on a food worker’s hands have much less potential to cause a large outbreak of food poisoning.

Old idea:  Hand-washing compliance is achieved with training, training, and more training.

New idea:  Studies in the health care industry have shown that awareness of the importance of hand washing by personnel such as doctors, does not necessarily lead to more frequent hand washing.  Observational studies of behaviour in public toilets and in food preparation environments consistently find low levels of compliance – ranging from 0% to 85% of people washing their hands when they should.  The motivation for a person to wash their hands extends far beyond work-place training.  Recent research has examined some of the psychological aspects of hand washing behaviour, with interesting results. In fact, having participants in psychological experiments wash their hands causes the subject to feel free from psychological traces of past immoral behavior, and also provides a change in their attitude to previously made decisions, reducing the need to justify those decisions.

Old idea:  Hot water washing is better.

New idea:  Recent research has found no difference in results for hot water and warm water.  For a thermal inactivation of microorganisms, the water would need to be so hot that it would burn skin.

Old idea:  Washing and drying hands effectively requires adequate time spent, proper use of soaps, and attention paid to areas between fingers, under finger nails and in wrist creases. In addition, proper facilities; a good sized sink which is conveniently placed and supplied with warm running water are mandatory.

New ideas:  Stick with the old ideas on this topic.  As more research is done on hand cleanliness, results consistently show that the most important aspect of hand washing is the mechanical removal of oil and dirt aided by the surfactant activity of the soap, and the action of the rinsing water.  New technologies such as no-touch taps and dispensers reduce the chance of post-washing contamination.  They are even thought to improve compliance, as they reduce the need to touch wet hardware after washing, allowing users to walk away with that ‘still clean’ feeling.

Old idea:  Antimicrobial soaps are a must.

New ideas: Antimicrobial soaps contain compounds that inactivate microorganisms.  In the food industry, quaternary ammonium compounds and Triclosan are commonly used.  Novel antimicrobials include silver-ion compounds and antimicrobial extracts from honey and eucalyptus.  Recent studies have found antimicrobial soaps are marginally more effective at reducing microbial loads on hands than ordinary soaps.  There’s no doubt that the use of antimicrobial soaps provides confidence in high risk food processing applications, however, they don’t increase compliance and they won’t compensate for poor hand-washing techniques.

Old idea:  Well-washed hands mean clean hands.

New idea: Hands must also be dried properly.  The drying step is just as important as washing; damp hands transfer bacteria readily to surfaces, and hands that have been dried using an unhygienic method can become re-contaminated.  In addition, slow drying methods result in poor compliance.   Until recently single-use towels were the only hygienic option, however the new generation ‘blade’ or ‘jet’ style electric dryers have proved to be an effective means of delivering dry, clean hands.

Hand hygiene has always been important to the food industry.  The emerging awareness of the risk of norovirus outbreaks means that hand hygiene is becoming more important than ever.  There are plenty of new ideas out there when it comes to hand cleanliness, although in some areas the old ideas are still the best.

By Karen Constable – HACCP  International