01.04.2014

Detection of chlorate residues in foods

The analytical services of ifp Institut für Produktqualität now also include the detection of chlorate residues in foods by means of LC-MS/MS.

The necessity of chlorate detection was brought to the attention of the food industry by findings recently published by the Stuttgart Investigative Office for Food Control and Animal Health (CVUA Stuttgart).

Chlorates were used as pesticide agents in total herbicides until they were banned in the EU in 2008.  Classification as a pesticide agent, however, means that Article 18 (1)(b) of Regulation (EC) 396/2005 applies, which defines a general maximum residue level of 0.01 mg/kg as the limit value throughout the EU.

So far the source of the chlorate residues cannot be pinpointed, despite extensive research and investigations performed by the food industry. Apart from the illegal use of chlorates as herbicides, which is considered unlikely on such a big scale, the surface disinfection of foods (allowed in the U.S. for instance) is a conceivable source.

According to the latest findings, however, the most probable source of chlorates in food is disinfected drinking water that is used for washing.  When using disinfectants containing chlorines, such as sodium hypochlorite, chlorate ions form as a side-product which may affect the food.

The Stuttgart Investigative Office for Food Control and Animal Health (CVUA Stuttgart) has analysed more than 1,000 food samples of various kinds and origin for chlorate residues since autumn 2013. This showed that approx. 25% of the (non-representative) samples contained chlorate levels exceeding 0.01 mg/kg.