The most dangerous tradition was harvesting the corn at an exact date every ear regardless of the state of the corn.
Thus they collected unripe corn which when not stored properly would turn bad and mold.
The peasants would still consume this regardless of the taste.
Back then it was believed that this caused Pellagra a devastating disease that caused insomnia, edema, eczema, ataxia, nerve damage, paralysis, mental confusion, diarrhea, lesions, sensitivity to sunlight, lesions, swollen tongue, enlarged heart, psychosis, aggressiveness, hallucinations and eventually dementia (This is like the jackpot of shitty diseases).
Today it is know that it is caused by a lack of proper nutrition in combination with some toxins found in untreated corn.
From wikipedia:
>The traditional food preparation method of maize ("corn"), nixtamalization, by native New World cultivators who had domesticated corn, required treatment of the grain with lime, an alkali. The lime treatment has been shown to make niacin nutritionally available and reduce the chance of developing pellagra.[23] When maize cultivation was adopted worldwide, this preparation method was not accepted because the benefit was not understood. The original cultivators, often heavily dependent on maize, did not suffer from pellagra; it became common only when maize became a staple that was eaten without the traditional treatment.
This disease ravaged the countryside during those times.
(Not sure but this may explain why maize never really caught on as a staple diet in Western Europe as there apparently was an active effort of stopping people from eating corn since they believed they carried this disease.
E-Europe being poor as shit and with rulers who couldn't give a fuck about their people continued to use it.)