Mineral oil is any hydrocarbon product derived from minerals. It can be divided into food grade and non-food grade mineral oil. Food grade mineral oil, also known as white oil or liquid paraffin, is colourless and odourless. It is used as glazing agent or anti-foaming agent in food processing. The application of mineral oil in food industry is regulated so that its use is limited to specific food processing. Mineral oil is not allowed to be added to hull surfaces of melon seeds for waxing purpose to give them glossy appearance.

Impact on health

So far, no reports have been found about the toxicity of food grade mineral oil. However, consuming too much food that contains mineral oil may cause diarrhoea and gastrointestinal discomfort.

How to reduce the risk of intake of mineral oil?

It is important for both the public and the industry to maintain good personal hygiene at all times and follow the “Five Keys to Safer Food”. In order to reduce the risk of excessive intake of mineral oil from the consumption of melon seeds, one may refer to the following tips:

Safety tips to the public

1.    Purchase Chinese New Year food from reputable shops. Avoid buying food of unknown sources or which is unreasonably cheap;

2.    Avoid buying melon seeds that appear too glossy;

3.    Use a hand cracker when eating melon seeds to avoid any direct contact between the mouth and the hulls;

4.    Do not suck the entire melon seed into the mouth, or lick the hull when taking out the inner part of the melon seed;

5.    Maintain a balanced diet, and do not eat excessive amount of melon seeds at a time.

Safety tips to the industry

1.    Purchase from reliable suppliers, and do not import or produce any melon seeds added with mineral oil;

2.    Retain invoices for source tracing when necessary;