%K Pesticide residues, contamination, organic food, feed, Organic HACCP, prevention strategies, Qualitätssicherung, Contamination
%L orgprints5413
%T Beurteilung von Rückständen auf Bioprodukten
%I Research Institute of Organic Agriculture (FiBL), CH-5070 Frick
%X Bioprodukte sind nur so gut wie die Umwelt, in der sie produziert werden. Gewisse Rückstände von chemisch-synthetischen Pestiziden sind somit auch in einem biologisch produzierten Lebensmittel zu erwarten und zu akzeptieren.
Bioprodukte stehen aber gut da. In allen Untersuchungen zu Pestizidrückständen auf Bioprodukten im Vergleich zu Produkten aus anderen Anbausystemen werden geringe Rückstandsmengen oder keine Rückstände nachgewiesen.

%X State of the Art:
Pesticides: The uptake of organochlorine pesticides (OCP) into plants is influenced by several factors/parameters. In a comprehensive literature study of Werkbüro für Boden und Bodenschutz (1998) the results of many field, pot and lysimeter experiments were reviewed. The group of OCP is generally highly persistant in soils and can still be found nowadays after it has already been banned for 20-30 years. Within the group of OCP the stability ascends in the sequence Gamma HCH – Aldrin, Dieldrin, Endrin - Chlordan – DDT, HCB. In the group of the HCH-Isomeres Lindane (Gamma HCH) has the highest mobility. Aldrin is degraded into the epoxid Dieldrin. However, further contamination of groundwater by Dieldrin has not been observed. Both Aldrin and Dieldrin have been applied as insecticides in horticulture, fruit and arable crops.
Soil properties: In general no correlation was found between soil content and crop content of OCP. There was found a very broad range of transfer factors (content crop/content soil), ranging from 0 to 86, but mostly between 0 and 1 (Werkbüro für Boden und Bodenschutz, 1998). A high content of soil organic carbon enhances binding of OCP (Beestman et al., 1969; Gonzalez et al., 2003; Harris and Sans, 1971). No relation was found among the soil parameters cation exchange capacity, iron and clay content and plant uptake (Werkbüro für Boden und Bodenschutz, 1998). 
Plant species: The uptake of OCP varies among different plant families. The results of several studies are not consistent. Vegetables from the family of the Cucurbitaceae (e.g. cucumbers, zucchini or pumpkins) accumulate to a much higher degree than root crops such as carrots, radish, or celariac, and sugar beet (Werkbüro für Boden und Bodenschutz, 1998) tomatoe (Gonzalez et al., 2003) and potatoes (Miglioranza et al., 1999). Plants with higher content of lipids or oils (pumpkins, carrots, cress) accumulate such pesticides in a higher amount because of their adipose structures (Mandl and Lindner, 1999; Topp et al., 1986). A transfer depending on the variety was found with carrots (Endrin; Hermanson et al., 1970) and rape (Lindan; Schlosserova, 1994).
Definition of the problem:
Background: Organochlorine pesticides (OCP) such as Dieldrin and DDT were applied world wide against pests in horticulture, fruit and arable crops. Although OCP are forbidden since more than twenty years in the European Union (EU), the highly persistent compounds are still detectable in soil. Several crops are known to accumulate OCP in edible parts up to critical levels. For instance Dieldrin is detected in high economic value crops such as cucumbers (Cucurbitaceae) and tomatoes (Solanaceae). Besides plant type and climatic conditions, soil properties, e.g. pH and soil organic carbon content influence the plant’s OCP uptake. In particular in premium food and feed stuff production, such as organic farming according to EU Regulation (EEC) No. 2092/91, consumer expectations in safe, high quality food are extremely high. Since organic farming is prospering – more than 10% of vegetable production is certified organic in Switzerland – the OCP residues in organic food stuff have become a major issue for food control authorities. Enquiries showed that some of the imported food from EU countries such as pumpkin seed and oil was highly contaminated with OCP. Hence, the OCP problem in food stuff is expected to occur EU wide or even world wide.

