Table Grapes – Results from Pesticide Residue Analyses

Report from a day in the lab

Nadja Bauer

 

Analytical Background

Picture of Grapes.Table grapes are loved by children and adults alike, and are available practically the whole year round. Until recently the majority of table grapes sold in this part of the country came from outside Germany. However, the amount of local grapes on offer is constantly growing.

 

From the first budding of the flowers to the final picking and harvesting of the grapes, commercial growers often apply pesticides to protect the grapes from contaminants and illness. For this reason, grapes are now among the fruits that tend to be more contaminated with pesticide residues. Local grapes have often been detected with residues of substances that are not authorized for this particular food crop (indication authorization). In view of this situation, the official food control program analyzed table grapes again this year, with a stronger emphasis on local grapes.

 

Summary

Table grapes from conventional cultivation

During the reporting period of calendar year 2013, CVUA Stuttgart analyzed a total of 123 samples of conventionally produced table grapes from various countries of origin for residues of over 600 pesticides. Grapes grown in Germany comprised 25% (31 grapes) of the samples. Pesticide residues were detected in 121 (98%) of the conventionally produced table grapes (compared to 2012: 98 %; 2011: 98 %; 2010: 96 %).

  • Local samples: the local samples were taken mainly from small producers / direct marketers. All 31 table grapes came from the state of Baden-Württemberg. Two of these samples contained residues in amounts that exceeded the MRL, a low rate of 7% (2012: 21 %; 2011: 16 %; 2010: 15 %).
  • Foreign samples: among the 92 grape samples from countries outside Germany, three (from Italy, Morocco, and Turkey) contained residue amounts higher than the legally established MRL. The rate of exceedance was thereby 3% (2012: 5 %; 2011: 1 %; 2010: 6 %).
  • Unfortunately: one of the 123 tested samples contained the substance methomyl in quantities that exceed the acute reference dose based on young children. This sample was judged to be not fit for human consumption, in accordance with Regulation (EG) 178/2002.
  • Multiple residues: 118 of the 123 analyzed samples (96 %) contained multiple substances per sample. The conventionally produced grape samples contained an average of 7.9 difference substances each, with an average pesticide content of 5.7 mg/kg of grapes (averages in 2012: 7.3 substances and 0.45 mg/kg; 2011: 6.3 substances and 0.55 mg/kg; 2010: 5.5 substances and 0.52 mg/kg). The extreme rise in the average pesticide content is accounted for by the inclusion in 2012 of the substance fosetyl (sum of fosetyl and phosphorous acid) in the investigative spectrum.  Amounts of between 0.028 and 45.5 mg/kg were detected in the analyzed table grapes. When this substance is excluded the average pesticide content is similar to that of previous years, at 0.47 mg/kg.
  • Indication Authorization: substances were detected in nine (29 %) of the local grape samples, whose application in table grapes is not authorized in Germany. These substances included dithianon (3x), fluopyram (3x), folpet (3x) and indoxacarb (3x). A possible explanation for these findings could lie in the difference between the substances authorized for table vs. wine grapes. Support for this argument can also be seen in the fact that, already in 2012, there were no local samples found with substances that are totally banned (for all crops) in Germany.

 

Table grapes from organic cultivation

In this reporting year a total of 26 organically produced table grapes from different countries of origin were analyzed for the presence of pesticide residues, one sample of which came from Germany. In seven of the tested grape samples there were no residues of chemical-synthetic substances detected.  In one sample, however, residues of the quarternary ammonium cation didecyldimethylammonium chloride (DDAC) were detected in the amount of 0.02 mg/kg.  In accordance with Article 5, Paragraph 1, in conjunction with Appendix II and VII of Regulation (EG) Nr. 889/2008 and by implementation of Regulation (EG) Nr. 834/2007 regarding organic/biological production, the application of DDAC in products from organic cultivation is not authorized.  In Attachments II and III of Regulation (EG) Nr. 396/2005 there are no MRLs stipulated for DDAC in grapes.  Therefore, the EU-wide universal maximum of 0.01 mg/kg, as prescribed in Regulation (EG) Nr. 396/2005, Article 18, Paragraph 1/b, is valid.

