The Extra-Virgin Olive Oil Handbook (Peri/The Extra-Virgin Olive Oil Handbook) || Extra-virgin olive oil contaminants

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<ul><li><p>7Extra-virgin olive oilcontaminantsCristina AlampreseDepartment of Food, Environmental and Nutritional Sciences,University of Milan, Milan, Italy</p><p>Abstract</p><p>This chapter gives some basic information about extra-virgin olive oil contaminantsand the associated risks. The list includes: mycotoxins, micro-organisms, pesticideresidues, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons(PAHs), organic solvents, phthalates, lubricants, and particulate materials. Maxi-mum levels set for contaminants by Codex Alimentarius, IOC and EU regulationsare reported. Conditions that determine or favour contamination and precautionsfor preventing them are discussed. In general, the health risk associated with theconsumption of olive oils is low.</p><p>7.1 Introduction</p><p>Contaminants include micro-organisms, chemicals or particulate material thatshould not be present in extra-virgin olive oil at concentrations that could beharmful to human health.</p><p>Biological hazards derive from pathogenic and toxinogenic bacteria, fungi andviruses. They may grow and multiply in the olives before processing. Also, thepresence of excess water and organic material may provide suitable conditions formicrobial growth in unfiltered oil, giving rise to sensory defects.</p><p>Chemical hazards are the most serious hazards in extra-virgin olive oil. Toxicchemical contaminants may derive from:</p><p> pesticide residues due to substances used in the treatment of olive trees or tocombat pests and rodents in olive oil factories and stores;</p><p>The Extra-Virgin Olive Oil Handbook, First Edition. Edited by Claudio Peri. 2014 John Wiley &amp; Sons, Ltd. Published 2014 by John Wiley &amp; Sons, Ltd.</p></li><li><p>76 CH07 EXTRA-VIRGIN OLIVE OIL CONTAMINANTS</p><p> local contamination of groundwater or air or soil, and industrial wastes;</p><p> smoke components from the environment surrounding the olive oil factory.They may contain soluble lipophilic constituents and fine particles that cancontaminate the oil during processing, handling and storage;</p><p> lipophilic volatiles (solvents) arising from industrial pollution in the area ofolive cultivation or oil production and storage;</p><p> plastic bottles, bags, containers, piping or conveyors containing, for instance,phthalates, used as plasticizers of polymeric materials (especially PVC), toxicmonomers and oligomers.</p><p>Physical hazards include a variety of foreign bodies that can derive from:</p><p> olive harvesting and handling (stones, metal, insects, undesirable plant mate-rial, soil, etc.);</p><p> oil processing and handling operations (glass, metal, wood, bolts, screeningand wire, cloth, grease, paint chips, insects, soil, and so on).</p><p>Various potential contaminants of extra-virgin olive oil are listed in Table 7.1along with a qualitative evaluation of the likelihood of risk.</p><p>In general, the health risk associated with the consumption of extra-virgin oliveoil is low. This reassuring observation is reinforced by two circumstances:</p><p> The risks associated with degradation of the olives or the oil determine down-grading of the oil to the lampante level. Contaminants are therefore removedin the refining process;</p><p> Only lipid-soluble contaminants represent a risk because of their affinity andsolubility in oil. The water-soluble contaminants, which may be present in theolive or may come into contact with the oil during the olive milling process,are eliminated with the wastewater or the pomace.</p><p>For all the other hygienic hazards, suitable conditions for safety are guaranteed by:</p><p> location of the oil factory in a low polluted site;</p><p> good hygienic control of the process and the environment (see Chapter 21);</p><p> filtration of the oil;</p><p> oil storage in hermetically sealed containers.</p></li><li><p>7.1 INTRODUCTION 77</p><p>Tabl</p><p>e7.</p><p>1Po</p><p>tent</p><p>ialc</p><p>onta</p><p>min</p><p>ants</p><p>ofex</p><p>tra-</p><p>virg</p><p>inol</p><p>ive</p><p>oil(</p><p>Mel</p><p>onie</p><p>tal.</p><p>2005</p><p>).