Low-cost osmotic water-purification sachets could have an important public-health role in less-developed countries where contaminated water supplies are common, conclude authors of a research letter in this week's issue of the Lancet.
A biodegradable two-compartment sachet has been designed for the production of a milk-based therapeutic feed for malnourished children in less-developed countries. This is not infant formula and does not replace the need for breastfeeding.
It contains a semi-permeable cellophane membrane, and is hydrated by osmosis when placed in water, taking about 5 hours for sucrose (contained in the lower compartment) to hydrate to give the required volume. Food can be reconstituted by mixing this solution with the other dry components, contained in the waterproof upper-section of the sachet.
S K Roy and colleagues from the Center for Health and Population Research, Dhaka, Bangladesh, and the Institute for Child Health, London, England, assessed whether these
osmotic sachets could be safely used by mothers or other carers to prepare a therapeutic feed in an urban area of Bangladesh. The aim was to treat severe wasting.
All women received training on how to use the sachets.
|Water-purification sachets safely treat milk supplements in Bangladesh.
31 (89%) of 35 women studied obtained drinking water from a tap and 4 (11%) used tube-wells. All domestic water samples contained bacteria. However, no milk samples prepared using the sachet contained any detectable coliforms. Only 6% of the samples contained heterotrophic ('safe') bacteria.
The sachets were reported as being easy to use, and took an average of 4.5 hours to hydrate.
The investigators comment, "We have shown that mothers in urban Bangladesh can be successfully trained in the use of the osmotic sachets for the preparation of microbiologically-safe therapeutic milk.
"Use of the sachet almost completely eliminated the high bacterial contamination found in normal water supplies in Bangladesh.
"This method could be useful to treat malnourished children at home when preparation of milk-based foods might otherwise not be accomplished safely."
"Our results are applicable to stable situations in Bangladesh, but are not generalizable to emergencies and other unstable situations without further testing," they conclude.