Fatty acids in the diet For the comparison of organic and conventional animal-derived foods, the fatty acid composition of fresh milk and dairy products is the best studied quality parameter. The fatty acid composition is a nutritionally important parameter of dietary fats. Fatty acids are often grouped into saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. Each of these groups comprises a large number of individual fatty acids. PUFAs include omega-3 and omega-6 fatty acids.
The fatty acid composition is of relevance for various states of disease. As the probably most well-studied example, many Western diets have a relatively high share of SFA of total fat. Replacing SFA-rich foods by PUFA-rich foods has been shown to decrease the risk of cardiovascular diseases34, 35. The dietary fatty acid composition may also be of importance for other diseases, e.g. metabolic syndrome/ type II diabetes, and development of the immune system, but a review of this matter is beyond the scope of this report. It should be noted that not all aspects of how the fatty acid composition of the diet affects human health are well understood. Also, fatty acids in the diet always come as mixtures.
Two fatty acids, linoleic acid (C18:2 omega-6, LA) and α-linolenic acid (C18:3 omega-3, ALA), are essential to humans, as all other omega-3 and omega-6 fatty acids can be formed by the human body from these two, while all SFAs as well as other unsaturated fatty acids can be formed from acetate by humans. LA and ALA are also the most abundant omega-6 and omega-3 fatty acids in the diet, respectively. The optimum intake is generally a matter of balance.
With relevance for this chapter, omega-3 fatty acids, especially the long-chain docosahexaenoic acid (DHA, C22:6 omega-3), play important roles in the body. DHA has for example an important role in brain development, and is an abundant constituent of the brain and of neurons. As LA and ALA compete for the same enzymes in forming longer and more highly unsaturated fatty acids, it is sometimes claimed that the LA:ALA ratio in the diet should not be too high. Sometimes, an optimal ratio of 2.3 is proposed, while the average diet in Sweden has a omega-6/omega-3 ratio of ca 3.4 (calculated from median intakes of omega-6 and omega-3 fatty acid intakes presented in36). In Sweden, there are no specific recommendations for the intake of longchain omega-3 fatty acids (such as DHA), except for pregnant and lactating women (200 mg/day).
Importance of the feed for the fatty acid composition
Organic livestock husbandry requires that a large fraction of the feed should be locally produced. While soy, palm kernel cake, cereals, and maize silage are substantial feed fractions in many conventional livestock systems, they are less used ingredients in organic systems. On the other hand, grass-clover hay and other roughage make up a larger portion of the feed in organic than in conventional systems. There is a well-established link between the fatty acid composition of the feed, and the fatty acid composition in the product (milk, eggs, meat)37. Notably, soy, palm kernel cake, cereals and maize have a low content of omega-3, while grass and red clover are rich sources of omega-3 fatty acids
Milk and dairy products The composition of the feed determines to a large extent the fatty acid composition of the milk38. It is well established from studies in several countries and with a variety of study designs that the fatty acid composition is different in conventional compared to organic milk39. Organic milk consistently contains more omega-3 fatty acids than conventional milk, and the omega-6/omega-3 ratio is lower in organic milk. Also, many other fatty acids differ in their concentration between organic and conventional dairy products
Over 400 different fatty acids have been detected in milk fat, but only about 15 occur in concentrations above one percent. Furthermore, in most studies only the major fatty acids are analysed. The focus here is on some major and potentially important differences between organic and conventional milk related to the occurrence of omega-3, ruminant and long-chain polyunsaturated fatty acids.
Palupi and co-workers have summarized 13 individual studies from Europe and the USA39 and found that, on average, there is a 64 percent higher content of omega-3 fatty acids in organic milk than in conventional milk. The ratio of omega-6/ omega-3 fatty acids was 2.4 for organic and 4.3 for conventional milk. These numbers speak in favour of organic milk and dairy products.
