Mathew is the co-founder of the Keystone Foundation, a not-for-profit organization based in the Nilgiris South India) for close to 30 years. He is also, the co-founder of Last Forest, the customer engaging institution which provides a market platform for all products that come out from the communities.

Mathew was on the World Board of IFOAM Organics International for 2 terms (2011-2017). He was a member of the IFOAM Participatory Guarantee Systems committee as well as a member of the Executive Committee of the PGS Organic Council (India), which was initiated in 2006.