Über unsPesticide Residues in Processed Foods, Mushrooms, Cereals and Potatoes, 2013
Summary of Residue Findings in Conventionally Produced Products
Ellen Scherbaum, Marc Wieland
Analytical Background
Analyses of pesticide residues usually focus on fresh fruit and vegetables. However, processed foods such as deep frozen products, dried fruits and vegetables, canned goods and juices are also consumed in large quantities. Thus, it is important to analyze these products as well. The processing of foods often leads to a reduction of pesticide residues. Nevertheless, the resulting change of pesticide concentration must be taken into consideration when judging whether a product is in compliance with the established EU-wide maximum limits.
Summary
In 2013, in addition to 1,753 samples of fresh vegetables and fresh fruits from conventional production, 344 samples of processed foods, mushrooms, cereals and potatoes from conventional farms were also analyzed for the presence of residues from over 650 different pesticides. 254 of these samples (74 %) contained residues from a total of 153 different substances. Amounts in excess of the MRL were detected in 18 of the 344 samples (5.2 %) (see Table 1), which was lower than the rate of violations from the previous year (7.5%).
| No. Samples | 344 |
| No. w/ residues | 254 (74%) |
| No. exceedances of MRL* | 18 (5,2%) |
| Average quantity of pesticides | 1,05 mg/kg |
| Average quantity of pesticides excluding fosetyl** (sum of fosetyl and phosphorous acid) |
0,30 mg/kg |
| No. substances per sample | 3,0 |
There were large differences between the matrixes in terms of pesticide contamination. The results of the residue analyses of processed foods, mushrooms, cereals and potato samples are presented in Table 2.
| Type of Sample |
No. Samples |
Samples |
Samples w/ Multiple Residues |
Samples w/ |
No. Substances > ML* |
Substances > ML* (Matrix, Origin) |
| Cereal | 7 | 4 (57%) | 2 (29%) | 0 | 0 | - |
|
Cereal Products |
9 | 8 (89%) | 6 (67%) | 0 | 0 | - |
| Legumes | 18 | 16 (89%) | 6 (33%) | 2 (11%) | 2 | pirimiphos-methyl (lentils, unknown); trimethylsulfonium cation (beans, Argentinia) |
| Nuts | 15 | 8 (53%) | 4 (27%) | 1 (6,7%) | 1 | fosetyl, sum (walnuts, USA) |
| Potatoes | 40 | 35 (88%) | 28 (70%) | 2 (5,0%) | 2 | chlormequat (I); DDAC (NL) |
| Vegetable Products | 37 | 29 (78%) | 23 (62%) | 6 (16%) | 39 | DDAC (prepared carrots, Netherlands); All others: 5 x wine leaves (Turkey) acetamiprid (1x); ametoctradin (1x); azoxystrobin (2x); boscalid (2x); cymoxanil (1x); cypermethrin (2x);dithiocarbamate (1x); endosulfan, sum (1x); famoxadone (1x); flufenoxuron (1x); iprodione (1x); kresoxim-methyl (1x); lambda-cyhalothrin (3x); mandipropamid (2x); metalaxyl/metalaxyl M (2x); methoxyfenozide (1x); metrafenone (1x); myclobutanil (2x); penconazole (1x); propargite (1x); pyraclostrobin (1x); pyrimethanil (2x); quinalphos (1x); quinoxyfen (2x); triadimefon/triadimenol (1x); triazophos (1x); trifloxystrobin (2x) |
| Cultivated Mushrooms | 50 | 35 (70%) | 26 (52%) | 1 (2,0%) | 1 | DDAC (oyster mushroom, PL) |
| Wild Mushrooms | 19 | 16 (84%) | 8 (42%) | 3 (16%) | 3 |
DEET (chanterelle, 2x PL, 1x Germany) |
|
Cultivated Mushroom Products |
2** | 2 | 2 | 1 | 1 | fipronil, sum (Mu Err, Vietnam) |
|
Fruit Products |
33 | 27 (82%) | 22 (67%) | 0 | 0 | - |
| Fruit Juices | 34 | 15 (44%) | 5 (15%) | 0 | 0 | - |
| Wine | 39 | 31 (80%) | 28 (72%) | 0 | 0 | - |
| Hop | 2** | 2 | 2 | 1 | 1 | captan (D) |
| Tea | 11 | 9 (82%) | 3 (27%) | 0 | 0 | - |
| Baby Food | 14 | 4 (29%) | 0 | 0 | 0 | - |
| Spices | 9 | 9 (100%) | 5 (56%) | 1 (11%) | 1 | cyromazine (ginger, China) |
| Other | 5** | 4 | 3 | 0 | 0 | - |
| Total | 344 | 254 (74%) | 173 (50%) | 18 (5,2%) | 51 | - |
Detailed Presentation of Particular Matrixes
Grape leaves
Grape leaves, with their multifarious fillings, are a popular and widely used ingredient for dishes in southeast European and oriental kitchens. Because wine and table grapes are often treated with various pesticides, one can expect to find the respective residues in their leaves as well. In 2013 eight samples of grape leaves from conventional production were analyzed for pesticide residues. The grape leaves were either marinated in salt brine in screw top glass jars or were pre-packaged in a vacuum-pack. Seven samples came from Turkey, one was from Greece. Six of the seven Turkish samples contained residues from multiple pesticides and five of them exceeded the valid maximum limit for grape leaves, established in consideration of the many pesticides applied to this matrix. One of the samples exceeded the maximum limit for as many as 18 substances each! This sample contained a total of 37 different pesticides. The sample from Greece presented a completely different story, however – only traces of one substance were found.
