Reader Oh Sio Poh wrote in to askST about the common practice in hawker centres of using plastic containers to store hot foodstuff: "Is there a guideline for those containers' lifespan? Does the AVA have a guideline for food safety?"

Food correspondent Rebecca Lynne Tan finds out.

Dr Wong Kwok Onn, director of the regulatory programmes department, regulatory administration group, at the Agri-Food and Veterinary Authority (AVA), says takeaway plastic food containers used at eating establishments, including hawker centres, are meant for single use.

Such containers should not be used repeatedly. They are safe for their immediate intended purpose, but not beyond what they are designed for.

For repeated storage of food, consumers should opt only for reusable plastic food containers that have been specifically designed for repeated use. These containers have the sturdiness, thermal stability and other attributes needed for a reusable food container, he said.

However, these reusable plastic food containers are also subject to wear and tear, and should be replaced when they become discoloured or turn cloudy, or when cracks or heavy abrasions appear.

Consumers are advised to follow the manufacturers' instructions on the proper use of plastic food containers and the suitability of the containers for storage of hot food.

But, if in doubt, do not use plastic food containers to store hot food, Dr Wong said.

For more information on the safe use of plastic food containers, go to www.ava.gov.sg/explore-by- sections/food/food-safety-quality/good-food-safety-practices

Follow Rebecca Lynne Tan on Twitter @STrebeccatan