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Hand washing in the food service industry

It is a requirement in the ANZFA draft standard 3.2.2 Food Hygiene Practices that a food handler must, whenever washing his or her hands:

(a) use the hand washing facilitities provided
(b) thoroughly clean his or her hands using soap and warm running water, or other effective means;
(c) thoroughly dry his or her hands on a single use towel or in another way that is not likely to transfer pathogenic microorganisms to the hands.

An earlier draft requirement indicating the use of a nailbrush has been deleted.

In a detailed review which includes 101 references (Dairy, Food and Environmental Sanitation 18 (3) 1998 149-162), Snyder concludes that because of inadequate hand washing by individuals who prepare, process and handle food in the retail food systems, foodborne illness caused by faecal-oral transfer of microorganisms continues to be a problem. Snyder goes on to say that, 'a simple hand washing program that is adequate for preventing the transfer of pathogenic microorganisms must be used. Employees must be trained to use this hand washing program so that the removal of transient pathogenic microorganisms from hands and fingertips is assured, with or without the use of gloves. Employees must be given positive reinforcement and in-service training so that hand washing techniques improve and hand washing becomes habitual.'

By reaching this conclusion Snyder echoes the feelings of earlier workers Horwood and Minch who in 1951 (Food Research 16 1951 133-136) studied samples from hands of food handlers selected at random from 22 public eating establishments in Massachusetts. Horwood and Minch concluded, '... the data justify the conclusion that the hands of food handlers should be kept clean and that they should avoid contact with food wherever possible. ... it is certain, however, that real and lasting progress will not be made until management assumes the responsibility for daily education and supervision.'

But what constitutes adequate hand washing and how many managers are aware of it?

Snyder recommends a 'double' hand washing procedure. This involves using a fingernail brush to produce lather on finger tips, hands and arm surfaces during an initial hand wash. The hands are then rinsed, relathered, without using the nailbrush, by vigorously rubbing together hand and arm surfaces and thoroughly rinsed again, then dried using a large volume of clean, disposable paper towels.

This double wash is recommended when employees begin a shift and after they use the toilet.

A 'single' hand wash procedure that does not require the use of a nail brush is adequate (and kinder to the hands) during normal food handling operations for the removal of most transient pathogenic bacteria acquired by routine hand contact with food. Snyder emphasizes it is the management's responsibility to train food workers and require them to use proper methods of hand washing.

There is no reliable recent data to indicate the incidence of food poisoning in Australia caused by poor hygiene of food handlers. However data from surveys by Davey (Food Technology in Australia 37 1985 453-456) and in the United States by Bryan (Journal of Food Protection 51 1988 663-673) and experimental studies cited by Snyder leave no doubt about the potential of food handlers to be a source of foodborne pathogens.

Snyder notes that nearly all disease-causing microorganisms on the skin can be classed as transients, i.e., they do not normally reside in or on the body. Staphylococcus aureus is the common exception. He reports that transient microorganisms can be of any type from any source with which the body has had contact and are found on the palms of hands, on fingertips, and under fingernails. Pathogens that may be present on the skin as transients include Escherichia coli, Salmonella spp., Shigella spp., Clostridium perfringens, Giardia lamblia, Norwalk virus and hepatitis A virus.

Snyder lists three main ways in which transient microorganisms may attach to hands. These are:

1. by faecal contamination remaining on hands of a person who has used the toilet, changed nappies, or cleaned up after a pet,
2. when contaminated raw products (raw meat, poultry, fish, unwashed fruits and vegetables) are touched or,
3. infected cuts or boils are touched or picked.

While the actual numbers of microorganisms transferred to food in this way may be relatively small, some pathogens and especially viruses have a low infective dose. It must also be remembered that time-temperature abuse of a food which will support the growth of bacterial pathogens will permit an initial low number to multiply to a dangerous level. It is usually a sequence of errors that leads to a food poisoning incident.

Snyder's review focuses on a number of other important issues which need to be understood if hygiene practices in the food industry are to maintain an acceptable standard.

Snyder's final comments bear repeating: 'A successful (hygiene) program requires a committed manager. If management is not concerned about hand washing, employees will not be concerned. Recognition should be given to employees who adhere to personal hygiene principles.'

This is as important in the era of food safety plans and HACCP as it has even been.

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Prepared by Keith Richardson and Beverley George
Food Science Australia
PO Box 52, North Ryde 1670. Tel +61 2 9490 8397 Fax +61 2 9490 8499
Email enquiries@csiro.au