For Sweden, it is sometimes stated in the public debate that the differences are less pronounced: Swedish cows, in contrast to cows in many other countries, have by law access to pasture during at least 2–4 months per year, depending on geographical latitude. The existing data only partly support such statements. For the outdoor season, two studies report the concentration of ALA, the most abundant omega-3 fatty acid in milk, and find 43 percent (central Sweden,40) and 67 percent (the region Scania in Southern Sweden,41) higher ALA in organic milk fat. For the indoor season, organic milk from south-eastern Sweden had 38 percent higher content of total omega-3 fatty acids compared to conventional milk42, while organic milk from Scania (southern Sweden) had 87 percent higher ALA compared to conventional milk. Accordingly, differences in omega-3 content between organic and conventional milk in Scania appear to be in line with differences reported from other countries, while such differences are somewhat less pronounced, but still present, in milk from southeastern and central Sweden.
A similar observation can be made regarding the omega-6/omega-3 ratio, where milk from Scania follows the international trend with a substantially higher ratio in conventional milk, while conventional indoor season milk from southeastern Sweden has a markedly low omega-6/omega-3 ratio but still higher than the organic milk. One explanation for these apparent regional differences is the fact that maize silage is a common feed component on conventional dairy farms in Scania, and in many other countries. In Sweden, maize is predominantly grown in Scania, and most of the crop is used for maize silage.
The season plays an important role in the fatty acid composition of milk. In both organic and conventional husbandry, the fraction of roughage is higher in summer than in winter, leading to a lower omega-6/omega-3 ratio in summer. The difference between the production systems is consistent in both summer and winter.
It is also established that organic milk has a higher content of conjugated linoleic acid (C18:2 cis-9 trans-11, CLA) and vaccenic acid (C18:1 trans-11, VA), compared to conventional milk. These fatty acids are collectively named ruminant fatty acids (see table 2 and 39). According to the Nordic Nutrition Recommendations, the intake of trans-fatty acids should be as low as possible. However, negative effects are most often attributed to industrial trans-fatty acids, while there is some evidence that ruminant trans-fatty acids have a favourable effect on human health. At this point this is not conclusive43. Furthermore, the long-chain omega-3 transfatty acids EPA and DPA are consistently found in higher concentrations in organic milk
Much less research has been done comparing the fatty acid composition of meat, and available studies are generally of highly varying design, and several of the studies are small. Also, meat is more difficult to sample at the farm level than milk. Apparently, as in the case of milk, the availability of clover-grass roughage, both as harvested feed and by grazing, leads to a higher omega-3 content of e.g. organic grass-fed beef45. By regulation and in practice, in Europe, organic cattle (and other animals) spend more time grazing than conventional cattle.
For example, in one study, sows grazed ca 2–2.5 kg clover and grass per day, corresponding to ca 50 percent of their energy intake46. Depending on the specific rules of certification, organic sows have access to pasture or grass-clover silage, while sows in conventional production are generally fed cerealbased concentrate feed.
In direct parallel to milk, and bearing in mind the known37 importance of the feed fatty acid composition for the meat fatty acid composition, organic meat has the potential of having a more preferable fatty acid composition than conventional meat, e.g. higher omega-3 content and a lower omega-6/ omega-3 ratio. Indeed, several studies on beef47, pork48, lamb49, chicken50, 51, rabbit52 have shown such trends, although some exception exist.
To date, however, no formal meta-analysis of these and other studies has been performed, and the high variability in study designs and feeding regimes in the studies comparing organic and conventional meat composition hampers definite conclusions. However, it is likely that findings on the difference between organic and conventional milk composition are paralleled by similar differences in meat, because a high intake of fresh forage and roughage, with a known beneficial effect on meat fatty acid composition, is guaranteed in most organic systems.
Few studies on the fatty acid composition of organic and conventional eggs have been published. One study reports higher omega-3 fatty acid content and a lower omega-6/omega-3 ratio in organic eggs, especially when pasture was widely available55. Hens were kept indoors in a standard housing system (“control”), with access to 4 m2 of pasture per hen (“organic”), in line with current requirements for organic laying hens, or with access to 10 m2 of pasture (“organic plus”).
