Already on their radar, at least for adding caffeine to drinks:
FDA to Investigate Added Caffeine
It has been reported that Starbucks has much more caffeine than the "normal" coffee we used to drink, combined with much larger cup sizes.
So, from the "give-an-inch-and-take-a-mile" file, circa 2019: FDA regulates Starbucks coffee due to high caffeine content and possible exposure to children, requires a Pre-Market Caffeine Application (PMCA) per coffee blend, per coffee size, to be filed with the FDA each time the coffee is brewed, to ensure compliance with caffeine restrictions. Coffee only available to those over 18 with ID (21 in California). Starbucks closes 1,892 stores, and must install full gas chromatography labs in each remaining store to comply. New York Times claims that this is "sensible regulation" designed to keep children away from deadly and addictive caffeine.