|Fig. 1: The international Radura logo, used to show a food has been treated with ionizing radiation. (Source: Wikimedia Commons)|
The effect of nuclear radiation on food is largely varied, depends on what is consumed how much. For instance, radioactive iodine decays naturally within weeks, but if ingested it can accumulate in bodies and particularly increase the thyroid cancer of children.  Meanwhile, radiation also helps food safety, as gamma rays, electron beams, and X-rays are used for food irradiation to raw meat and fresh produce.  This report studies what CODEX uses to determine whether food is safe for human consumption, specifically for international trade after radiological emergency.
GLs are from The Codex Alimentarius - Latin for "Food Code". The Codex Alimentarious a set of international standards, codes of practice, and guidelines on food production and food safety. It is created jointly by Food and Agriculture Organization of the United Nations(FAO) and World Health Organization(WHO). Its purpose is to "set standards to protect consumer health and ensure fair practices inthe food trade." Codex standards as of July 2015 have 191 commodity standards, 73 guidelines, 51 codes of practice in subject matter. Codex methods of analysis and sampling, or Codex standards. include contaminants and residues of pesticides and veterinary drugs in foods. Codex guidelines specify principles behind policies in certain key areas. Codex codes of practice specify "the production, processing, manufacturing, transport and storage practices" that are essential for food consumption safety. 
Codex Guideline Levels (GLs) for radionuclide levels are rules for radioactivity in foods for international trade following a nuclear or radiological emergency. The guideline deals with contaminants and toxins in food and feed, and lists the maximum levels and associated sampling plans of contaminants and natural toxicants in international trade. These principles are to help governments in sampling and testing whether foods in international trade satisfy particular specifications. 
The calculation of guidance levels for radionuclide activity concentration in food depends in part on Protective Action Guides (PAGs). PAGs are radiation dose levels to an individual at which protective action should be considered to limit the radiation dose to that individual. PAGs were previously defined in the1982 FDA document as "projected dose commitment values to individuals in the general population that warrant protective action following a release of radioactive material." The exposure to contaminants are categorized into several sectors, such as external and internal exposure. It also specifies priorities when different values conflict with each other. 
© Kye Kim. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 S. A. Rivkees, C. Sklar, and M. Freemark, "The Management of Graves' Disease in Children, with Special Emphasis on Radioiodine Treatment," J. Clin. Endocr. Metab. 83, 3767 (1998).
 C. K. Kao, "Nuclear Technology for Food - Food Irradiation", Physics 241, Stanford University, Winter 2012.
 "Understanding CODEX," Food and AgricultureOrganization of the United Nations and World Health Organization, 2016.
 "Principles For the Use of Sampling Testing in International Food Trade," Food and Agricultural Organization of the United Nations, CAC/GL 03-2013, 2015.
 "PAG Manual: Protective Action Guidesand Planning Guidance for Radiological Incidents," U.S. Environmental Protection Agency, EPA-400/R-17/001, January 2017.