For example, the annual average of DHA was 88 mg/100g egg yolk for control chicken, 110 mg/100g for organic chicken, and 321 mg/100g for “organic plus” chicken. This underlines the importance of hens having access to grass pasture for egg fatty acid quality. In the EU, laying hens and broilers in organic production have access to at least 4 m2 of pasture per animal by regulation, while conventional laying hens typically do not have access to pasture.
Other qualities The fatty acid composition is of course not the only quality trait of milk, dairy products, meat, and eggs. The focus is here put on the fatty acid composition because they constitute an important and well-researched group of nutrients. There are indications that other beneficial feed components can end up in the food, and can therefore be modulated by the agricultural system. For example, a high access to pasture for laying hens appears to cause a high content of flavonoids in eggs.
Significance for health Little research on health effects of a differential dietary fatty acid composition as a consequence of organic vs. conventional food preferences has been performed. In the Dutch KOALA cohort study mentioned earlier (page 9), it has been shown that the breast milk of lactating women with a strong preference for organic meat and dairy products had a similar omega-3 fatty content but a 36 percent higher CLA and a 23 percent higher vaccenic acid (VA) content, compared to women preferring conventional food56. In the KOALA study, it has also been shown that a high content of ruminant fatty acids (CLA + VA) and long-chain omega-3 fatty acids (EPA + DPA + DHA) were associated with lower incidences of parent-reported eczema until two years of age, atopic dermatitis at two years of age, and allergic sensitisation in the children at one year of age but not at 2 years57. This suggests a mild allergy-protective effect of some fatty acids that are present in higher concentrations in organic animalderived products than in conventional products.
There is a lively ongoing scientific debate on the importance and effect of various dietary fatty acids on human health. Nonetheless, from a fatty acid perspective, most nutritionists would probably prefer organic milk over conventional milk due to the higher content of very-long-chain PUFA in organic milk, due to the higher content of long-chain omega-3 fatty acids, or due the lower omega-6/omega-3 ratio in organic milk.
It should be kept in mind that animal-derived foods are not the only source of fat for humans. The choice of what plant oil to use in cooking, or if butter or plant-based margarine are used as bread spreads, will generally outweigh the choice of conventional or organic animal products for the overall fatty acid composition of a diet. On the other hand, fat from animal sources (excluding fish) accounts for approximately 40 percent of the total fat intake in the Swedish adult population36. Accordingly, changes in the fatty acid composition in our food from animal origin will have an effect on our overall fatty acid intake.
Significance for adherence to dietary guidelines According to a Swedish dietary survey36, approximately 40–45 percent of the adult population has a dietary intake of total omega-3 fatty acids (ALA, EPA, DHA, DPA) below the recommended one energy-percent (E-%) (see table 1); the median intake of DHA is 0.4 g/day
For children, the median omega-3 fatty acid intake was 0.6 E-% for children aged 4, 8 and 11 years, with a median DHA intake of 60, 80 and 70 mg/ day for these age groups58. Over 90 percent of the children had a lower than recommended intake of omega-3 fatty acids.
There are several dietary changes available to achieve the recommended omega-3 fatty acid intake, namely an increased consumption of fatty fish or certain plant oils. However, for young children, some dietary changes (e.g. fatty fish) may not be viable, because 4-year old children do not generally respond well to dietary advice. In such cases, increasing the omega-3 density of the diet by choosing organic food could be an important contribution to a healthy diet.
The intake of PUFA from milk and dairy products (including butter and cheese) amounts to about eight percent of the total PUFA intake in the Swedish adult population. The intake of PUFA from eggs and meat make up another 19 percent of total PUFA intake. This amounts to five percent (from milk) and twelve percent (eggs and meat) of omega-3 intake.
