Health: The truth about - killing germs

We all know about the bleach that kills 99 per cent of all known germs. But here comes another miracle product for weary housewives: Microban, a new type of disinfectant, that according to the blurb will enable the kitchen of the future to keep itself clean, with every surface being lethal to any bug that comes into contact with it.

Steps have already been taken towards this vision of a germ-free future. Sainsbury and Marks & Spencer are both planning to sell products such as chopping boards, dishcloths and towel mats impregnated with Microban, which kills 99 per cent of bacteria, including those implicated in food poisoning. The active ingredient, Triclosan, can be bonded into synthetic fibres during manufacture, and its antibacterial properties are constantly replenished (even after washing) as its molecules rise to the surface.

Developed in the United States (of course), Microban can also be used in toys and could in future beincorporated into kitchen surfaces, floors and cupboards. Tests have shown that when a Microban chopping board was infected with E coli 157 (the one associated with minced beef), the number of bacteria fell over 24 hours from 100,000 to 50. On an untreated board they rose to 10 billion.

So is Microban the miracle we have been waiting for? With cases of food poisoning in Britain currently running at about 100,000 annually, it would certainly be nice to think so. But the vast amount of food-borne illness is caused by meat contaminated before it reaches the kitchen; some 40 per cent of poultry is thought to be infected with salmonella, while one study indicates that 22 per cent of fresh beef could be carrying E coli. Food hygiene specialists say the advent of a new disinfectant should not detract from what is really needed to make food safe: a reduction in "bacterial loading" on farms and in abattoirs and food-processing factories.

There is also the danger that the hype surrounding Microban (it "redefines the meaning of the word 'clean' " according to Geoff Spiegel of Sainsbury) will lull people into a false sense of security. Nothing can replace the basic rules of food hygiene, such as storing food sensibly (raw meat at the bottom of the fridge), defrosting it properly, cooking it thoroughly and never letting it hang around at the lukewarm temperatures in which bacteria thrive. Neither can any disinfectant, however powerful, beat a thorough wash of floors, work surfaces and dirty dishcloths with soap and hot water. Keeping things physically clean is crucial, since disinfectant is quickly rendered inactive by large amounts of organic matter, be it food, blood or soil.

While impregnating toys against bacteria is probably a good thing, it will not do anything to reduce the numerous other ways children pick up infections: by sucking the blanket which the cat has just sat on, for example, or forgetting to wash their hands after using the lavatory (and then sucking their fingers).

Some microbiologists believe we can go too far in our quest for total cleanliness: if we are not exposed to a reasonable cross-section of germs, we will never get the chance to develop natural immunity. So there is probably no need to follow the advice of one American health magazine: it told its readers they should always lift the lavatory seat with the toe, and push the flush lever with an elbown Cherrill Hicks