How to Test Orange for Adulteration (Citrus Red No. 2, Paraffin Wax, Ethylene Gas)

Oranges are often treated with Citrus Red No. 2 dye to improve the color of the skin, especially in green-tinged varieties, and coated with wax to prevent moisture loss.

1. The Cotton Rub Test (Dye Detection):
Soak a cotton ball in water or liquid paraffin and rub the surface of the orange. If the cotton picks up an orange or red tint, the skin has been artificially colored. Natural oranges will not bleed color.

2. The Scrape Test (Wax Detection):
Gently scrape the skin with a dull knife. If a white, flaky, or powdery substance comes off, it is an industrial or food-grade wax coating.

3. The Stem Inspection:
Look at the stem of the orange. A naturally ripened orange has a stem that is slightly brown and dried. If the orange is bright orange but the stem is vibrant green, it has likely been treated with ethylene gas for artificial ripening.

4. The Water Soak (Chemical Check):
Soak the orange in warm water for 10 minutes. If the water becomes oily or develops a chemical smell, it indicates heavy fungicide (Biphenyl) treatment.