 

Conclusion

The test results show that conventionally produced table grapes remain unchanged; as in past years, they are among the fruits that carry higher levels of contamination from pesticide residues.  Fully 98 % of the tested table grape samples from conventional cultivation contained pesticide residues. At a rate of 4%, the number of samples that exceeded the MRL was slightly lower than that of the previous year (9%).  One sample from Turkey exceeded the acute reference dose (ARfD; see Info Box, pg.6) based on young children.  Nine of the 31 local table grapes were found to contain residues of substances that are not authorized in Germany for use in table grapes (violation of indication authorization; see Info Box). Substances in amounts > 0.01 mg/kg included: dithianon (3x), fluopyram (3x), folpet (3x) and indoxacarb (3x). Grapes that are treated with pesticides containing dithianon, fluopyram, folpet or indoxacarb, may not be marketed as table grapes for direct consumption.

 

From the 26 organically cultivated table grapes from different countries, 25 fulfilled the requirements for organic cultivation.

 

Info Box

The Difference Between Table and Wine Grapes

The distinction between wine grapes (for the making of wine) and table grapes (for direction consumption) doesn’t seem to be completely understood, especially with regard to locally produced grapes.  Grapes that are sold at market stalls, farmer’s markets, in small grocery stores or in supermarkets for direction consumption are legally classified and judged as table grapes under the food law.

 

The difference is important because, among others, some toxicologically relevant pesticides are only authorized for application in wine grapes, and not for table grapes that will be eaten directly. This is because a large amount of pesticides are removed during the process of making wine, such as pressing, fermentation or purification.  The different levels of maximum residue levels for table and wine grapes thus serve as protection for the consumer.

Detailed Results of Table Grapes from Conventional Cultivation

Illustration 1 shows the current residue situation for all 123 of the tested table grape samples from conventional cultivation. Fully 98% of the conventionally produced table grape samples tested in 2013 contained residues of at least one substance; only 2% were residue free.

 

Illustration 1: Residue Situation in Table Grapes from Conventional Cultivation.

 

Illustration 1 Residue Situation in Table Grapes from Conventional Cultivation (CVUA Stuttgart 2013); R = Residues; MRL = Maximum Residue Limit, in accordance with Regulation (EG) Nr. 396/2005.

 

Table 1 provides an overview of the analytical results. From a total of 123 tested table grape samples from conventional cultivation, five were in violation due to exceedance of the MRL. Two of these samples were locally produced; the remaining three came from Italy, Morocco and Turkey. The cause of MRL exceedance in one of the local grape samples was due to the presence of folpet. The MRL for this substance is 0.02 mg/kg for table grapes, well under that for wine grapes (5 mg/kg). The second local sample contained the substance trimethylsulfonium cation, which is formed as a result of the application of glyphosate.  With a quantity of 0.21 mg/kg it contained significantly more than the legally established limit of 0.05 mg/kg for grapes.  Pesticides containing glyphosate are authorized in Germany for application on table grapes.

 

Table 1: Pesticide Residues in Table Grapes from Conventional Cultivation, by Country of Origin (CVUA Stuttgart, Jan. – Dec., 2013).
  Origin No. of Samples With Residues W/ Multiple Residues Samples > MRL Substances > MRL
Europe

Germany

31 29 (94%) 29 (94%) 2 (7%)

Folpet (1x);
Trimethylsulfonium-Cation (1x)

Greece

2 2* 2* 0

 

Italy

23 23 (100%) 21 (91%) 1 (4%)

Avermectin, Total (1x)

Spain

7 7 (100%) 7 (100%) 0

-

Turkey

5 5* 5* 1*

Methomyl, Total (1x)

