Sanitation and cooking practices have improved over the pass several thousand years. Cross contamination. I can’t see how there’s any reason for that now aside from tradition.
There’s also a reason why foods are more spicy from countries with higher temperatures. Spice is used to retard spoilage and to cover it up.
We don't keep kosher because of "sanitation". That's what the reform Jews use as a human rationale to excuse themselves from following the dictates of the Torah. We were told in the Torah that we can't eat milk and meat together, and with the corollary (Orthodox) rabbinical interpretations, this forms the basis of keeping kosher. It's "tradition" because observant Jews have followed Torah law for thousands of years. That is why there are still recognizable Jews today.