While tropical fruits like pineapples and mangoes have been mainstays in the U.S. for many years, more elusive fruits like the mangosteen are growing in popularity. However, while some tropical fruits can be imported to the U.S. with little fuss, the already-expensive and rare mangosteen sometimes requires special treatment.

The mangosteen is around the size of a clementine, with a purple exterior and white flesh that’s soft, sweet, and a little tart. They are primarily grown in Thailand, but mangosteens from this country must be irradiated before they are imported to America, primarily out of caution regarding a destructive pest called the Asian fruit fly.

The USDA describes irradiation as an "ultra-violet process" that "sterilizes pests and destroys pathogens," and the Asian fruit fly, which could potentially devastate over 400 crops in the U.S., is of primary concern. Mangosteen and some other tropical fruits were banned in America prior to 2007, when irradiation practices became the norm.