Asia
Israel
2 2* 2* 0 -
Africa

Egypt

5 5* 5* 0 -

Morocco

3 3* 3* 1* Dimethoate, Total (1x)

South Africa

14 14 (100%) 14 (100%) 0 -
South America

Argentine

2 2* 1* 0 -

Brazil

10 10 (100%) 10 (100%) 0 -

Chile

11 11 (100%) 11 (100%) 0 -

Peru

5 5* 5* 0 -
 

Unknown

3

3*

3 *

0

-

TOTAL 123 121 (98%) 118 (96%) 5 (4%)  
For Comparison**:
2012 90 98% 89%   9% 10
2011 124 98% 93% 3% 4
2010 138 96% 88% 9% 14
2009 148 100% 93% 16% 35
2008 101 96% 87% 8% 8
2007 128 95% 86% 9% 15
2006 139 96% 88% 10% 14
2005 122 98% 86% 12% 18
2004 138 91% 76% 24% 38


 

MRL = Maximum residue limit, according to Regulation (EG) Nr. 396/2005; * database too small for statistical analysis; **these data only conditionally comparable, as the number of countries differed from year to year.

 

Turkish sample exceeds acute reference dose:

The acute reference dose (ARfD; see Info Box on Acute Reference Dose) for Methomyl, based on young children, was exceeded in one sample of table grapes from Turkey (145 % of ARfD, according to EFSA’s PRIMO Model). This sample was judged to be unsafe and therefore unfit for human consumption, in accordance with Regulation (EG) 178/2002.

 

Info Box

Acute Reference Dose (ARfD)

For the evaluation of plant protector substances that have a high, acute toxicity and that can cause health damage after just a single or short-term intake, the Acceptable Daily Intake (ADI) value is appropriate to only a limited extent. Since the ADI is derived from long-term studies, it is possibly inadequate as a measure of acute risk from residues in food. Therefore, in addition to the ADI value, a further exposure limit has been established, the so-called acute reference dose (ARfD). The World Health Organization defined the ARfD as the amount of a substance one can consume over the period of one day or in one meal without resulting in any discernible health risk. Other than for the ADI, the ARfD value is not determined for every pesticide, but only for such substances that, when taken in sufficient quantities, could cause damage to one’s health even after just one exposure.

 

Source:

"Toxicological reference values for the risk assessment of pesticide residues" Consumption Model For Children: Information Nr. 016/2005 of the Federal Institute For Risk Assessment (BfR) from 2 May, 2005 (www.bfr.bund.de).

 

Table grapes from local production

All 31 table grapes came from the state of Baden-Württemberg and were taken mainly from small producers / direct marketers. Only two of these samples contained residues in amounts that exceeded the MRL, a mere rate of 7%. That means the exceedance rate of local samples has significantly sunken in comparison to previous years (2012: 21 %; 2011: 16 %; 2010: 15 %).

 

Unauthorized Substances:

In addition to checking for compliance with legal MRLs, the monitoring program also includes the testing of local samples to see if the residues resulted from the application of an authorized substance (see Info Box on Indication Authorization). This was not the case for nine (29 %) of the local samples, in which the following substances not permitted for use in table grapes were detected (see Table 2): dithianon (3x), fluopyram (3x), folpet (3x) and indoxacarb (3x). A possible reason for these findings could be the different regulations concerning table and wine grapes. This is substantiated by the fact that there were no substances found that are banned in Germany for all cultures, as was the case in 2012 and 2011.