To our knowledge, no one has so far calculated how many people would meet the recommended intake of omega-3 fatty acids if all intake was from conventional vs. organic production, although data from extensive surveys such as Riksmaten36 would relatively easily allow for such estimates. Assuming an approximately 50 percent higher omega-3 fatty acid content in organic milk fat and a five percent contribution by milk fat to the total omega-3 fatty acid intake of the Swedish population, a rough estimate is that on average an individual would increase the omega-3 fatty acid intake by 2.5 percent by switching from conventional to organic milk and dairy products. This is a small but conclusive difference (in contrast to e.g. differences in vitamin C intake due to organic and conventional fruit and vegetables). Should future work confirm that even organic eggs and meat have a similar advantage over their conventional counterparts with respect to omega-3 content, then this difference may be relevant for meeting the recommendation for omega-3 fatty acid intake for a substantial part of the population, most notably children. For 4-year-old children, dairy products (including butter) account for about six percent of the PUFA intake, and meat and eggs for 21 percent58, 60, similar to adults. In summary, a higher omega-3 content in organic dairy products leads to a higher intake for a consumer who prefers organic over conventional dairy products. The increase is small (about 2.5 percent on average) but definitive and desirable, because a substantial fraction of the population does not reach the recommended omega-3 intake. The increase may also be larger and more important for population groups with a high intake of animalderived fats.
Basics of regulation in the EU In the European Union and other countries, extensive risk assessment is performed before pesticides for agricultural use are approved. The process of approval is very complex, and only a rough overview with a focus on the EU is given here. Companies that seek approval for a new pesticide compound (“active substance”) have to perform a substantial amount of studies, investigating potential adverse effects for humans (using in vitro and animal studies) and the environment. Based on these data, one national regulatory authority carries out a risk assessment on behalf of the European Food Safety Authority (EFSA). This risk assessment is then reviewed by the other EU member states’ national authorities. Finally, EFSA issues a “Conclusion on the peer review of the pesticide risk assessment”, on which the European Commission bases its decision of approval or non-approval (“Review report”).
This process is regulated in EU regulation 1107/200961. The stated purpose of this regulation is ”… to ensure a high level of protection of both human and animal health and the environment and to improve the functioning of the internal market through the harmonisation of the rules on the placing on the market of plant protection products, while improving agricultural production.
Safe levels of exposure It is the company seeking approval that has to provide the EU with data of the toxicology and ecotoxicology of the active substance. For example, companies have to present studies regarding acute toxicity, genotoxicity, carcinogenicity, reproductive toxicology, delayed neurotoxicity in mammals (often rats) and/or in cell assays, data on the behaviour and degradation of the active substance in the environment. Effects on bees, earthworms, and fish
have to be assessed, along with many other aspects of toxicology and environmental fate. The current data requirements are detailed in EU regulation 283/201362. Commonly, safe levels of exposure (no observed adverse effect level – NOAEL) measured in animal studies are translated into safe levels for humans by the application of a safety factor (often a factor of 100) to account for variation in susceptibility between species and between individuals. The active substance will be approved when it is established by the risk assessment that its use does not cause harm to human or animal health or to groundwater, and it does not pose unacceptable risks for the environment.
Furthermore, the substance should be effective for its purpose, and not cause unnecessary suffering on vertebrates to be controlled, and not cause unacceptable effects on plants. An active substance may have toxic properties but will still be approved if its proper use does not lead to an exposure (via exposure at work or via residues in food) that poses a risk. An exception are the cut-off criteria for mutagenic, carcinogenic, and endocrine disrupting properties and reproductive toxicity, detailed in Annex II of EU regulation 1107/200961. Active substances which with high confidence have such properties cannot be approved (with some exceptions). This extensive risk assessment is justified by the facts that pesticides comprise the only group of commercially available chemicals that are designed to kill organisms, and that they are sprayed outdoors implying a risk of spreading into the environment. There are also risks for effects on nontarget organisms in the agricultural landscape.
