'Footprint' of ham sandwich

The student-led project traced the supply chain of a number of high street bakery products, including a sausage roll, a strawberry tart and a ham and tomato sandwich.

They are hoping the results could become part of the 'traffic light' system of food labelling.

Researchers from the University's Food Innovation Project calculated the carbon emissions in each stage of the recipes' production.

They took into account the growth and conversion of wheat grain and livestock to the baking, milling and drying of products, and finally the preparation of each recipe.

The results show the typical high street sandwich or sausage roll has a 'footprint' of between 14 and 34 grams of carbon dioxide (CO2).

Dr Wayne Martindale, from the Food Innovation Project, said: "We're all responsible for accounting for where we buy our food from, food miles, nutritional health and how much energy we use to prepare food."

He believes food-mileage should become part of a product's labelling.

Sheffield Hallam University is currently looking into the use of locally-grown produce in all its food outlets. The University's head of trading services Richard McGloin said: "We want to raise awareness of local food, and reducing food miles is a great way of lessening the university's impact on the environment."

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