Baden-Württemberg

Die Untersuchungsämter für Lebensmittelüberwachung und Tiergesundheit

Ochratoxin A in Oil Seeds and Nuts – Seldom Present – Investigations from 2012

Ein Bericht aus unserem Laboralltag

Dr. Renate Schnaufer

 

Photo of pumpkin seeds and pistachios.

Summary

In 2012 oil seeds (poppy, sunflower, pumpkin, and flax seeds) as well as pistachios and pine nuts taken from the administrative districts of Stuttgart and Karlsruhe were analyzed at CVUA Stuttgart for the presence of Ochratoxin A (OTA). A total of 89 samples were analyzed.

 

  • There are no maximum limits established at the EU or national level for Ochratoxin A in oil seeds and nuts. For reference, however, the EU-wide maximum limit (ML) set by regulation 1881/2006 for dried wine grapes is 10 µg/kg and for cereals and cereal flour, 3 µg/kg.
  • No Ochratoxin A was detected in the 14 analyzed poppy seed and pine nut samples.
  • Most of the pistachio samples and sunflower seeds were also free of Ochratoxin A (46 of 50 and 11 of 14, respectively).
  • The highest quantities of Ochratoxin A were found in a sample of sunflower seeds, with 20.6 µg/kg and in pistachios, with 12.2 µg/kg.
     

 

These findings show that there is no reason for concern regarding the residue situation.

 

Background

Ochratoxin A is a mycotoxin that is formed from various species of genus penicillium und aspergillus, which are found throughout the world in nature.  When plant-based foods are stored under inadequate conditions, in contrast to the aflatoxin species, toxins can develop, even in moderate climate zones.  OTA occurs almost exclusively in plant-based foods such as cereals, legumes, coffee, beer, wine grapes and their products (e.g. dried wine grapes, red grape juice, and red wine), cocoa, nuts and spices.

The long half-life of OTA in animal and human organisms is problematic. After the consumption of contaminated products the process of eliminating the toxins from the body is very slow.  According to present knowledge, OTA is considered to be especially damaging to the kidneys and is immunosuppressive.  Animal studies have shown OTA to have carcinogenic and teratogenic effects.  The International Agency for Research on Cancer (IARC) has categorized OTA as a probable carcinogen for humans.

Following reports on Ochratoxin A findings in pistachios from California, among other regions, all samples of pistachios, oil seeds and nuts that were to be analyzed for aflatoxin at CVUA Stuttgart in 2012 were also investigated for Ochratoxin A.

A preview of these investigations can be found in the article „Mykotoxine in Pistazien“ (Mycotoxins in Pistachios) from 22 June, 2012.

 

Introduction

Sunflower and pumpkin seeds, as well as pistachios, are favorites for nibbling and eating as snacks.  Especially in East Europe, sunflower seeds are often eaten as snacks on the go.  They are also used in the manufacturing of sunflower oil.  Poppy seeds, on the other hand, are mostly used in pastries and baked goods. Pumpkin seeds are versatile, in that they can be eaten as snacks, made into pumpkinseed oil, and also be used in baked goods.

Pistachios grow on evergreen deciduous trees that can live for hundreds of years, and are botanically categorized as stone fruit.  Because female and male blossoms grow on different trees, pollination and its ensuing fruit can only occur when both male and female trees are on the same plantation, or when branches from the male tree are grafted onto a female tree. Pistachios thrive in dry, desert-like areas.  The biggest pistachio farms are in Iran, the USA and Turkey.  Pistachios usually come roasted and salted, as munchies.  They taste a bit sweet, almondesque, and full-flavored.  Green, unroasted pistachios are used in the production of confectionaries (Mozart chocolates, pralines, or baklava), ice cream, and in sausage products.  Pine nuts are used in Mediterranean, Turkish, and Arabic kitchens for baking, in rice dishes, or just to snack on. 

