What’s next for plastics?

Is it time to move on? By Grethe Bestbier.

Fruit packaging has evolved dramatically since the early 1970s. How did we get to where we are today, and why is plastic so popular in the fruit industry? Fresh Quarterly spoke to three people at the heart of the packaging business to get a better understanding of fifty years of plastics.

A blast from the past

Plastic packaging wasn’t always the norm. According to Johan Strydom, specialist in fresh fruit supply chains at PS Logistics, before the 1970s fruit was packed and transported without using a single bit of plastic. In those years, all stone fruit was packed in wooden crates, pome fruit wrapped in paper and grapes protected by softwood shavings.

In the 1970s, things started to change. Apples and pears were packed in cartons, followed by grapes and stone fruit by the end of the decade. Fruit was packed at production sites, placed on railway pallets, fastened with rope, moved to so-called ‘fruit shelters’ at the train station and transported overnight to the harbour. Once there, the fruit was inspected and afterwards cooled in cooling tunnels. From the cooling tunnels, the pallets were loaded into the ship with jetty cranes, where the boxes or cartons were stacked by hand, one by one.

In 1978, the first container ships began transporting fruit. Boxes of fruit were now stacked on disposable wooden pallets and plastic straps used to keep cartons in place. Throughout the 1980s, plastic became ever more popular. Fruit was cooled inland. Road transport replaced railway transport. Composite cartons, made from corrugated cardboard, hardboard, and plastic, entered — and later exited — the market. Grapes were packed in plastic bags instead of wrapped in paper sheets. This was followed by polycoat paper bags, carrier bags and modern-day punnets. Apples were packed in plastic bags. Foam sheets were included when packing pallets of apricots to prevent movement of fruits and consequent abrasions. A new age of plastics had arrived.

The wonder of plastic

“The reason for switching over to plastic is a combination of costs, quality and market requirements,” says Strydom. Compared to, for example, a paper bag, plastic is much cheaper.

Cost isn’t the only consideration. The most important benefit of using plastic is the preservation of fruit quality. “You have to manage the moisture content,” says Malcolm Dodd, founder of Coldcubed, a company specialising in temperature-controlled supply chains. “The bag prevents water from leaving the fruit. In the 1970s, fruit that lost moisture in long-term storage and shipping started to lose quality.” Because the atmosphere has a low relative humidity compared to the fruit, moisture tends to move out of the fruit. Plastic packaging increases the humidity around the fruit, limiting water and mass loss.

Fruit packed in plastic bags also retains optimum maturity for longer, since the bag restricts gas exchange. The atmosphere inside the bag is modified due to release of carbon dioxide and uptake of oxygen by the fruit. This prevents overripening. “It plays an incredibly important role in the quality of the produce, particularly when you have very long supply chains,” says Dodd. Plastic packaging such as trays also prevent fruit surface damage due to skins rubbing during shipping.

The last factor driving the use of plastic is the market’s high expectations. “The challenge is to try and change the human mind. People always look for the most attractive, shiniest, brightest, neatest things,” comments Dodd. This includes foods. Sometimes, he says, packaging of food serves little purpose except satisfying the consumer’s expectations. Plastic keeps the product looking good, and without it, food wastage would increase.

The way forward

So is the answer to go back to paper wrappers? Not necessarily, according to Dodd, who explains that it takes a huge amount of energy to create paper – heating, chemical processes, and cutting down trees. Even though paper comes from renewable sources, it takes many years for a tree to grow, while plastics are mainly by-products of the oil industry.

The solution is for the industry to switch over to recyclable and ‘friendly’ plastics. “We don’t want to completely move away from plastic, because if used correctly, it is very beneficial,” says Henk Griessel, quality assurance manager at Tru-Cape. The focus should be to eliminate plastics that can’t be recycled commercially, such as polystyrene, BOPP [biaxially-oriented polypropylene] and PVC [polyvinyl chloride].

“We as the Packhouse Action Group’s plastic workgroup made the decision to still use plastic, but to focus on specific types. We are trying to replace problematic plastic with materials like LDPE [low-density polyethylene] since South Africa’s LDPE recycling is outstanding.” While some countries are moving towards using biodegradable and compostable plastics as well as synthetic waxes, neither is currently mainstream in South Africa – the first due to recycling issues and the second for economic reasons.

Griessel describes plastic awareness in recent years as a movement. The fruit industry is a significant user of recycled plastic and has an important role to play in working towards local and international targets. “The entire world is very plastic-negative,” he says. Luckily, in the fruit industry, there is optimism rather than despair. “I think there is a positive attitude,” says Dodd. “They are very aware of the need to satisfy the consumer demand.”