One result of the pesticide risk assessment is the establishment of an Acceptable Daily Intake (ADI, an amount of pesticide which may be ingested every day without estimated risks to human health) and an Acute Reference Dose (ARfD, an amount of pesticide which should not be exceeded at a single occasion).
In case of approval of the active substance by the EU Commission, the actual pesticide product (containing the active substance and other ingredients) has then to be assessed according to specific harmonized criteria in each EU member state where the company wants to market its product before it can be authorized for use. Approvals are normally valid for 10 years.
Gaps in risk assessment One inherent weakness of this kind of risk assessment is that only those risks can be found that manifest themselves in the standardized tests, which are often years behind the development of science. For example, although some endocrine disrupting effects of pesticides have been discovered several decades ago (e.g. in the case of DDT), the cut-off criterion for endocrine disruption is still today (January 2015) not operational, because so far no scientific criteria and no technical guidelines are specified by the EU, that describe suitable tests for endocrine disruption. Some adverse endocrine effects could be discovered in certain studies, e.g. when studying the litter size of exposed and unexposed rats. But many more subtle effects of pesticides on the hormone system, which along with the neural system form the body’s “communication system”, may go undetected by today’s risk assessment. The EU commission should have presented scientific criteria for the determination of endocrine disrupting properties by December 2013, but has not yet done so. The Swedish government has recently announced that it will take legal action against the European Commission on a similar issue: the same criteria for endocrine disruption are also missing for biocides, which is a group of pesticides for other than agricultural use, falling under different legislation.
Criteria for endocrine disruption are now expected to be specified in 2015 or 2016. Depending on the actual form of the final criteria (i.e. if such criteria can be tested using existing test guidelines), these may or may not be directly implemented. In any case, accepted test methods exist for effects mediated by the estrogen and androgen receptors, thyroid hormones, and for interference with steroidogenesis (i.e. the formation of steroids from cholesterol), but not for the other about 50 hormone systems in the human body63. For example, potential effects of pesticides on the corticosteroid system, with relevance for the development of diabetes, are unlikely to be detected in the risk assessment even when the endocrine effects are finally part of the assessment. It will take years or decades to develop tests for all human hormone systems.
The hormone system is sensitive One reason why the EU commission has established a cut-off criterion for endocrine effects is the fact that dose-response relationships for hormones may be non-monotonous. For most other toxic effects, typically higher doses result in stronger effects, and in consequence, if one specific dose is shown to be safe, then all lower doses are also safe. For hormones, this is not necessarily true: in some cases, lower doses may produce effects that cannot be predicted from effects at higher doses, and dose-response curves may have all kinds of peculiar shapes64. In some cases of critical windows of exposure, the timing of exposure, rather than the dose, may be critical. Furthermore, in in vitro* studies, cases have been observed where the concentration of an endocrine disrupting compound was more than 100 times lower in human than in mouse and rat testis cells; in some other cases, endocrine effects found in mouse or rat cells were entirely absent in human testis cells. These inter-species variations are larger than in typical toxicological models, and raise concern about the use of animal models for estimating endocrine effects on humans.
