ANSWER
Sri Lanka
No specific regulation stipulates that bamboo charcoal is allowed to be added into mooncake and cookies.
Philippines
According to FDA Philippines, no specific regulation stipulates that bamboo charcoal powder is allowed to be mixed with food.
China
No specific regulation stipulates that bamboo charcoal powder is allowed to be used in food.
Vietnam
No specific regulation stipulates that bamboo charcoal powder is prohibited to be used in food.
Malaysia
Bamboo charcoal powder is not listed under Food Regulations 1985 and Codex standard as permitted colouring substance. Therefore it cannot be added into any food as colouring substance.
Reference
Ministry of Health Malaysia. (2017). Food Regulations 1985.
Thailand
According to Thai FDA, no specific regulation stipulates that bamboo charcoal powder is allowed to use in food products.