BBC/ July 22, 2004
The US military has devised a way to ensure its troops in battle need
never go hungry - with dried food that can be rehydrated using dirty
water or urine.
The meal comes in a pouch that filters out 99.9% of bacteria and most
toxic chemicals, says New Scientist magazine.
The aim is to reduce the amount of water soldiers need to carry.
The firm behind it says soldiers should only use urine as last resort -
as the membrane can not filter out urea, which in the long term causes
"The pouch - containing chicken and rice - relies on osmosis to filter
the water or urine," the New Scientist Magazine reported.
The liquid passes through a membrane, thin sheets of a cellulose-based
plastic with gaps just 0.5 nanometres wide.
It means only clean water can reach the food, and the bacteria is left
The idea has come from the Combat Feeding Directorate, part of the US
Army Soldier Systems Center in Natick, Massachusetts.
The organisation is also the brains behind the "indestructible
sandwich", which can stay fresh for three years.
A spokeswoman said the dehydrated pouches would reduce the current
weight of 3.5kg for a day's food supply of three meals, to 0.4kg.
But Hydration Technology Inc, in Albany, Oregon, which made the
membrane, warned it is too coarse to filter out urea so soldiers should
only use urine in an absolute emergency.
Engineer Ed Beaudry was quoted by the New Scientist as saying that the
body would not find using urine to rehydrate food toxic in the short
term, but in the long term it would cause kidney damage.