Virgin materials are the biggest contributor to the carbon footprint of milk packaging, new research from Wrap has shown.

The study, carried out by environmental consultancy ERM, also found that lightweighting had the biggest effect on cutting a pack's impact, followed by using recycled content.

The report, ‘Life cycle assessment of example packaging systems for milk', looked at the impact of lightweighting and using recycled materials in a range of milk packs including HDPE bottles, cartons and returnable glass bottles.

It concluded that for all three pack types, lightweighting the pack by 10% showed the lowest overall environmental impact.

For glass and HDPE bottles, the waste management option with the lowest carbon impact was recycling; for cartons, the best option was split between recycling and energy-from-waste.

However, it also concluded that the extraction or growing or raw materials and the processing of these into packaging formats was the biggest contributor to milk packaging's carbon impact.

Wrap director of retail Richard Swannell told Packaging News that the findings supported the waste hierarchy of reduce, reuse, recycle.

"This study gives us statistical evidence that, with a life cycle assessment approach, lightweighting and recycling really do show an environmental benefit."

He said that while the study had examined recycled content and lightweighting in isolation, a combination of the two was both possible and desirable as long as the integrity of the pack was not compromised.

The study focused solely on the packaging and did not take into account the carbon impact of the product - an approach for which Wrap has been criticised in the past.

Swannell said: "Of course, the percentage impact of the product is the biggest factor and we will no doubt move towards product assessments."

Milk industry body Dairy UK, whose Milk Roadmap has set a target of including 10% recycled content in all HDPE milk bottles this year, welcomed the findings.

Environment manager Fergus McReynolds said: "Wrap has confirmed that the industry's focus on including more recycled content in plastic bottles is a key strategy for reducing carbon. It validates the Milk Roadmap, which is driving this work forward."