The Science of Hand Hygiene

Scientific study into the transmission of infection as a result o poor hand hygiene practices is helping us to understand the nature of the problem as well as the steps necessary to combat it. Following are highlights from just a few studies completed over the past decade.

Foodborne illness & causes of foodborne illness

Washington Department of Health 1990-1994

Key Findings;

Cross-contamination 28%
Infected worker 13%
Hand contact 4%
Poor handwashing 32%

1000 foodservice workers personal hygiene habits

U.K. Study - October, 2002

Key Finding;

47% of foodservice workers fail to wash their hands prior to food preparation
39% of foodservice workers fail to wash their hands after going to toilet.

Use of gloves by food handlers

Paulson, D. 1996. Boseman, MT>, Bioscience Laboratories

Key Findings;

Without a prior handwash, contaminant Escherichia coli increased their population numbers when gloves were worn at both 1 hour and 3 hour glove change times.
No significant contaminant microbial growth was observed if effective handwashing was performed prior to gloving.

Residual moisture determines the level of touch-contact-bacterial transfer following handwashing.

Findon, P.G., Miller, T.E. Epidem Infect: 1997

Key Findings;

With dry hands, bacterial numbers transferring to skin, food and utilities on touch contact reduced by 99.8, 94 and 99% when compared to the same hands when wet.

Hand drying: A study of bacterial types associated with different hand drying methods and with hot air dryers.

Redway, K., Knights, B., Bozoky, Z., Theobald, A, & Hardcastle. London UK.
University of Westminster, 1994

Key Finding:

Using towels after washing reduced bacterial counts on the hands by over 42% (paper) and 10% (cotton).
Hot air dryers increased bacterial counts on the hands by more than 500%.
Bacteria were relatively numerous in the airflows and on the inlets of 100% of the dryers sampled.
Staphylococci and Micrococci were blown out of 97% of the dryer nozzles.