Compostable single-use food service items
Are you being served? An examination of chemical risks posed by compostable single-use food service items.
The NSW single-use plastic actions have restricted the supply of many single-use plastic food service items. At the same time, to stop food waste going to landfill, NSW has introduced a statewide mandate for Food Organics and Garden Organics (FOGO) recycling. As a result, some food service businesses have chosen to supply exclusively compostable, single-use food service items, intending to co-collect them with food waste and send them to commercial composters. However, these items are not currently approved as inputs for commercial composting.
To assess their suitability for composting, a range of ‘compostable’ food service items was collected and tested for contaminants such as per- and polyfluoroalkyl substances (PFAS), phthalates, plastics, and metals.
High concentrations of PFAS were found in many bagasse items, and several products used non-compostable plastics in their lids, linings, inks, and adhesives. These findings support the EPA’s approach and current restrictions on FOGO inputs.
Further research is currently underway to ensure the approved compostable FOGO bin liners are fit for purpose to enter commercial composting facilities.
The NSW single-use plastic bans have had an impact on the abundance of plastic single-use food service items. While the plastic bans were intended to shift business towards reusable items, in many cases, businesses have instead switched from conventional single-use plastic items to certified compostable single-use alternatives.
At the same time, the NSW EPA has been trying to maximise the collection of food organics for composting to minimise food waste in landfills. To operate more sustainably, several commercial operations have designed their food courts to support the joint collection of food waste and compostable packaging. However, none of these food service items are currently accepted as inputs into commercial composting facilities.
The composition and suitability of compostable food service items were evaluated as feedstocks for producing high-quality compost.
Items were collected from manufacturers, businesses, and food courts that intended to supply exclusively compostable products, with a subset of these items selected for further chemical testing. Items were selected to represent a broad range of food service items, including straws, bags, napkins, sandwich wraps, bowls, plates, clamshells, cups, lids, and cutlery. These were made from a variety of materials, including paper, cardboard, bagasse, plastic-lined paper, and wood.
Samples were tested for contaminants such as PFAS, phthalates and metals, with additional testing performed to examine the likely compostability of materials used, including coatings, linings, adhesives, inks, and dyes.
The contaminants detected were found to be dependent on the material type and the source of the material itself.
PFAS was detected in 17 of the 46 items tested, with the highest concentrations and most frequent occurrence found in bagasse products, such as the fibrous single-use bowls commonly used by takeaway restaurants. PFAS is typically added to these items to provide water and grease resistance, giving them plastic-like properties.
Plastic lined items already have plastic properties, so it was unsurprising that none of the 8 plastic-lined samples tested contained detectable levels of PFAS.
In addition to finding PFAS, of the 13 plastic-lined items examined, 9 were found to be lined with conventional non-compostable plastics such as polyethylene. Most sealed containers were also supplied with non-compostable plastic lids, and many items contained non-compostable plastic inks, dyes and adhesives.
Lower levels of contaminants were found in items made from recycled materials. For instance, some items made from recycled cardboard contained low concentrations of metals (e.g. lead, tin, and nickel), phthalates and PFAS.
The findings of this study highlight the value of adopting a precautionary regulatory approach.
Currently, the EPA has limited FOGO inputs to food organics, garden organics, fibre caddy liners, and certified compostable kitchen caddy liners that meet AS 4736-2006. These strict input limitations enable NSW’s commercial composters to produce high-quality composts that pose minimal risk to the environment and human health.
The physical and chemical risks identified in this research have prompted further research into the properties of currently permissible fibre and AS 4736-2006-certified compostable plastic kitchen caddy liners. This upcoming piece of work aims to ensure that the permissible caddy liners are fit for purpose to enter commercial composting systems and, ultimately, the environment.