</p><p>Type</p><p>ofco</p><p>ntam</p><p>inat</p><p>ion</p><p>Con</p><p>tam</p><p>inan</p><p>tM</p><p>ain</p><p>caus</p><p>esof</p><p>cont</p><p>amin</p><p>atio</p><p>nL</p><p>ikel</p><p>ihoo</p><p>dof</p><p>risk</p><p>(see</p><p>Cha</p><p>pter</p><p>21)</p><p>Inad</p><p>equa</p><p>teco</p><p>ntro</p><p>lof</p><p>the</p><p>agro</p><p>nom</p><p>ican</p><p>dol</p><p>ive</p><p>hand</p><p>ling</p><p>oper</p><p>atio</p><p>ns</p><p>Inad</p><p>equa</p><p>teco</p><p>ntro</p><p>lof</p><p>the</p><p>mil</p><p>ling</p><p>and</p><p>stor</p><p>age</p><p>oper</p><p>atio</p><p>ns</p><p>Inad</p><p>equa</p><p>teco</p><p>ntro</p><p>lof</p><p>envi</p><p>ronm</p><p>enta</p><p>lhyg</p><p>iene</p><p>insi</p><p>dean</p><p>dou</p><p>tsid</p><p>eth</p><p>efa</p><p>ctor</p><p>y</p><p>Bio</p><p>logi</p><p>cal</p><p>Myc</p><p>otox</p><p>ins</p><p>++</p><p>Ext</p><p>rem</p><p>ely</p><p>unlik</p><p>ely</p><p>Mic</p><p>robi</p><p>algr</p><p>owth</p><p>+E</p><p>xtre</p><p>mel</p><p>yun</p><p>likel</p><p>yC</p><p>hem</p><p>ical</p><p>Pest</p><p>icid</p><p>ere</p><p>sidu</p><p>es+</p><p>Unl</p><p>ikel</p><p>yFu</p><p>ngic</p><p>ide</p><p>resi</p><p>dues</p><p>+V</p><p>ery</p><p>unlik</p><p>ely</p><p>Her</p><p>bici</p><p>dere</p><p>sidu</p><p>es+</p><p>Ext</p><p>rem</p><p>ely</p><p>unlik</p><p>ely</p><p>Poly</p><p>cycl</p><p>icar</p><p>omat</p><p>ichy</p><p>droc</p><p>arbo</p><p>ns(P</p><p>AH</p><p>s)+</p><p>Ver</p><p>yun</p><p>likel</p><p>y</p><p>Poly</p><p>chlo</p><p>rina</p><p>ted</p><p>biph</p><p>enyl</p><p>s(P</p><p>CB</p><p>s),d</p><p>ioxi</p><p>ns+</p><p>Ver</p><p>yun</p><p>likel</p><p>y</p><p>Smok</p><p>eco</p><p>mpo</p><p>nent</p><p>s+</p><p>Unl</p><p>ikel</p><p>yO</p><p>rgan</p><p>icso</p><p>lven</p><p>ts+</p><p>Unl</p><p>ikel</p><p>yPh</p><p>thal</p><p>ates</p><p>+V</p><p>ery</p><p>unlik</p><p>ely</p><p>Lub</p><p>rica</p><p>nts</p><p>+U</p><p>nlik</p><p>ely</p><p>Det</p><p>erge</p><p>nts</p><p>+V</p><p>ery</p><p>unlik</p><p>ely</p><p>Phys</p><p>ical</p><p>Frag</p><p>men</p><p>tsan</p><p>dre</p><p>sidu</p><p>esfr</p><p>ompe</p><p>sts</p><p>+U</p><p>nlik</p><p>ely</p><p>Ston</p><p>es,m</p><p>etal</p><p>,pla</p><p>stic</p><p>,wir</p><p>e,cl</p><p>oth,</p><p>woo</p><p>d,so</p><p>il,et</p><p>c.+</p><p>Unl</p><p>ikel</p><p>y</p><p>Gla</p><p>ssfr</p><p>agm</p><p>ents</p><p>+U</p><p>nlik</p><p>ely</p></li><li><p>78 CH07 EXTRA-VIRGIN OLIVE OIL CONTAMINANTS</p><p>7.2 Contaminants of virgin olive oil</p><p>Legal limits for various olive oil contaminants are given in Table 7.2.</p><p>Table 7.2 Legal limits for some olive oil contaminants (Codex Stan 33-1981 19812013).</p><p>Contaminant Virginolive oils</p><p>Olive oil Refinedolive oil</p><p>Olive-pomaceoil</p><p>Moisture and volatile material (%) 0.2 0.1 0.1 0.1Insoluble impurities (%) 0.1 0.05 0.05 0.05Trace metals (mg/kg):</p><p>Iron (Fe) 3 3 3 3Copper (Cu) 0.1 0.1 0.1 0.1</p><p>Heavy metals (mg/kg):Lead (Pb) 0.1 0.1 0.1 0.1Arsenic (As) 0.1 0.1 0.1 0.1</p><p>Halogenated solvents, max. content:of each solvent (mg/kg) 0.1 0.1 0.1 0.1of the sum of all solvents (mg/kg) 0.2 0.2 0.2 0.2</p><p>7.2.1 Mycotoxins</p><p>Mycotoxins are water-soluble, relatively low-molecular weight, secondary metabo-lites of fungal origin that are harmful to animals and humans. The amount of myco-toxins needed to produce adverse health effects varies widely among toxins, as wellas for each animal or persons immune system. Mycotoxins can be acutely or chron-ically toxic, or both, depending on the kind of toxin and the dose. The EuropeanCommunity sets the tolerance level for some food products but edible oils are notspecifically addressed (Commission Regulation (EC) No 1881/2006).</p><p>If olives are stored for several weeks under conditions that contribute to the growthof moulds, mycotoxin contamination may occur. Ochratoxin A and aflatoxin B, bothmutagenic, have rarely been found in extra-virgin olive oil and, when found, theywere at extremely low concentrations with no toxic effect. In some cases, higherconcentrations have been found in lampante oils derived from unhealthy, rottenolives. In this case, however, mycotoxins are eliminated by the refining process forthe production of food-grade refined olive oil. In conclusion, it may be said that thepresence of mycotoxins in extra-virgin olive oil is extremely rare and therefore theoverall gravity of risk should be considered as negligible.</p><p>7.2.2 Micro-organisms</p><p>Microbial growth is very unlikely because extra-virgin olive oil does not containsugars and nitrogenous compounds that are essential nutrients for growth of micro-organisms.