Preliminary study: Facing this problem we performed a case study and analysed the OCP content of 15 fields and their grown fruits from the most important Swiss organic cucumber growers. Two out of these 15 field soils revealed Dieldrin leading to surpassing of the tolerance level. It also occurred that the whole crop yield from an OCP contaminated field was rejected by food retailers and the crop had to be ploughed down. The Swiss organic label organisation has the option in their standard now to exclude polluted soils for production of highly OCP accumulating vegetables, but this may severely affect the grower’s economy.

Objectives: In this project we aim at developing sustainable safe food production on OCP contaminated soils, which is economically and ecologically sound.

First we will perform an in-depth field survey on 50 sites to assess the extent of OCP contamination on Swiss farms. Soils and Cucurbitacea crops will be analysed for OCP. Cucurbitacea are chosen because crops of this family accumulate strongly OCP and thus are suitable as indicator plant.

Second, we will develop strategies in bioassays in the glasshouse to lower OCP uptake from the contaminated field soils through immobilisation of OCP by organic carbon addition to the soil and by selection of OCP excluder plant varieties.

These experiments are organised as follows:
i) Test system optimization: We will optimize a previously used test system for the immobilisation and exclusion experiments (see below). We will grow cucumbers in OCP contaminated field soils (little, medium, high) and measure OCP in the growing cucumbers in a time course. As an alternative we will use cress as a test plant to shorten the duration of the experiment. 14C-labelled Dieldrin will be used to calculate fluxes in the soil-plant system. Based on the results of these experiments we will decide which soil and crop we will use in the following tests and when the test plant will be harvested for OCP analyses.

ii) Immobilisation of OCP by organic carbon: The aim of these experiments is to immobilise OCP in the soil by the addition of organic carbon to the soil. The hypothesis is that the OCP will be bound by the organic carbon and consequently the bioavailability is expected to be decreased. Organic carbon will be added to the soil in form of compost or as brown coal product (charcoal) at three levels each. The bioavailability of OCP will be assessed by measuring these molecules in the plant shoot.

iii) Exclusion of OCP by crops: The aim of these experiments is to identify plant varieties with a low OCP uptake. Since cucumbers are normally cultivated by grafted plants nowadays, where a robust and vital root stock is inoculated by a desired variety, we will select for OCP excluder root stocks. For cucumbers, root stocks from the groups of Cucurbita moschata x C. maxima, Sicyos angulatus and Cucurbit ficifolia are currently in use, but we will test further ones from the same family. The root stocks and the grafted plants will also be cultivated in contaminated field soils and OCP will be measured in the plant’s tissue. The most promising treatments from the immobilisation and the exclusion experiments will be applied in combination.

Finally we synthesize the results from the field survey and the glasshouse experiments and, including literature findings, we suggest field evaluations of the elaborated strategies for safe food production on OCP contaminated soils. We already expect after three project years a high degree of applicability of the strategies, since this project bridges basic and applied research and combines different strategies to prevent plant uptake of the harmful OCP.
Project aims including target group:
In the literature and in practice, several solutions for minimizing the uptake of OCP into plants are proposed. Techniques like the removal of contaminated soils and replacement with clean or ameliorated soils are heavily invasive and costly and therefore applicable only on restricted areas. In this project, the following two strategies are envisaged to exclude OCP uptake by the plant:

