Bleaches fail to meet standards

Most household bleaches would kill fewer germs than expected if they were diluted according to the 1:99 ratio the government suggests, the Consumer Council said yesterday.

The concentration of an active ingredient in the bleaches, sodium hypochlorite, determines how effective they are. The government suggests people mix one part of bleach with 99 parts of water for environmental disinfection. That suggestion is made on the assumption that bleaches contain 5.25 per cent of sodium hypochlorite.

But of 29 brands tested by the council, 21 contained concentrations of sodium hypochlorite less than 5.25 per cent, and would be less effective than expected if they were diluted according to the government's suggestion, the council said.

Three brands contained marginally less sodium hypochlorite than 5.25 per cent, and another 18 had concentrations of only 1 per cent to 4.8 per cent.

Tin Loong Bleach was the one with the lowest concentration of the chemical, the council said. The brand's label did not state what amount of sodium hypochlorite was supposed to be in the mixture.

Some brands contained less sodium hypochlorite than claimed on labels. Poly Clean Bleach contained 3.6 per cent of the chemical, less than its claimed level of approximately 5.9 per cent (plus or minus 0.3 per cent). The company did not respond to a South China Morning Post inquiry.