As a helpful comparable example, the State of Oregon doesn't allow medical alert bracelets in food facilities.
2-303.11 Prohibition. Except for a plain ring such as a wedding band, while preparing food, food employees may not wear jewelry including medical information jewelry on their arms and hands.
That's usually a helpful example. If some states are so intense about jewelry they don't allow you to wear potentially lifesaving medical information, you spending a shift without your necklace seems like a smaller deal.
Alternatively, I've always had a jewelry policy of "if I can't see it, it can't get into the food". So wear it somewhere it can't possibly interact with food or equipment such as a pouch, in your pocket, etc. Funny how some of the strongly held personal beliefs suddenly are less important if you provide reasonable options that are only slightly inconvenient.