•	Binding OCP to soil compounds:
A field study carried out in Austria used activated charcoal to reduce the bioavailability of HCB in the soil. Due to the binding of the highly lipophilic HCB onto the carbon surface, it is no longer available for the plant. This methodology reduced the amount of HCB in pumpkin seeds by about 30% (Mandl and Lindner, 1999).
•	Use of exluder plants
Since tomatoes and cucumbers are very often cultivated by grafted plants, where a robust and vital root stock is occulated by a desired variety, one can select for excluder root stocks. For cucumbers, root stocks from the groups of Cucurbita moschata x C. maxima, Sicyos angulatus and Cucurbit ficifolia are currently in use (Lee, 2003). Also with heavy metal contaminations gentle remediation techniques such as the use of excluder plants were performed (Gupta et al., 2000). 
The target group includes farmers.
Methodology:
The basic principles of binding and immobilising OCP as well as exclusion of OCP techniques are known and developed to a certain extent with heavy metals. They are hardly applied under practical farm condition with other organic pollutants such as OCP. The innovation of the project is the near to practice testing condition, the use of the grafting technique to exclude OCP by selected root stocks and the combination of binding/immobilising and exclusion to solve the OCP problem situation.
Accordingly, the project is organised in six work packages (figure 1). In WP 1 we will perform an in-depth literature study (WP 1) as a base for a detailed planning of a field survey on OCP (WP 2). The project follows consequently a “fork to field” approach and starts with the field survey, in order to clarify the degree of OCP contamination in Swiss soils and the edible plant parts of grown Cucurbitacea. After the optimization of a previously used test system (WP 3) the two basic strategies are investigated under near farming conditions in the glasshouse (WP 4 and 5). Finally, we synthesis the results from the field survey and the glasshouse experiments and suggest a field evaluation of the developed strategies to solve the OCP problematic in WP 6.
For all pot experiments in WP 3-5, OCP contaminated field soils will be used as potting ground and cucumbers (Cucumis sativus L. var. Aramon RZ), or alternatively cress (Lepidium sativum L.) will be grown on these soils. Pot size will usually be 5 Liter. Each treatment will have four replicates. 
The following OCP will be measured in soil and plant: Aldrin, alpha-Endosulfan, beta-Endosulfan, Brompropylat, Captafol, Captan, cis-Heptachlorepoxid, Endosulfansulfat, Endrin, Heptachlor, Hexachlorbenzol, Lindan, p,p’-DDD, p,p’-DDE, p,p’-DDT, Pentachloranilin, Quintozen, trans-Heptachlorepoxid with special focus on Dieldrin. The method used for analysis of organochlorine pesticides in soil and plants has been modified from DFG-Multimethode S19 (Anonymous, 1991) and Methode L 00.00-34 (Anonymous, 2001). Soil and plant samples are extracted using a Dionex ASE 200 with acetone : hexan (65:35 v/v) and ethylacetate : cyclohexan (1:1 v/v), respectively. Extracts are subfractionated by silica gel chromatography as described by Metcalfe and Metcalfe (1997). A capillary gas chromatography equipped with a massspectrometer is used for detection of the compounds.
Data sets of the field survey (WP 2) will be analysed by multiple regression analyses. Data of WP 3-5 will be analysed by an analysis of variance, followed by a Tukey test.
Results, conclusion, state of the art:
The project has started in June 2005. So far a monitoring of various agricultural sites with organic and non-organic cucumber production has been carried out. Soil samples of defined areas and cucumber samples for those areas were taken. The analysis for organochlorine pesticides will follow in the next few weeks.
%I Research Institute of Organic Agriculture (FiBL), CH-5070 Frick
%L orgprints5414
%T Safe food production on soils contaminated with organochlorine pesticides
%K Organochlorine pesticides, residues, food contamination, cucumber, soil manipulation, organic carbon, excluder root stocks, Qualitätssicherung, safe food, Biohortikultur

