Which of the following foods may contain a naturally occurring toxin?

Apricot kernels may contain a naturally occurring toxin called amygdalin, which can convert into cyanide when metabolized. This is particularly relevant because consuming large amounts of apricot kernels can lead to cyanide poisoning, highlighting the potential danger associated with their unregulated consumption.

While apples do contain seeds that also contain amygdalin, the quantities present in the seeds are much lower than in apricot kernels, and typically, the amount ingested from eating an apple is not enough to pose a threat.

Potatoes can develop solanine, a glycoalkaloid that can be harmful, especially if they are green or sprouted, but the context of the question is about naturally occurring toxins broadly, and apricot kernels are more well-known for this risk.

Tomatoes contain a compound called tomatine, which is toxic but generally only in very large quantities; the levels found in ripe tomatoes are safe for consumption. Thus, apricot kernels stand out as the food that most significantly illustrates the risk of naturally occurring toxins in common items.