As an illustrative example, one research group screened in vitro 37 pesticides that are commonly found as residues in food for their anti-androgenic potential, i.e. their potential to interfere with certain sex hormones66. Of those compounds 14 have previously been known to show anti-androgenic behaviour, which was confirmed in this study. Of nine further compounds, such an effect was demonstrated where previously unknown. Further seven compounds showed an androgenic effect (i.e. an “opposite” effect). It should be noted that this work addressed only one of approximately 50 hormone systems in humans. Human fertility may be affected The example illustrates that a number of the widely used pesticides may exhibit an effect on the endocrine system. This is possible because effects on the hormone system are not part of the process of approval of pesticides in the EU, as mentioned earlier. It is impossible today to judge whether the population’s exposure to such pesticides via food represents an actual health risk or not, for example, the extent to which pesticides are responsible for observed declines in human fertility. Also, even for tests accepted by the OECD (Organisation for Economic Co-operation and Development), there is not always agreement among scientists that such tests accurately identify risks. For example, in an evaluation of a guideline for developmental neurotoxicity67 (i.e. effects of chemicals on the development of the offspring’s neural system during pregnancy or childhood), 16 studies of five evaluated chemicals have been summarized68. Of these, five studies were performed according to the OECD guideline TG 426, all but one found no sign of developmental neurotoxicity. In contrast, of the eleven studies not performed according to the guideline, all found evidence of developmental neurotoxicity. A more recent and extensive survey of studies investigating the potential developmental neurotoxicity of the compound Bisphenol A (BPA) suggests that studies performed according to guideline TG 426 may overlook sensitive effects of BPA, especially in female offspring. Especially anxiety-related, social and sexual behaviours, which are not tested according to TG 426, were found to be affected by BPA exposure during development69. One example of potential developmental neurotoxicity (chlorpyrifos) is discussed in some detail below, in section “In-depth example: Developmental neurotoxic effects of chlorpyrifos.
Another weakness is that (with few exceptions for chemically closely related compounds) the current risk assessment considers only one pesticide at a time, in spite of the obvious fact that we all are constantly exposed to a large number of pesticides simultaneously via our food. The reasons are methodological difficulties in estimating the effects of exposure to multiple compounds, and companies have the right to have their product assessed on its own merits, i.e. independent of which products their competitors sell.
Effects of several pesticides may add up to adverse effects. In animal studies, cases are known where mixtures of pesticide cause adverse effects at dose levels where the individual pesticides show no effect 70, 71 (so-called cumulative effects).
Independent science is disregarded One weak point of the regulatory process of pesticide approval is the fact that independent science has a low impact on this process. Since Regulation
1107/200961 came into effect, independent science must be considered in the process of pesticide approval. However, an EFSA guidance document72 effectively assigns independent studies a low impact, and in consequence, independent science is generally disregarded73. For example, of the hundreds of epidemiological studies of pesticide effects exposure on human health (discussed in chapter “Public health effects of low-level pesticide exposure” below), to our knowledge not a single one has been considered valid when setting toxicological reference values in EFSAs risk assessment in the approval process of pesticides.
Of course, epidemiological studies are not generally designed for the purpose of regulatory risk assessment. For example, epidemiological studies generally cover “real-life” situations with a coexposure to various pesticides and other chemicals, and may assess exposure to single compounds, groups of pesticides, or overall pesticide exposure. In contrast, in regulatory risk assessment, all animal studies are performed using the individual compound, without consideration of mixed exposures. Nonetheless, the fact that no epidemiological study is regarded relevant for the regulatory risk assessment might indicate that systematic barriers exist against the inclusion of such studies, and puts focus on the question whether current regulatory risk assessment indeed uses all available knowledge. It should be mentioned that the approval process is intended not only to protect the environment and consumers from negative pesticide effects, but also farm workers. In many epidemiological studies, effects on farm workers are addressed. One example of what this can mean in practice is discussed in detail below, in section “In-depth example: Developmental neurotoxic effects of chlorpyrifos”.
Another issue is that the studies submitted by the industry to EFSA are generally “protected” (not available for the public or for researchers).
Also, for some of the chronic diseases that have increased during recent decades in many countries, the mechanisms of disease onset are still unknown. This applies for example to allergies, Alzheimer’s disease, type 2 diabetes, obesity, decreasing fertility, ADHD. Many of these diseases have been linked to exposure to endocrine disrupting compounds in animal and human studies74. Lacking knowledge of the biochemical and physiological mechanisms, it is in some cases difficult or impossible to develop adequate tests that demonstrate the safety of active substances.