%X Organochlorine pesticides (OCP) were once applied world wide but have been banned meanwhile in most countries because of their ecotoxicity, bioaccumulation and persistence. However, residues can still be present in soils even many years after applications have been stopped and taken up by crop plants. OCP accumulation from bound residues was found to be a particular problem in Cucurbitaceae plants. Two soil surveys performed in 2002 and 2005 in Switzerland revealed that OCP residues were taken up by cucumbers grown in soils that have been converted to organic production in the meantime. Even if legal tolerance values are not exceeded, this is a serious economic problem for the farmers affected by contaminated crops, because consumers of organically grown crops are only willing to pay the higher prices for these than for conventional products because they are particularly concerned about health and environmental quality and therefore expect pristine food. One approach to address the problem would be to increase the capacity of affected soils to bind OCP residues in order to prevent their uptake by the crops. In this study, we wanted to test the potential use of activated charcoal (AC) for this purpose. In addition, we wanted to assess the possibility of using OCP sorption in soil by Tenax® beads as a predictor for the phytoavailability of these compounds to cucumbers. 
We performed two pot experiments in which the cash crop cucumber (Cucumis sativus L.) was grown in soil with bound residues of dieldrin (70 µg/kg), pentachloroaniline (<0.01 µg/kg) and p,p-DDE. The soil was taken from a field under organic farming in which these residues were found in the 2005 survey. In the first experiment, cucumbers were grown for 12 to 13 weeks (until fruits were ripe) in soil into which AC had been mixed at concentrations of 200, 400, and 800 mg/kg and in untreated controls. In the second experiment, Tenax® beads were added to the soil and cucumbers, grown with and without AC amendment (800 mg/kg soil), were harvested after 4, 8, 10, 11, 12, and 13 weeks. 
Dieldrin was the only pesticide detected in the sampled cucumbers and extracted from soil by the Tenax beads. Dieldrin concentrations in the cucumbers were significantly reduced in the treatments with 400 and 800 mg/kg AC. Also significantly less dieldrin was sorbed by Tenax from the soil amended with 800 mg/kg AC than from the untreated control soil. More dieldrin was found to be sorbed by Tenax in the last 3-4 weeks of the experiment, particularly in the control soil, but this trend was not significant. The correlation between the amounts of Tenax-sorbed dieldrin and dieldrin accumulation in the cucumber fruits was significant in control soil and 800 mg/kg AC soil. Hence, Tenax appeared to be suited for the assessment of dieldrin solubility in soil and of phytoavailability to cucumbers.
%D 2007
%K Lebensmittelqualität, Qualitätssicherung, Contamination, Activated charcoal, cucumber, dieldrin, phytoavailability, Tenax
%L orgprints13424
%T Soil amendment with activated charcoal can reduce dieldrin uptake by cucumbers
%A Isabel Hilber
%A Lea Vogt
%A Gabriela S. Wyss
%A Paul Mäder
%A Rainer Schulin

%D 2007
%K Lebensmittelqualität, Qualitätssicherung, Contamination, organic farming, Organochlorpestizide, Organochlorine pesticides, food control
%L orgprints13422
%T Organochlorine pesticide residues assessed in a greenhouse survey in 2005 and a concept of bioavailability experiments
%A Isabel Hilber
%A Gabriela S. Wyss
%A Paul Mäder
%A Rainer Schulin
%X Organochlorine pesticides (OCP’s), such as dieldrin or DDT, were applied world wide against pests in horticulture, fruit and arable crops. Although OCP’s were banned 20 years ago, they still persist in soils and are taken up by the plants (Mandl and Lindner 1999). OCP residues in soil, for instance dieldrin, has been detected in high economic value crops (Wyss et al., 2004) such as cucumber and pumpkin (Cucurbitaceae), which strongly accumulate OCP in their fruits. Consumers generally expect that food is safe and uncontaminated, but those who buy organically grown products are particularly concerned about health and thus sensitive to food quality. Therefore, OCP residues in organic food stuff have become a major issue not only for food control authorities, but also for organic farming labels.

