Consumer New Zealand (NZ) recently tested the LifeStraw Personal in their Consumer magazine.
This plastic drinking tube uses several types of filters to clean dirty water and was designed for use in the developing world.
A concerned scientist, who believes the product has many shortcomings, brought the LifeStraw to the attention of Consumer NZ.
During testing, the LifeStraw was found to filter out 99% of the E.coli bacteria in the water passed through it.
However, the filtered water still does not comply with safe drinking standards of New Zealand or the World Health Organisation (WHO).
The manufacturers argue that although the water still contained some pathogens, there is increasing evidence that filtered water with reduced pathogen levels is still beneficial.
Poor quality counterfeit LifeStraws were also found to be widely available.