Furthermore, all toxicological risk assessment is based on extrapolations (with safety margins) from animal studies, and there is normally no direct knowledge of effects in humans. Direct toxicological tests in humans would be unethical. However, the structured collection of reported adverse effects after market release (e.g. from farmers) and the conducting of epidemiological studies (in farmers and consumers) are examples of viable approaches to measuring some potential “real-life” adverse effects in humans. Today, no such effort of validating the findings of the risk assessment after market release is done or required by the regulatory authorities.
There is substantially more focus on the active substance than on its metabolites in the safety assessment of pesticides. For example, the approval of the fungicide carbendazim has expired in the EU (in november 2014) without a chance of re-approval, because carbendazim is now classified in mutagenicity category 1B (“Substances to be regarded as if they induce heritable mutations in the germ cells of humans”), and therefore the cut-off criterion for mutagenicity (see section “Basics of regulation in the EU” above) applies.
The fungicide thiophanate-methyl forms carbendazim as a metabolite both in the field and after ingestion by mammals. The cut-off criterion for mutagenicity does, however, not directly apply for thiophanate-methyl, as it only applies for active substances, safeners, and synergists, but not for metabolites.
Another issue is that the EU member states have the possibility of temporarily authorizing the marketing of banned pesticides. This possibility was originally intended as an emergency response (to tackle dangers (e.g. outbreaks of plant diseases and insects) that could not be dealt with by other reasonable means), but has been used frequently. For example, in 2011, 230 such “derogations” were issued by the EU member states.
Pesticides in organic agriculture Pesticides approved for organic agriculture in the EU are specified in Annex II of Regulation 889/200876, and the most recent update of this list can be found in Regulation 354/201477. As a general principle, synthetic substances are not approved but natural substances (e.g. extracts from plants or microorganisms) can be approved. Pesticides approved in organic farming are evaluated according to the same EU regulations as described above for other pesticides.
In many cases, pesticides that are allowed in organic production are less effective than synthetic alternatives, potentially meaning that a higher number of “organic” pesticide applications are necessary in order to achieve the same effect as a “conventional” pesticide. However, fuelled by the non-availability of effective pesticides, organic agriculture has developed and is further developing preventive approaches to pest and weed control, such as crop rotations, mechanical weed control, the use of disease-resistant varieties, supporting natural enemies to pests, push-pull management, and others.
In Sweden, currently nine active substances are approved in organic agriculture (i.e. they are specified in Annex II of Regulation 889/200876 and at least one product containing that substances is approved for use in Sweden by the Swedish Chemicals Agency). Three of these may only be used in insect traps. The remaining six substances are pyrethrins, spinosad, rapeseed oil, iron (III), sulphur, and paraffin oil. Of these, only pyrethrins and spinosad are of toxicological relevance; EFSA has not assigned ADI or ARfD values to rapeseed oil, sulphur, and paraffin oil due to low toxicity. Iron is an essential metal to humans but has a long-term toxicity at higher amounts.
Furthermore, pheromones and pyrethroids (only deltamethrin or lambda-cyhalothrin) may be used in insect traps, with very little risk of spreading into the environment.
Probably the substance of highest concern among pesticides approved for organic agriculture in the EU is the pyrethrins, a mixture of insecticidal substances naturally occurring in the flower Chrysanthemum cinerariifolium. The pyrethrins share the same mechanism of neurotoxicity as their synthetic analogues, the pyrethroids. Generally, the synthetic pyrethroids are designed to be more stable than their naturally occurring analogues, meaning that fewer applications are necessary. On the other hand, a higher stability implies a higher risk for residues being present on the product in the shop, and the limited effectiveness of pyrethrins might limit their use. Pyrethrins are only rarely found as residues on food. For a risk assessment of actual spinosad and pyrethrins exposure, see section “Residues of pesticides approved for organic agriculture” below.
The substance rotenone, another substance of concern due to its neurotoxic effects, has earlier been approved in organic agriculture as an extract of certain plants. Rotenone has recently been removed from the list of pesticides approved for organic agriculture in the EU