%K Lebensmittelqualität, Qualitätssicherung, Contamination, Ökologische Lebensmittel, GVO, 
%D 2006
%P 1-15
%L orgprints8680
%T Strategien im Umgang mit Kontaminationen im Unternehmen
%A Gabriela Wyss
%J Praxishandbuch Bio-Lebensmittel
%I Behr's Verlag, Hamburg
%X Ökologische Lebensmitteln sind verschiedensten Kontaminationsmöglichkeiten (durch Pestizide, GVO, Mykotoxine, Weichmacher, Holzschutzmittel u.a.m) in der Produktion, bei der Be- und Verarbeitung, oder bei der Verpackung und Lagerung ausgesetzt. Die Ökoproduktion findet nicht auf einer Insel unter einer Glasglocke statt. Mit der immer stärker optimierten Analytikmethoden von Pflanzenschutz-, Schädlingsbekämpfungsmitteln und anderen Verbindungen können auch immer mehr Substanzen in geringen Konzentrationen gemessen werden. Die Vermeidung bzw. Verminderung des Eintrages von Schadstoffen in das System der Erzeugung von ökologischen Produkten ist ein wesentliches Element zur Schonung der natürlichen Ressourcen im Sinne einer nachhaltigen Landwirtschaft. Bei Verdacht hinsichtlich betrügerischer Aktivitäten entlang der Warenflusskette sind die Unternehmen gemäss EU-Öko-VO verpflichtet geeignete Abklärungen einzuleiten und den Sachverhalt zu klären. Dieses Kapitel möchte deshalb aufzeigen, wie durch den Beizug einer geeigneten Risikoabklärung aufgezeigt werden kann, wo in den Unternehmen mögliche Schnittstellen für erhöhte Risiken von Einträgen durch Kontaminationen bestehen und wie mit entsprechenden Massnahmen Einträge vermindert oder verhindert werden können. Im Leitfaden zum Vorgehen bei Verdacht auf Betrug wird aufgezeigt, durch welche Vorgehensweise (Sperren der Ware, Information der Lieferanten/Stellungnahmen einholen, Interne Prüfpunkte abklären, Entscheid Geschäftsleitung) das Unternehmen in möglichst kurzer Zeit Einsicht in die Begebenheiten erlangen kann.
Das Fallbeispiel Biowein zeigt mittels wissenschaftlich erarbeiteter Daten, wo Einträge von Pestiziden im Feld und in der Weinverarbeitung vorkommen können und wie diese gezielt vermindert oder verhindert werden können.

%A Gabriela Wyss
%L orgprints5921
%T Assessing the risk from mycotoxins for the organic food chain: results from Organic HACCP-project and other research
%E M. Hovi
%E M.  Walkenhorst
%E S. Padel
%X Introduction:
Mycotoxins are toxic compounds produced by the secondary metabolism of toxic moulds in the Aspergillus, Penicillium and Fusarium genera occurring in food commodities and foodstuffs. The range and potency of mycotoxins make this group of naturally occurring toxins an ongoing animal health hazard and a constant risk for contamination of the food supply.

Mycotoxicoses are diseases caused by exposure to foods or feeds contaminated with mycotoxins. Mycotoxins exhibit a variety of biological effects in animals, such as liver and kidney toxicity, central nervous system effects or estrogenic effects. There are differences between animals with regard to the susceptibility towards different mycotoxins. Poultry secrete mycotoxins relatively fast because of a particular digesting system. Ingredients used for animal feeding should be checked to ensure that adequate quality standards are maintained and that mycotoxins are not present at higher than acceptable levels. Good animal feeding practices also requires that feed is stored in such a way as to avoid contamination. As organically raised livestock are fed greater proportions of hay, grass and silage, there is reduced opportunity for mycotoxin contaminated feed to lead to mycotoxin contaminated milk.