Because the seeds of Mediterranean pine trees are very expensive, seeds of the Korean pine tree are often imported from Korea, China, and Pakistan.  These Asian pine nuts are easy to recognize for their triangular shape and dark tips. In comparison to the South European seeds, they are less aromatic and contain more fat. They are described as having a bitter, metallic taste and are often reported as causing a serious but temporary taste impairment, which can last from a few days to several weeks.

Opium poppy seeds contain a small amount of opiates. In Germany there are just two types with small quantities of morphine that are permitted to be grown, while in Austria it has long been a tradition to grow opium poppy seeds, and many pastry recipes contain them. Due to high consumer demand for baked goods in Germany, local stores offer poppy seeds imported from other countries, whose morphine content can be very high. The opiates can be rendered harmless, however, during the baking process (more Information: „Mohn im Haushalt richtig verwenden - aber wie?").

 

Results

The following table shows the results for the analyses of Ochratoxin A in the samples:
Ochratoxin A No. Samples No. Samples with Content > LoQ* Average (Samples with Residues) [µg/kg] Highest Quantity Detected [µg/kg]

Roasted Pistachios

45

3 (6.7%)

4.8

12.2

Green Pistachios

5

1 (20%)

0.24

0.24

Sunflower seeds

14

3 (21.4%)

8.9

20.6

Pumpkin seeds

3

2 (66.7%)

3.4

6.0

Pine nuts

10

0

-

-

Poppy seeds

4

0

-

-

Others (4 Trail Mixes, 2 Peanut products, 1 Flaxseed, 1 Nuts)

8

3 (37.5%)

0.34

0.38

*LoQ Limit of quantification Ochratoxin A: 0,4 µg/kg.

 

The results show that OTA contamination of the analyzed products was fairly limited. Only 8 % of all 50 pistachio samples contained OTA. Sunflower seeds were found to have the highest number of samples (21.4%) above the limit of quantification. In contrast, none of the 10 pine nut or 4 poppy seed samples contained OTA. Because only 3 samples of pumpkin seeds were analyzed, it is not possible to make a representative statement regarding contamination with OTA.
The pistachio samples with the highest level of OTA contamination (12.2 µg/kg) came from Turkey. The same sample was also found to contain Aflatoxin B1 und total Aflatoxin (with 6.1 µg/kg and 6.7 µg/kg, respectively); however, the quantity was under the legal levels stipulated in EU regulation 1881/2006 (6 µg/kg and 10 µg/kg, respectively, taking into account recovery and measurement uncertainty).

The pumpkin seeds with 6.0 µg/kg Ochratoxin A originated in China; the sunflower seeds with 20.6 µg/kg came from the Ukraine. In neither of these samples was aflatoxine detected.
So far there has been no maximum limit established for OTA in oil seeds and nuts at the EU or national level. However, according to the official statement from 26 Sept., 2012 regarding the toxicological evaluation of Ochratoxin A in nuts and oil seeds, the National Institute for Risk Evaluation (BfR) does not expect any negative health effects due to the consumption of pistachios containing 12.2 µg/kg of Ochratoxin A or of sunflower seeds containing 20.6 µg/kg of Ochratoxin A.

 

References

  • Wikipedia Online-Lexicon.
  • IARC 1993: International Agency for research on Cancer, 1993. Ochratoxin A (Group 2B). Summaries and Evaluations 56: 489. Lyon, France. http://www.inchem.org/documents/iarc/vol56/13-ochra.html [19.09.2012].
  • Toxikologische Bewertung des Bundesinstituts für Risikobewertung BfR von Rückständen an Ochratoxin A in Schalenobst und Ölsaaten vom 26.09.2012 (Toxicological Evaluation of Ochratoxin A Residues in Nuts and Oil Seeds by the National Institute of Risk Evaluation (BfR), 26 Sept., 2012.).

 

Photo credits:

Pistazien, Sara Hegewald, Pixelio.de, Image-ID= 586731.

Kürbiskernknäcke, w.r.wagner, Pixelio.de, Image-ID= 214046.

 

Bericht erschienen am 13.02.2013 15:25:37

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