Some microwavable plastic food wraps may not be suitable for prolonged use in microwave cooking.
In a test simulating actual cooking usage of these food wraps, the Consumer Council has found 2 of the 3 polyethylene (PE) samples to melt and deform after 10 minutes of cooking. The same problem was found in the third sample after 20 minutes.
This could pose risk of contamination of the food if in direct contact with the plastic wrap.
Three other microwavable samples, made of polyvinylidene chloride (PVDC), were found to sustain the heat in the same test without melting.
Nonetheless, when tested in accordance with the Japanese Industrial Standard (JIS Z1707:1997), all of the 16 plastic food wrap test samples were found to be in compliance sustaining heat of 100℃ or the claimed maximum sustainable temperature (up to 110℃ and 140℃).
In an experiment to check their resistance to hot oil, some plastic wrap samples were put to test in heated oil. Under such conditions, almost all samples tested were found to melt and deform.
Warnings against using the wraps with hot oily and high sugar content food were found on some samples. Therefore, consumers should ensure the food is cooled down before wrapping.
In addition to heat resistance, the food wraps were examined for the amount of leachable contaminants and plasticizers. The samples were subjected to different tests for different materials - PE, PVDC and polyvinyl chloride (PVC) - on leachable contaminants. All were found to be in compliance of the respective EU Council Directives.
By and large, plastic food wraps are safe for use but a few sensible precautions is advisable:
- Do not use plastic food wrap in direct contact with oily food or food with high sugar content. Use taller container so as to allow room for separation between the food wrap and the surface of the food.
- Microwavable food wraps are not recommended for prolonged use in high temperature in microwave oven, nor are they suitable for conventional and microwave ovens operating grill function.
- Regardless of the type of food wrap, always ensure the food is cooled down before wrapping. Generally PVDC food wrap is of higher heat resistance than PE food wrap.
The Consumer Council reserves all its right (including copyright) in respect of CHOICE Magazine and Online CHOICE ( https://echoice.consumer.org.hk/ ).