Is a yellow fruit always ripe?

The answer

No. Color is one clue, but aroma, weight and a slight give under gentle pressure are often more reliable, especially for pineapple, mango, melon and peach. Some varieties stay green or red when ripe, and some fruit is waxed or dyed in commerce, so a bright surface does not always mean quality. Smell the stem end, feel the weight, press gently with the pad of your thumb and use color only to narrow the choice.