Can carton dent tin’s dominance?

Cans have dominated soups, sauces and broths packaging in the UK. The US and many parts of Europe may be more familiar with selling longer-life savouries in cartons, but in Britain, a carton has generally meant dessert and milk products such as soy milk and custard.

However, change is in the air. Carton volume grew by 3% globally from 20052009 to claim 15% of the packaging market, while cans have held steady with 60%, said Euromonitor in a report published in July 2010.

In addition, carton packaging processors such as SIG Combibloc, which has 35 years of experience in aseptic packaging and provides filling systems, is making significant inroads into the wider liquid food market. Soups and broths, tomato-based products, baby food, cooking sauces and desserts mainly contribute to carton growth, says SIG, which, with big customers straddling canned and carton formats, acknowledges the merits of both forms of packaging.

But, SIG adds, cartons will keep growing in the UK by overcoming years of ingrained consumer preference and effectively conveying their commercial flexibility, efficiency, eco-friendly and space-saving credentials. Euromonitor says the UK features nowhere in the top 10 carton-using countries.

The consumer angle​

Consumers trust cans as the main longer-life ambient package, says Nick Mullen, director of the Metal Packaging Manufacturers Association. "The main thing about canned food is the consumer assumption that when you open a can the food will always be usable, fresh and palatable."

Cartons must try to match that level of consumer confidence.

SIG says its aseptic food packaging uses peroxide to sterilise packs before they are filled. According to tests by the US Food and Drug Administration, this approach has been shown to provide an good pathogen kill rate. The automated filling process minimises human contact and thus possible contamination.

According to Gerhard Kozuschek, global trainer at SIG, its aseptic packaging system is based on the high temperature/short time method, which means that the contents are gently treated by heat before filling.

Cans, on the other hand, are sealed before the food is cooked. The retorting or heating process then sterilises the can and creates a vacuum, which extends shelf-life to over two years, according to Canned Food UK chairman Steve Thomas.

The application of heat in the two packaging approaches does, however, cause some debate. Thomas says sealing before heating retains food's nutritional content and removes the need for preservatives, salt and sugar, beyond taste requirements. However, Kozuschek says by avoiding heating the food through the cartons can equally preserve vitamins and minerals where other more extreme processes would have lost them.

Whatever sealing method is used, the next big issue for cans and cartons is ease of opening. Can manufacturers have responded by creating ring pull systems that eliminate the need for tools. Thomas says new research and development has looked at ways of making them even easier still to open. But he adds that retailers remain unconvinced that consumers will pay more for their slightly more expensive design. However, he says that they are already available in Europe and should start appearing in the UK next year.

Meanwhile, shoppers may still need scissors to open some cartons, but they are traditionally more easy to open than cans. SIG has pursued further improvements, such as launching perforated cartons that allow users to rip off the entire top. These have just debuted in the UK for Tesco's chopped tomatoes and ASDA's baked beans.

Manufacturing advantage​

Manufacturers like the faster fill rates achievable with cans, says Thomas. Speeds can reach over 1,000 cans a minute. In the UK, carton fill rates are about 200 a minute, although higher speeds are reached elsewhere. The difference, claims Thomas, is due to the robustness of cans. "Of all the packaging mediums, we regard cans as the most effective," he says. "The strength also allows them to be handled within the industry: from factory gate to shop shelf."

Cartons may lose out on strength, but they are flexible. SIG's carton fillers allow quick changeover between different-volumed and different products filled with one and the same filling machine. The system allows all filling to take place on one line and, for companies producing the same product under more than one label, sleeves with different printed labels can be pre-selected for filling, says SIG product manager Frank Ludwig.

Thomas claims that flexibility of can production is increasing, offering firms more packaging options as well as robustness. In addition to the typical traditional cylinder, well known to consumers everywhere, manufacturers can now take advantage of square cans, bowls and other customised shapes to fit the requirements of their product. He adds that closing machines have also got better at switching between sizes and shapes.

Environmental matters​

Regardless of materials used, pressure along the food supply chain to reduce energy and packaging waste is growing.

The main benefit of cartons, from an environmental perspective, is their low weight, leading to a lower carbon footprint. SIG's market intelligence manager Magdalena Dzierun says: "Using cartons can save up to 60% of carbon dioxide emissions and fossil resource consumption compared to using food metal cans, glass jars and pouches. The reasons for these results are the light weight of the carton packs, which is due to the resource-efficient use of raw materials."

The shape of the typical carton is also an advantage, she says. Its square shape and recessed pouring spout (if it has one) mean cartons provide excellent shelf optimisation throughout the supply chain, minimising wasted space and reducing transport costs and carbon dioxide generation.

Despite progressive downsizing in the gauge of steel used, cans lose out when it comes to weight and this can result in a higher carbon footprint for their transport.

In 2005 the government, intent on cutting landfill waste, launched the Courtauld Commitment: a voluntary agreement to reduce food and packaging waste, which originally concentrated on its weight. Mullen says that weight therefore became the prime driver for those looking for an easy proxy for environmental benefits.

Even before the Courtauld Commitment, canners realised weight reduction had to be a priority. "The weight of a can has been reduced by over 20% over the last 20 years," says Thomas, adding: "Quite a lot of development has gone into that. But there is more to go."

SIG has considered other green issues aside from weight, leading to the launch of EcoPlus, an aseptic liquid food carton, at the end of August. The new cardboard composite packaging contains more than 80% wood fibre. Its production cuts carbon dioxide emissions by 28% compared with traditional one-litre cartons, according to the Institute for Energy and Environmental Research in Heidelberg.

Both Thomas and Mullen argue that concentrating solely on weight as a measure of environmental impact unfairly distorts the true picture. "It is a superficial move to go from metal or glass to a lighter material. But is it the right thing to do environmentally? You need to look at the total cost and total environmental benefit in drawing up comparisons," says Mullen.

Partly because of these arguments, the Courtauld Commitment 2, launched in March this year, moved away from solely weight-based targets and aims to achieve more sustainable use of resources over their entire lifecycle and along their whole supply chain.

Canmakers, and those using them, sometimes point to the superior recyclability of steel and aluminium. They can easily be sorted in recycling facilities and reused without loss of quality. The difference with paperboard, adds Mullen, is that while it can be recycled it comes out as an inferior product, which eventually has to fall out of the recycling loop.

SIG acknowledges that paper cannot be constantly reused. But it points out that its paperboard comes from Forestry Stewardship Council (FSC) approved sources that assure it as a sustainable, renewable resource.

However, Thomas quotes figures from the Waste & Resources Action Programme, which claim that about 60% of cans are recycled in the UK. He says the amount will increase as collection methods improve. In contrast Mullen points to the comparatively low levels of cartons currently recycled in the UK.

Proponents of both materials can trade off eco-friendly data and there are arguments on both sides. There is also the issue of the huge equipment investment required, should a manufacturer decide to switch from one type of packaging to another. But, ultimately, it will be consumer convenience that decides which dominates in the future. "The market is open to change," says Dzierun. "We've seen a switch by consumers to plastics in certain sectors and are hopeful we will see that same sort of switch with cartons."