The average quantity of residues from pesticides was 4.4 mg/kg; this was much higher than in other fresh fruits and vegetables, where the average has been about 0.4 mg/kg for several years.
Grape leaves are a side product of grape production and are not normally grown as a distinctive culture in and of themselves. As a result, very few applications for special maximum limits for pesticides in grape leaves have been made, the effect of which is that grape leaves are judged by the very low, common MRL established at the lower limit of analytical determination. The producers of grape leaves could apply for higher maximum limits, but the creation of a necessary database for, e.g. the carrying out of pesticide analyses, is time-consuming and expensive. Given that considerably fewer grape leaves are consumed than table grapes and that, in part, the maximum level authorized for pesticide residues is significantly higher for table grapes, occasional cases of MRL exceedance in grape leaves is not considered detrimental to the consumer. Nevertheless, the existing, legally binding maximum limits are to be complied with.
Chanterelle
Chanterelles are wild mushrooms; since they are gathered in the forest and not cultivated, they should not contain any residues. However, residues of the repellent DEET have been detected in chanterelles for years, presumably from the mushroom gatherers who use the repellent on themselves as protection from insects and then transfer the substance from their hands to the mushrooms. The results (Table 3) show that usually only traces of the repellent are detected, although in individual cases the amount has been higher (up to 0.98 mg/kg). The generally accepted MRL is 0.01 mg/kg. However, in accordance with § 68, paragraphs 1 and 2 of the German Food and Feed Code (LFGB) No. 1, an exception can be given to importers to market chanterelles with residues of up to 1.0 mg/kg DEET. This authorized exception is often utilized, as Table 3 shows.
| Land of Origin | Substance | Measurement [mg/kg] | No authorized exception available |
| Germany | DEET | 0,003 | |
| Germany | DEET | 0,035 | x |
| Poland | DEET | 0,047 | x |
| Poland | DEET | 0,009 | |
| Poland | DEET | 0,040 | x |
| Portugal | DEET | 0,026 | |
| Russia | DEET | 0,026 | |
| Russia | DEET | 0,980 | |
| Russia | DEET | 0,009 | |
| Russia | DEET | 0,003 | |
| Russia | DEET | 0,002 | |
| Belarus | DEET | 0,210 | |
| Belarus | DEET | 0,001 | |
| Belarus | DEET | 0,003 | |
| Belarus | DEET | 0,025 | |
| Belarus | DEET | 0,011 |
Quaternary Ammonium Compounds (QAC): BAC und DDAC
Following the detection in 2012 that the bactericidally effective quaternary ammonium compounds DDAC and benzalkonium chloride (BAC) are increasingly found in plant-based foods, investigations continued in 2013. Residues of QAC in quantities above the general MRL of 0.01 mg/kg were found in 3 of the 344 samples (0.9%), a significant improvement over the situation in 2012, where 5.3% of the samples were positive. The results of the investigations are presented in Table 4.
The residues can either be caused by the application of QAV-containing disinfectants used in the processing of foods, such as washing and packing, or via the use of plant strengtheners that contain these substances illegally. According to the Federal Institute for Risk Assessment (BfR), an acute and chronic health risk as a result of the DDAC residues detected thus far is improbable.
| Type of Sample | Country of Origin | Substance | Measurement [mg/kg] |
| Pre-cooked Potatoes | Netherlands | DDAC | 0,37 |
| Oyster Mushrooms | Poland | DDAC | 0,041 |
| Prepared Carrots | Netherlands | DDAC | 0,058 |
Legal Issues: Because no specific maximum limit for residues of QAC was established under EU Regulation No. 396/2005, the general residue limit of 0.01 mg/kg according to Article 18, Paragraph 1b of the same regulation is to be applied. Whether the residues are a result of the application as a biocide or a pesticide is immaterial.
Because many products on the market in 2012 hadn't been marketable, the Standing Committee for the Food Chain and Animal Health (StALuT/SCoFCAH) published guidelines on 13th and 25th July, 2012. If the detected residues are a result of cross-contamination that occurs during processing, a provisional enforcement level is applied until the SCoFCAH has made a decision. This allows for the temporary marketing of products containing DDAC and BAC in amounts that are not a health risk. Plant and animal-based food and feed with a DDAC and/or BAC value of over 0.5 mg/kg should not be marketed, but rather removed from market shelves and safely disposed of. None of the tested samples were found to have exceeded this enforcement level.
Chlorate and Perchlorate
The newly discovered contamination of foods with perchlorate, as well as the problems with the herbicide chlorate, the cause of which is not yet known, is not the subject of this report. Die neu aufgedeckte Kontamination von Lebensmitteln mit Perchlorat sowie die Problematik um das Herbizid Chlorat, deren Ursache noch nicht bekannt ist, sind nicht Gegenstand dieses Berichtes. Analyses of this subject have already been published (see the following Internet report under www.cvuas.de):
- New Discovery: Perchlorate Contamination in Foods of Plant Origin vom 27.06.2013
- Chlorate Residues in Plant-Based Food: Origin Unknown vom 11.03.2014
Photo Credits:
CVUA Stuttgart.