The Consumer Production Commission (CPC) under the Executive Yuan has recently renewed a call for convenience stores to follow a voluntary labeling system that nationwide coffee stores have adopted since August 2006 after they agreed with the CPC's proposal of use the colors red, yellow and green to denote different levels of caffeine content.

CPC official Liu Ching-fang explained Friday that the three-color system was formed based on research by the EU Scientific Committee on Food, which suggests that caffeine consumption of under 300 mg per day will not be harmful to the health.

Under the system, the green label marks a caffeine content of under 100 mg, while yellow represents a content of between 100 mg and 200 mg, and red signals more than 200 mg of caffeine, Liu said.