Admissible Daily Intake (ADI):
The Admissible Daily Intake (ADI) is defined as an estimate of the amount of a food additive, expressed on a bodyweight basis that can be ingested on a daily basis over a lifetime without appreciable risk to health. "Without appreciable risk" means based on the current knowledge, certainty that no harm will result, even after a lifetime of exposure to the chemical additive concerned. The ADI is usually given as a range of 0-x milligrams per kilogram of bodyweight per day.
Food Additives Regulatory Bodies:
The use of additives is strictly regulated in all countries. The regulatory mechanisms differ in detail from one area to another but all aim to ensure safety by defining what additives may be used, in what amount, in what type of food and based on technological need. Each country has its own set of rules for regulating food additives for example, US FDA Guidelines & Regulations gives the American regulations for food additives. Thus anyone producing and marketing food products in the US must abide by them. India has its own set of regulations under Prevention of Food Adulteration (PFA) Act & Rules. Each country has a set of regulations. When an Indian company wants to export to US, then it will have to follow the US regulations. When it wants to export to Australia, their rules have to be followed. So there might be difficulties trying to follow many sets of regulations.
A group of countries may have a common regulation for example, European Union Directives, which give regulations for countries affiliated to it. This allows free exchange of food products across those EU countries. It avoids confusion because of many different regulations being followed for different countries. For international trade we have Codex, SPS, TBT regulations.
Under the WTO agreements, common regulations have been arrived at for those countries signatories to the agreement and this allows the international trade without much problems. Joint Expert Committee on Food Additives (JECFA), from the Food and Agriculture Organisation (FAO) and the World Health Organisation (WHO), will regulate the food additives usage at international level