 

Table 2: Unauthorized Substances in Conventionally Grown German Table Grapes, Compared with Previous Years (CVUA Stuttgart Jan. – Dec. 2013 and 2009-2012).
Year No. Samples Samples with Substances Unauthorized in Germany Samples with Substances Unauthorized for this Culture Substances Unauthorized for this Culture (some cases w/ multiple substances)
2013 31 0 9 (29%) 3x Dithianon,
3x Fluopyram,
3x Folpet,
2x Indoxacarb
2012 24 0 10 (42%) Captan,
4x Dimethomorph,
4x Dithianon,
5x Folpet,
Indoxacarb,
2x Iprovalicarb,
Spiroxamine
2011 19 0 4 (21%) Azoxystrobin,
3x Folpet,
Spiroxamin
2010 39 1 (3%)
Endosulfan
8 (21%) Fluquinconazol,
5x Folpet,
Indoxacarb,
2x Spiroxamine
2009 21 1 (5%)
Oxydemeton-methyl
(ARfD > 100%)
16 (76%) Captan
15 x Folpet (2x ARfD > 100%)
2x Indoxacarb
6x Iprovalicarb
2x Metalaxyl
1x Spiroxamine

 

Info Box

Indication Authorization (§ 12 Plant Protection Law)

The Indication Authorization law has been valid for all pesticides since 1 July, 2001. It states that the substances in question are authorized, but may be utilized only within the scope of application stipulated in the Federal Office of Consumer Protection and Food Safety‘s (BVL authorization databank https://portal.bvl.bund.de/psm/jsp/).

Multiple Residues

Almost all (96 %) of the analyzed table grapes contained multiple residues (see Table 3). The average number of substances detected per grape sample was 7.9.  The type and sheer number of these multiple residues indicates the application of so-called combination compounds as well as various preparations used to combat plant illness or pests.  Due to changes in, expiration of, or simply newly established regulations regarding authorization of substances, the investigative spectrum undergoes constant change.  In order to maintain a good overview of the situation vis-à-vis food contamination it is especially important for official food controllers to continually develop new analytical methods and to discover new substances. The average quantity of pesticides in grapes rose 10 times this year, from 0.45 to 5.7 mg/kg.  This sharp increase can be ascribed to the addition of fosetyl (total of fosetyl and phosphorous acid) in 2012 to the investigative spectrum. An amount of between 0.028 and 45.5 mg/kg was detected in the analyzed table grapes. Without the inclusion of fosetyl, the average quantity of pesticides would have been similar to that found in the previous year, at 0.47 mg/kg. 

 

Table 3: Multiple Pesticide Residues in Table Grapes from Conventional Production, by Year (CVUA Stuttgart Jan. – Dec. 2013 and 2006 - 2012).
Year Average Qty of Pesticide [mg/kg] Æ No. Substances per Sample Maximum No. Substances per Sample Total No. of Different Pesticides Detected
2013 5.7* 7.9 26 95
2012 0.45 7.3 23 81
2011 0.55 6.3 23 84
2010 0.52 5.5 16 83
2009 0.62 5.9 24 88
2008 0.,32 4.0 19 63
2007 0.40 4.7 12 71
2006 0.,48 6.,4 21 82

* The substance fosetyl total was included here; when excluding fosetyl total the average amount of pesticide was 0.47 mg/kg.

 

As Table 4 shows, there is little variation in the average number of substances detected in the conventionally grown table grape samples (between 6 and 8 substances per sample). However, the pesticide content and maximum number of substances per sample can differ by a factor of 3 to as much as 10 when considering the countries of origin.  While, for example, the average amount of pesticides from Asia (2 samples) was 1.1 mg/kg, the local German samples ((including fosetyl (sum of fosetyl and phosphorous acid)) contained an average of 12.2 mg/kg.  In terms of different substances found, the samples from Asia contained a maximum of 7 substances per sample, whereas in a Turkish sample fully 26 different substances were detected.

 

Table 4: Pesticide Residues in Table Grapes from Conventional Production, by Region (CVUA Stuttgart Jan. – Dec. 2013).
  Africa Asia South America Europe (excluding Germany) Germany
Æ No. Substances per Sample 6.1 6.0 7.5 8.6 8.2
Æ Qty Pesticide w/ Fosetyl, Total [mg/kg] 1,7 1.1 4.7 3.2 12.2
Æ Qty Pesticide w/o Fosetyl, Total
[mg/kg]
0.22 0.26 0.63 0.68 0.26
Maximum No. Substances per Sample 10 7 12 26 17

 

As Illustration 2 shows, the frequency distribution of the number of substances per sample is very wide. The top sample this year was from Turkey, with a whopping 26 detectable substances.

