BIER

In the year of 1516 the Bavarian Reinheitsgebot (pronounced [rine-hites-gebo:t], = purity law) was proclamated here in Ingolstadt by William IV, Duke of Bavaria. It became the German Reinheitsgebot by the way only in 1906 on getting valid for the whole then German Reich.
Thus it is the oldest food law of the world still being effective. It is obligatory for all German breweries.
This is the translation of the most important excerpt:

Especially We order that furthermore
there be not used any other ingredient to brew beer
than only barley, hops and water in each
of Our cities, towns and in the country.
Anyone breaking and not respecting this law
shall be punished by the jurisdiction:
We command that each barrel of this beer
be taken away from the brewer.