Scientists at the University of Manchester examine the lifecycle of sandwiches, finding it has a carbon emission similar to that of 8.6 million cars.
January 26, 2018
by Canadian Packaging staff
Don’t shoot the messenger. We love sandwiches.
But, according to a recent study by scientist at the University of Manchester, sandwiches contribute to global warming in a big way.
The study looked at the carbon footprint of 40 commercial and home-made sandwiches throughout their life cycles, and found the estimated 11.5 billion sandwiches made annually in the United Kingdom, with consumers spending and estimated £8 billion (US$11.3 billion, CDN$14 billion)—according to the British Sandwich Association—was equivalent to annual carbon emissions emitted by 8.6 million cars.
The 40 sandwiches looked at in the study were of different types, recipes and combinations. It also looked at how the sandwiches were made, packaged, transported and stored, and looked at waste produced during production, and general food waste from stale, rotten or outdated sandwiches that are thrown into the garbage.
It did NOT look at the life cycle of the individual ingredients such as the food and land for the grazing cow or pig, energy and land required to produce lettuce or tomatoes or grain and milling used to produce the bread.
To be fair, any study could look at any product and point to its carbon footprint as being high.
But the University of Manchester study did note that not all sandwiches are created equal, as some of the sandwiches examined had much higher carbon footprints than others.
The highest carbon footprints were for sandwiches that contained pork, such as bacon, ham or sausage, as well as those containing cheese or shrimp.
The largest carbon footprint was found in pre-made, prepackaged, all-day-breakfast sandwiches containing eggs, bacon and sausage, which are kept packaged and refrigerated until sold and eaten—with it generating an estimated 1,441 g (3.18 lb) of carbon dioxide equivalent, which is the same as driving a car for 19 kilometers (12 miles).
The smallest carbon footprint was made by the humble ham and cheese sandwich—though Canadian Packaging wonders if that depends on how many slices of each are included in a “typical” sandwich.
The study found that when making sandwiches at home, the carbon footprint of each sandwich roughly halves the carbon footprint.
But what factors determine the carbon footprint?
Ingredients, of course, as fewer items can affect the score, especially when dealing with meat—specifically pork—cheese, shrimp, lettuce, and tomatoes, as those ingredients were determined to individually have the largest of carbon footprints.
According to the University of Manchester research scientists:
The researchers say that by changing recipes—which also implies the changing of consumer choices and tastes—, as well as packaging options, and the reduction of waste could bring sandwich-related carbon emissions by as much as 50 percent.
The British Sandwich Association agrees with the scientists that by overhauling the best-before or sell-by date system could better prevent over 2,000 tonnes of sandwiches in Britain being wasted each year, as the general feeling is that such dates are too conservative as the commercial packing of sandwiches by manufacturers has shown that sandwiches actually are still safe to eat long past the so-called best-before dates.
In most instances, the shorter dates are placed on sandwiches and other food products as a means of protection for the manufacturer and/or brand owner.
The research by the University of Manchester team was recently published in the Journal of Sustainable Production and Consumption.