"Dithiocarbamates" are a functional group of different pesticides that all contain carbon disulfide (CS2) components as a common characteristic. Most dithiocarbamates act as fungicides, but some are also used as herbicides or insecticides. Common examples of this group are Mancozeb, Maneb, Metiram, Propineb, Thiram, and Ziram. Dithiocarbamates are primarily (though not exclusively) used on fruit and vegetables. Although the use of dithiocarbamates is forbidden in organic farming, all sorts of dithiocarbamates are used in conventional vegetable farming. For the production of fruit, however, there are many differences in terms of what is allowed in which country. In Germany, for example, the use of dithiocarbamates is not permitted on apples and pears. All of the maximum levels that are valid throughout the EU are stated in the Regulation (EC) No 396/2005.
Dithiocarbamates are normally detected and quantified indirectly via the carbon disulfide (CS2) content and as a sum parameter. This means that the individual active substances cannot be identified. Furthermore, the analysis may also lead to false positive results if the plant naturally contains sulfur or carbon-sulfur bonds. This is the case for plants of the mustard family, various types of cabbage, rapeseed, onions, and garlic. There could also be special characteristics in other individual cultures that could lead to false positives. This is known to be the case for ripe papaya fruit, for example, as they can release carbon disulfides as a result of strong enzymatic activity. One other potential sources of contamination could be latex gloves, which are used in the production process, in trade, or when taking samples. In the production of latex gloves, certain additives are used to accelerate the vulcanization process, and these could also include dithiocarbamates.
As part of our routine analysis, the GBA Group tests for dithiocarbamates in a wide variety of food matrices using Headspace GC-MS technology. If you have any questions, we will gladly assist you.