The Food and Environmental Hygiene Department (FEHD) together with the Consumer Council conducted a joint study on disposable plastic containers for take-away meals. The study aimed to address food safety concerns with respect to the consumption of foods that are contained in the containers, and to determine the suitability of the use of such containers for holding foods under different conditions.
2. Plastic materials commonly used for manufacturing disposable food containers and their lids include expanded polystyrene (EPS), polypropylene (PP), polystyrene (PS) and, to a lesser extent, polyethylene terephthalate (PET). The primary concern on their use is the migration of chemicals, including heavy metals, residual styrene monomers and other substances such as additives for the production of plastics, into the foodstuff.
3. Thirty disposable plastic containers together with their lids, making a total of 50 samples (container and lid were joined together in 10 samples), were collected from different food establishment and school lunch box suppliers in September 2005 for testing of the food safety parameters of heavy metals and residual styrene monomers. Another 30 different disposable plastic containers / lids were collected for suitability testing by measuring the overall migration from the materials into food simulants under different test conditions. The laboratory analyses were done by the Food Research Laboratory of FEHD. References were taken from standards and testing methods established in the Mainland and by the US Food and Drug Administration.
4. Results showed that all the disposable plastic container samples met the safety standards for heavy metals and residual styrene monomers. Hence, with the proper use of disposable plastic containers, it would unlikely cause a food safety problem. Regarding the overall migration tests, most of the plastic materials being tested met the overall migration limits under different testing conditions. In only one PS container sample, when the test condition simulated that it contained fatty foods at a temperature of 120oC, the overall migration exceeded the limit. However, when the test condition changed to simulate that it contained fatty food at a temperature of 100oC, the overall migration of this sample met the respective standard.
5. Despite that most of the EPS, PS and PET samples could meet the migration standard for temperature as high as 120oC, taking into account issues such as physical deformity, these materials are considered not suitable for holding food at temperatures of over 100oC.
6. In the selection of suitable plastic food containers, factors that should be taken into account include the characteristics of food to be contained, such as whether the food is fatty, oily or acidic, the temperature of the food and the duration of contact. To use plastic containers for holding food with temperatures of over 100oC, containers with relatively better heat resistance properties, such as PP plastic containers, should be considered, otherwise, the food should be cooled down before putting into the plastic containers or containers made from other heat resistant materials should be used.
Risk Assessment Section
Food and Environmental Hygiene Department
For the study report (only available in Chinese), please click the following website:
"Disposable Plastic Containers for Take-away Meals (Chinese version)"