Compounds carrying two or more amino groups, including putrescine, spermidine, and spermine, formed in foods during fermentation, ripening, and spoilage. They occur naturally at low levels in all living cells, where they play roles in growth and regulation. In food analysis, rising putrescine and cadaverine in fish or meat signal bacterial decomposition, so analysts measure polyamines and related biogenic amines as objective freshness and spoilage indicators. Fermented foods such as cheese, wine, and cured meats also contain them at levels that reflect their microbial history. Monitoring keeps both quality and the small sensitive-consumer risk from excessive biogenic amines in check.