A new, more complete definition of compost was adopted by the American Association of Plant and Food Control Officials recently, after several years of deliberation. Supported by the US Composting Council (USCC), this definition is important, because it re-enforces best practices and quality product standards that have been developed, and differentiates compost from other products often confused as compost, such as biochar, mulch, and anaerobic digestate.
The official definition is:
Compost – is the product manufactured through the controlled aerobic, biological decomposition of biodegradable materials. The product has undergone mesophilic and thermophilic temperatures, which significantly reduces the viability of pathogens and weed seeds, and stabilizes the carbon such that it is beneficial to plant growth. Compost is typically used as a soil amendment, but may also contribute plant nutrients.
The prior definition was: The biological decomposition of organic matter. It is accomplished by mixing and piling in such a way to promote aerobic and/or anaerobic decay. The process inhibits pathogens, viable weed seeds, and odors. (Official 1997)
For more information, visit: https://compostingcouncil.org/blog/news/new-compost-definition-results-from-uscc-work-with-aapfco/