First of all, it is necessary to confirm whether the bird's nest has a musty smell. The normal smell of bird's nest is fishy smell (from marine food), sawdust smell (from the wooden house where the nest is built) and damp smell (from the damp air in the Yanwu).

After food is contaminated by mold and mycotoxin, there are two main hazards: food deterioration caused by mold and poisoning caused by toxin produced by mold. Food contaminated by mold can reduce the edible value of food, or even make it completely inedible, resulting in huge economic losses.

At present, there are about 2 kinds of mycotoxins known. Different molds have different toxic abilities and toxic effects. According to their chemical properties, they can be divided into hepatotoxicity, nephrotoxicity, neurotoxicity, cytotoxicity and similar sex hormone-like effects.