askST: Is this fruit an orange or a grapefruit?

Reader Yeo Eng Chin wrote in to ask about the oranges he bought at supermarkets which "look and taste suspiciously like grapefruits though on the outside, they look like oranges".

He is concerned as he has to avoid grapefruit for medical reasons and added: "Please help to confirm if such fruits are oranges or grapefruits. If indeed such fruits are grapefruits or have similar properties, then I think supermarkets need to label them clearly."

Food writer Wong Ah Yoke answers.

It is difficult to be absolutely sure without tasting the fruit, but judging from the photograph and your description, I would say it could be a grapefruit-orange hybrid.

It could also be a blood orange, which typically has darker red flesh than what is seen in your photo. But blood oranges should not taste like a grapefruit. They are usually a bit more tart than regular oranges with a slight berry-like flavour.

I would suggest you not eat it if you have been advised by your doctor to avoid grapefruit.