Hi,
It would help us other readers to start a new topic for each question; the original topic of this thread is Bluetooth Low Energy.
Concerning Rejsharp’s last paragraph, other reasons to not rely on labels is that some may be wrong unintentionally (such as spoiled milk or undocumented supplier changes), while others may be fraudulent. Also, there may be lab variations — if there are multiple ways to analyze something, you will want the one which is accurate to well under 1%. For food, you have the additional complication of bioavailability.
–Scott.