Which of the following is NOT a defect of apples?

Seed stem, commonly referred to as the core or calyx of the apple, is a natural part of the fruit's anatomy and does not represent a defect. It is the central part of the apple where the seeds are housed and is essential for the apple's growth and reproductive processes. In contrast, bruising, sun scald, and scabbing are all conditions that negatively affect the quality and appearance of the fruit.

Bruising occurs when apples are mishandled or dropped, leading to discoloration and softening of the flesh, which can make the fruit less appealing and shorten its shelf life. Sun scald is a condition that results from exposure to excessive sunlight, causing the skin of the apple to become discolored and the flesh beneath to deteriorate. Scabbing is a disease caused by fungal infections that leads to unsightly marks on the skin of the apple, which can affect its marketability. Understanding these defects is crucial for determining apple quality in the commodity market, whereas the seed stem is a normal feature that does not detract from the fruit's value.