Temperature dissociation of liquids in reusable thermoplastic containers-An eco-friendly scald risk?

ABSTRACT

Recent global concern regarding the impact of plastic waste on the environment has resulted in efforts to utilise reusable drink containers. Research is lacking regarding temperature dissociation of drinks in reusable thermoplastic cups. This study aimed to compare the cooling time of two common hot drinks sold at a UK retailer, in the three vessels they are sold; ceramic, disposable paper (with and without lid) and reusable thermoplastic cups (with and without lid). All temperatures were collated from 250 ml volumes of black Americano coffee or café latte in the three different containers. The cooling time was measured every sixty seconds using a standardised digital thermocouple thermometer until a threshold liquid temperature of 43 °C was reached. All experiments were performed in triplicate and temperatures converted to a dimensionless logarithmic scale prior to statistical analysis. Cooling time was significantly slower for lidded cups irrespective of material. Unlidded thermoplastic cups significantly slowed cooling times for both black Americano coffee and café latte compared to ceramic and unlidded disposable paper cups. The growing trend in reusable cups does not in itself pose an increased risk of scald injury. However, we consider that the potentially increased ambulatory behaviour associated with using a lidded rather than unlidded cup may increase scald risk. We propose that further consumer guidance should be disseminated regarding the use of any lidded takeaway container to prevent scalds in both adults and children.