Are spontaneous mung bean sprouts too long toxic?

Not poisonous, the bottom did not grow small whiskers to be careful. Because that is some treacherous traders with no root chemical ripening toxic. Generally will lose nutrients and moisture, will become old, the toxin is not so, but if put rotten will certainly have harmful substances.

Expanded information:

Methods of their own mung bean sprouts: mung bean nets in a pot or other containers, as needed, pouring in the water so that the water to submerge the beans submerged in plastic or plastic sheet for proper sealing. Plastic sheeting for proper sealing, placed in a hotter place, such as a hot bed! Do not expose them to sunlight! Otherwise the bean sprouts will photosynthesize and turn green! Invitation to change a little water, or beans without oxygen will not germinate, more likely to mold.

Mung bean sprouts are low in calories and high in water and dietary fiber. Mung bean sprouts contain in addition to vitamin C generated in the germination process, but also contains the original beans contained in high-quality plant protein and vitamin B1, vitamin B2, calcium, potassium, phosphorus and iron and other minerals in abundance.

Reference:

Baidu Encyclopedia-Mung Bean Sprout