First there were food miles and now water footprinting seems to be next in line as consumers take a closer look at the sustainability of the food they buy.



Researchers have worked out that the water footprint of one kilogram of beef is 15,500 litres, while the production of the same amount of cheese uses 5000 litres in its life cycle of production through to managing its waste.



Water footprinting is becoming more important as an environmental management tool, say researchers from Massey University and research organisations from the New Zealand Life Cycle Management.



Centre director Sarah McLaren said the drought had reinforced the need for food producers to account for water use.



She said consumers were becoming concerned about the sustainability of the food they buy, and retailers were acting as "gatekeepers" by scrutinising the environmental impact linked with food products on their shelves.



As a result, producers were being asked to provide information on greenhouse gases, energy use, water consumption and biodiversity, and demonstrate how they were measuring and improving their environmental performance, she said.



Some information was already being labelled, and international companies buying New Zealand products were calling for the information.



American multinational retail corporation Walmart was asking all of its 10,000 suppliers to provide the total water use in their facilities and their water-reduction targets.



Anglo-Dutch consumer goods company Unilever has set itself a target of halving consumer use of water associated with its products by 2020.



McLaren said New Zealand might appear to have an abundance of fresh water, but storage and distribution remained major issues.



"New Zealand trades on its clean, green image, so maintaining high standards of production is imperative," she said.

"We live in a globalised economy with a 'virtual water trade' of around 1000km3/year, so water shortages elsewhere in the world can potentially be compensated by water used in production processes in New Zealand where products are then exported." She said New Zealand could position its exported products for competitive advantage by measuring water footprints and driving improvements.



"The recent drought has reinforced the need to account for water use and also to prepare for a future where there may be less water available for agricultural and horticultural production," she said. The centre is leading research and has a programme for assessing the environmental impact of products along their life cycles from the extraction of raw materials to processing, manufacture, distribution, use and final waste management.



McLaren said farmers and other primary producers needed to be aware of their water use as it contributed to the life cycle of a product.



The centre's partners are Massey University, AgResearch, Landcare Research, Plant & Food Research and Scion Research.