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.
December 2005
Risk Assessment Section
Food and Environmental Hygiene Department
Last
revision date: 16-12-2005