Mycotoxins have been reported in organic produce. One theory is that organically-grown products are likely to contain higher concentrations of mycotoxins than conventionally grown products. However, there is little evidence to support this theory (Tamm et al. 2002). Higher or lower mycotoxin contents in feed and food made in different production systems may be caused by i) systematic differences in the production systems during pre-harvest (e.g. use of agrochemicals), ii) differences in post-harvest handling (e.g. storage, transport) and iii) differences during the transformation of raw products into processed foods. Also differences that are in fact due to improper handling procedures during harvest or post-harvest tend to occur systematically if there are systematic differences in the type of equipment used or in the technical qualifications of those who handle the products. Obvious omissions, regarding quality assurance, lead to poor quality but this phenomenon is not linked to organic agriculture in particular (Tamm 2001).

Within the 5th EU-framework project “Recommendations for improved procedures for securing consumer oriented food safety and quality of certified organic foods from plough to plate“(QLRT-2002-02245; “Organic HACCP”), a systematic analysis was carried out among selected certified organic food production chains, e.g. milk but also wheat bread. The aim was to investigate current procedures of production management and quality assurance related to the examined chains. For the quality and safety criteria “microbial toxins” (there were six more) the information was analysed to identify Critical Control Points (CCPs) and to suggest ways how the control of quality and safety can be further improved. CCPs were defined as the steps in supply chains where the qualities of the final product can be controlled most efficiently.
%J Systems development: quality and safety
%N ISBN: 07049 9851 3
%P 133-136
%K Mycotoxins, contamination, Organic HACCP, Qualitätssicherung
%D 2005

%D 2006
%K Lebensmittelqualität, Qualitätssicherung, Contamination, biologischer Landbau
%P 28-30
%J Tagungsband Forum Arbo Bio Romandie 2006
%I Forschungsinstitut für biologischen Landbau (FiBL), CH-Frick
%X La production, la transformation et la commercialisation de denrées alimentaires issues de l'agriculture biologique représentent un domaine très sensible. C'est avec droit que les consommatrices et les consommateurs posent des exigences élevées de qualité des denrées alimentaires produites biologiquement. Pour répondre à ces exigences, les entreprises agricoles doivent fournir d'importants efforts très divers. Ils prennent ces exigences au sérieux et en ont fait leur philosophie de qualité.
%L orgprints14785
%T Résidus de pesticides dans les fruits: situation en PI et bio cas problématiques et mesures
%A Gabriela S. Wyss

%X Problemstellung
Bioproduzenten und -produzentinnen wollen erstklassige Nahrungsmittel herstellen.
Dazu gehört auch der Verzicht auf chemisch-synthetische Pestizide, die häufig Rückstände in den Nahrungsmitteln verursachen.
Die zur Bekämpfung von Insekten oder Krankheiten zugelassenen Hilfsmittel sind in der Bio-Verordnung (SR 910.18) definiert und in der Hilfsstoffliste 2007 (1), welche für Produzenten der Labelorganisation Bio Suisse verbindlich ist, aufgelistet.
Auf der anderen Seite gelten die in der Fremd- und Inhaltsstoffverordnung (FIV; SR 817.021.23) angegebenen Höchstwerte grundsätzlich für alle Lebensmittel, unabhängig von ihrer Produktionsart. Aufgrund der Tatsache, dass die Anwendung chemisch-synthetischer Pestizide im Bio-Landbau nicht zulässig ist, stellen Konsumenten und Konsumentinnen allerdings an ein Bioprodukt höhere Ansprüche als an ein nicht-biologisch hergestelltes. Rückstände chemisch-synthetischer Pflanzenschutzmittel werden in biologisch produzierten Lebensmitteln nicht erwartet.
Erzeugnisse aus biologischem Anbau enthalten in aller Regel auch keine Rückstände.
%J Mitteilungen aus Lebensmitteluntersuchung und Hygiene
%N 97
%L orgprints13418
%T Konzept zur Beurteilung von Pestizidrückständen in Bioprodukten
%A Gabriela S. Wyss
%A Karin Nowack Heimgartner
%P 312-322
%K Lebensmittelqualität, Qualitätssicherung, Contamination, Pestizidrückstände, Pflanzenschutzmittel
%D 2006