 

Illustration 2: Frequency Distribution of Multiple Residues in Table Grapes from Conventional Production (CVUAS Jan. – Dec. 2013).

Illustration 2: Frequency Distribution of Multiple Residues in Table Grapes from Conventional Production (CVUAS Jan. – Dec. 2013). All the mass spectrometrically confirmed values above the limit of detection were included.

 

Spectrum of Investigative Substances

The analyses carried out on conventionally produced table grapes in 2013 revealed residues from a total of 95 different substances. This sharply increased number of detected substances (81 substances in 2012 and 84 in 2011) can be attributed mainly to the constant expansion and adaptation of the spectrum of substances being analyzed, as well as the ever-developing analytical methods. An overview of the substances most commonly found in conventional table grapes in 2013 is presented in Table 5.

 

Fungal diseases pose a considerable problem for grape production. This is also reflected in the spectrum of substances listed below, where 31 of the 50 most common substances (62%) are so-called fungicides, used for the prevention and/or treatment of fungal diseases.

 

Table 5: Spectrum of Substances in Conventionally Produced Table Grapes: 50 Most Commonly Detected Substances and Exceedances of the MRL (CVUA Stuttgart Jan. – Dec. 2013). All the mass spectrometrically confirmed values above the limit of detection were included.

* = Total Parameter; F = Fungicide; I = Insecticide; A = Acaricide; G = Growth regulator.
  Substances No. Samples with Residues Maximum (mg/kg) No. Samples > MRL
1 Fosetyl, Total (F) 78 45.5 0
2 Boscalid (F) 55 1.1 0
3 Cyprodinil (F) 50 0.48 0
4 Myclobutanil (F) 43 0.17 0
5 Fenhexamid (F) 40 2.2 0
6 Penconazole (F) 38 0.35 0
7 Fludioxonil (F) 37 0.27 0
8 Quinoxyfen (F) 32 0.18 0
9 Imidacloprid (I) 30 0.4 0
10 Spinosad* (I) 30 0.2 0
11 Metrafenone (F) 25 0.93 0
12 Dimethomorph (F) 22 0.49 0
13 Spiroxamine (F) 22 0.33 0
14 Fluopyram (F) 21 0.53 0
15 Pyrimethanil (F) 21 2 0
16 Famoxadone (F) 18 0.11 0
17 Indoxacarb (I) 17 0.16 0
18 Tebuconazole (F) 17 0.065 0
19 Cyazofamid (F) 16 0.14 0
20 Fluopicolid (F) 15 0.046 0
21 Kresoxim-methyl (F) 15 0.039 0
22 Methoxyfenozide (I) 15 0.22 0
23 Pyraclostrobin (F) 15 0.28 0
24 2.6-Dichlorbenzamid 14 0.007 0
25 Chlorat (H) 13 0.022 0
26 Iprodion (F) 13 3 0
27 Proquinazid (F) 13 0.056 0
28 Azoxystrobin (F) 12 0.41 0
29 Trifloxystrobin (F) 12 0.32 0
30 Chlorpyrifos (I) 11 0.13 0
31 Spirotetramat, Total* (I) 11 0.18 0
32 Difenoconazole (F) 10 0.17 0
33 Folpet (F) 9 0.079 1
34 Metalaxyl/Metalaxyl M (F) 9 0.15 0
35 Gibberellic acid(W) 8 0.01 0
36 Lambda-Cyhalothrin (I) 8 0.05 0
37 Cyflufenamid ((F) 7 0.02 0
38 Deltamethrin (I) 6 0.026 0
39 Dithianon (F) 6 0.055 0
40 Ethephon (W) 6 0.47 0
41 Iprovalicarb (F) 6 0.014 0
42 Methiocarb, Total (I, A) 6 0.011 0
43 Tetraconazol (F) 6 0.062 0
44 Chlorpyrifos-methyl (I) 5 0.009 0
45 Emamectin (I) 5 0.006 0
46 Tebufenpyrad (I, A) 5 0.028 0
47 Avermectin, Total (I) 4 0..22 1
48 Fenarimol (F) 4 0.006 0
49 Perchlorat 4 0.056 0
50 Spirotetramat-Enol Glykoside, Metabolite 4 0.13 0
...        
  Dimethoat Omethoat Total 2 0.035 1
  Methomyl, Total 2 0.056 1
  Trimethylsulfonium-Cation 1 0.21 1

