The correct term is TVB-N, volatile salt nitrogen, which refers to alkaline nitrogen-containing substances, such as ammonia and amines, that are produced by the decomposition of proteins during the spoilage process of animal foods due to the action of enzymes and bacteria.

These substances are volatile, and the higher their content, the more amino acids are destroyed, especially methionine and tyrosine, so the nutritional value is greatly affected. It is the main indicator of the freshness of raw fish and meat.

Expanded Information:

Volatile Salt Nitrogen is volatile, and the higher the content, the more amino acids are destroyed, especially methionine and tyrosine, so the nutritional value is greatly affected.

The higher the volatile salt nitrogen, the lower the nutritional value. If the volatile salt nitrogen exceeds the standard, it indicates that the product has begun to rot, and if you continue to consume it, it may cause gastrointestinal discomfort and other symptoms, and in serious cases, it may lead to food poisoning.

Baidu Encyclopedia-Volatile Salt Nitrogen