Perchlorate is a naturally occurring and manmade chemical that is present in the environment and occurs in some drinking water systems and in foods. Perchlorate levels may vary widely even within a single food based on where it is grown and the amount of perchlorate in the water.

Between 2008 and 2012, the FDA collected and tested a total of 5,464 food samples for perchlorate and found no overall change in perchlorate levels across foods compared to 937 samples collected between 2005 and 2006. A further analysis of perchlorate levels per year between 2008 and 2012 also found no consistent change in perchlorate levels across foods from year to year.

• Survey Data on Perchlorate in Food: 2005-2006 and 2008-2012 Total Diet Study Results Updated May 2017
• Perchlorate: Questions and Answers Updated May 2017
• Preliminary Estimation of Perchlorate Dietary Exposure Based on FDA 2004/2005 Exploratory Data May 2007 - Peer Review Report
• 2004-2005 Exploratory Survey Data on Perchlorate in Food Updated May 2007
• FDA Collection and Analysis of Food for Perchlorate - High Priority - DFP #05-09 February 23, 2005
• FDA Collection and Analysis of Food for Perchlorate - High Priority - DFP # 04 - 11 December 23, 2003
• Rapid Determination of Perchlorate Anion in Foods by Ion Chromatography-Tandem Mass Spectrometry - Revision 2 April 12, 2005