 

 

Table Grapes from Organic Cultivation

Among the 26 organically produced table grapes from different countries 25 fulfilled the requirements for organic cultivation. Residues from the quarternary ammonium compound didecyldimethylammonium chloride (DDAC; see Info Box) were detected in a sample from South Africa in the amount of 0.02 mg/kg.  According to the EU-Eco-Regulation, the use of DDAC in organically cultivated products is not authorized. Since there is no specific MRL for DDAC in Regulation (EG) Nr. 396/2005, the EU-wide universal maximum of 0.01 mg/kg in accordance with Article 18, Paragraph 1b of this same regulation is applied. Meanwhile, the EU has established an intervention value of 0.5 mg/kg for DDAC (Didecyldimethyl-ammonium chloride); this value was not exceeded by any of the currently tested samples.  DDAC can have various modes of entry, including its purposeful application as a pesticide or via cross-contamination, since it is authorized for use as a disinfectant. Because it is often difficult to pinpoint the source of DDAC residues, the intervention value of 0.5 mg/kg makes it possible to temporarily market products containing less than 0.5 mg/kg of DDAC. This amount is not currently viewed as a health risk.  For more information on this topic, see the Internet article "Residues from Quaternary Ammonium Compounds in Fresh Fruit and Vegetables – Origin and Findings", 03 July, 2012.

 

Among the 26 samples of organically produced grapes, 19 (73%) contained residues; this is relatively high compared to the rate of 42% in 2012.  However, this increase is mainly due to the new inclusion of fosetyl (sum of fosetyl and phosphorous acid) in the investigative spectrum. Fosetyl was found in nine (35%) of the samples. Phosphorous acid acts as a fungicide, whose use as a plant strengthener in organic grape cultivation was authorized until the end of 2013.  Spinosad, an effective insecticide which is permitted for use in organic cultivation in accordance with the EU-Eco-Regulation, was detected in eight of the 19 samples containing residues. These two substances accounted for the residues in 15 of the 19 grapes.

 

Info Box

DDAC – A Quaternary Ammonium Compound (QAC)

DDAC is a quarternary ammonium compound that is authorized in the EU for use both as a pesticide for ornamental plants as well as a biocide for disinfection. DDAC has also been detected in the plant strengthener Vi-Care which, in the meantime, is no longer authorized to be marketed.

 

BAC is a quarternary ammonium compound that is not authorized in the EU for use as a pesticide. A variety of biocide products containing BAC and other quarternary ammonium compounds are currently under review by the EU. BAC was previously a substance/additive in the plant strengthener „WUXAL Aminoplant“; this product may no longer be marketed, however, either as a plant strengthener or as an additive.

 

Cross-contamination can occur by various means.  For example, crops or food can come in contact with surfaces treated with biocide products containing DDAC/BAC.  Similarly, exposure can result from the use of DDAC/BAC for disinfecting washing water for packaging or for irrigation.  Further sources in agriculture can include DDAC/BAC in fertilizers and as byproducts of pesticides.

References:

EFSA PRIMO-Modell.

 

Photo Credits:

CVUA Stuttgart.

 

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Report published on 27.03.2014 15:18:01