Hand Hygiene

by Prof Chris Griffith

The previous two articles examined first of all cross contamination and then the importance of surface cleanliness and cleaning within cross contamination. The third critical element in this topic is the link with hand hygiene.

Studies have shown that the hand flora, microorganisms carried on hands, varies considerably although a general division is often made into resident and transient organisms. Resident organisms, including Staphylococcus aureus attach easily to, and survive well  on, the skin’s surface which they can readily colonise. Their presence is relatively independent of the type of soil in contact with the hands . Transient organisms, which includes coliforms and others of intestinal origin, attach weakly to, survive poorly on hands, are easily washed off and their presence is linked to the type of soil in contact with the hands.

Research shows that hands, especially in retail and food service, are one of the surfaces most likely to be the last thing to touch ready to eat food prior to consumption. Furthermore (linking back to cleanliness and cleaning) the surfaces hands touch prior to contact with ready to eat foods are often contaminated and that compliance with hand hygiene requirements is often poor. Transfer rates of microorganisms  from the hands to food can be high, illustrating the rationale behind the CDC in the USA stating that hand hygiene is the single most important food safety control practice and that improved hand hygiene could prevent over 20 million cases of food poisoning  a year in the USA alone. To many people the obvious perceived solution is to educate /train people in hand hygiene. However this misses the main problem which is not that food handlers do not know  or even understand hand hygiene is important but that the problem lies with them “doing “ it ie its non implementation. Whilst hand washing is important good hand hygiene is much broader than this and must be based on the fact that 100% compliance is highly unlikely.

People working in the food industry must themselves be in good  general health (eg no stomach upsets) as well as having good hand health. Freedom from infected cuts, lesions, spots etc helps to ensure that hands will not harbour, have resident pathogens, in the first place. Having good hand habits eg not smoking, touching  the nose, spots, or other contaminated surfaces means both fewer resident and transient organisms. Work practices can be devised, eg use of tongs in serving food or thin polythene bags/greaseproof paper in slicing or dispensing food to reduce hand contamination of foods. Bare hand contact with foods can also be prevented by the use of gloves ( a legal requirement in some states in the USA). Gloves do have a role to play in good food hygiene although there is insufficient space to go fully into their use/abuse  and possible disadvantages. Suffice to say wearing gloves, which should be changed frequently  should NOT be used as an excuse for a reduction in hand decontamination as, used incorrectly, they can be as much, if not more, of a problem than contaminated hands.

Hand decontamination is a term now frequently used to encompass the activities of both hand washing and hand disinfection. The latter often being achieved by alcohol based gels or foams or other antimicrobial  agents. It is important to realise that this is a fundamentally different process. Hand washing is cleaning, which in the process also removes some of the microorganisms, and  includes the related but  often forgotten act of hand drying. The use of antimicrobial agents is disinfection ie purely a reduction in the number of  some microorganisms  and as such can only be used on hands free of visible food soil. Each of these two activities have their respective advantages and disadvantages and used correctly can contribute to  the production and serving of safer food. Whilst this can often degenerate into a debate about whether an antimicrobial soap needs to be used (in reality their use may often only produce marginally better results) or this product is better than that one, the important thing is that they are used correctly by food handlers AT THE RIGHT TIME.

In summary any food business must strive to achieve high levels of hand hygiene compliance however in recognition that 100% compliance is unlikely they must put in place strategies not only to remove the barriers to hand hygiene but also  to ensure food worker’s hands are as free as possible from contamination  and that hand contact with ready to eat food is minimised.

Answer to the question from  the last article:  How clean is clean?

Depending on the tests, equipment and conditions used, how clean is clean,
is less than 2.5 cfu/cm2 (cfu= colony forming units) and 500 rlu (relative light units).

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