</p></li><li><p>7.2 CONTAMINANTS OF VIRGIN OLIVE OIL 79</p><p>Some bacterial growth and fermentation can take place only in the presence ofwater and organic material. This is quite common especially when oils are not fil-tered. It is more common to find yeasts and moulds than bacteria. In any case,microbial growth does not represent a health hazard, but can cause quality degra-dation with increase in free acidity, peroxide and spectrophotometric values andformation of sensory defects, such as fusty and muddy sediment (moulds) or wineyand vinegary (yeasts).</p><p>The presence of water is a necessary condition for bacterial growth and activity,so excess water should be carefully avoided. It is interesting to note that the CodexAlimentarius has set a limit of 0.2% water in extra-virgin olive oil (Codex Stan33-1981 19812013). This is one of the least checked and one of the most oftentransgressed standards of extra-virgin olive oil.</p><p>7.2.3 Pesticide, fungicide and herbicide residues</p><p>Pesticides are chemical substances that are used to control or prevent pest attack.In the case of olive oil, control treatments against the olive fly (Bactrocera oleae)are the most frequently applied and therefore their residues are the most frequentlyfound pesticide in the oil. Several pesticides are used, such as synthetic pyrethroids,organochlorine and organophosphorous insecticides. In regions where there is a lowrate of attack, a single pesticide treatment at the start of the second generation of thefly is sufficient. In areas with high attack rates (such as coastal areas and valleys)treatment for the second and third generation is normally required. In this case, acareful control of residues in the oil may be advisable. In any case, pesticide treat-ments must be carried out with authorized products and active ingredients and muststrictly conform to the required withholding periods in order to avoid residues inthe fruit at the time of harvest. Conformity to these prescriptions should be dulydocumented.</p><p>Fungicides based on copper products and copper mixes have a relatively lowtoxicity, thus they are to be considered as a negligible risk. The legal limit forcopper compounds in olives for oil production is set at 30 mg/kg by the EuropeanCommunity (Commission Regulation (EC) No 149/2008). Even the use of organicfungicides should be normally considered as safe in terms of oil contamination andresidues. The use of herbicides should be considered as safe, especially in the caseof harvesting from the tree (the only acceptable method in extra-virgin olive oilproduction) and not by picking up the olives from the soil.</p><p>A more subtle risk may derive from pest traps and pesticide treatments in olivemills and oil storage facilities. These practices, which are part of any good HygieneManagement System (Chapter 21), should be carried out by skilled operators undercarefully controlled conditions.</p><p>Due to an increasing awareness of the possible risks involved with the use of pesti-cides, strict regulations for maximum residue limits (MRLs) for these contaminantshave been fixed by the Codex Alimentarius (Table 7.3) and by the European Commu-nity (Codex Stan 33-1981 19812013; Commission Regulation (EC) No 149/2008).</p></li><li><p>80 CH07 EXTRA-VIRGIN OLIVE OIL CONTAMINANTS</p><p>Table 7.3 Maximum residue limits of pesticides in virgin olive oil(CAC/MRL 1 2009).</p><p>Pesticide MRL (mg/kg) GHS category</p><p>Cypermethrins (including alpha-and zeta- cypermethrin)</p><p>0.5 3</p><p>Kresoxim-methyl 0.7 3Fenthion 1 3Carbaryl 25 3</p><p>MRL: maximum residue limit; GHS: globally harmonized system ofclassification and labelling of chemicals (GHS 2003).</p><p>Table 7.4 A simplified summary of the Globally Harmonized System (GHS) of categoryclassification of toxic substances (GHS 2003).</p><p>Category 1 Category 2 Category 3 Category 4 Category 5</p><p>Exposure:Oral (LD50, mg/kgbodyweight)</p><p>5 50 300 2000 5000</p><p>Dermal(LD50, mg/kgbodyweight)</p><p>50 200 1000 2000 5000</p><p>Hazard statement:Oral Fatal if</p><p>swallowedFatal if</p><p>swallowedToxic if</p><p>swallowedHarmful if</p><p>swallowedMay be</p><p>harmful ifswallowed</p><p>Dermal Fatal incontactwith skin</p><p>Fatal incontactwith skin</p><p>Toxic incontactwith skin</p><p>Harmful incontactwith skin</p><p>May beharmful incontactwith skin</p><p>On the basis of the acute toxicity estimate value, chemicals are classified in fourcategories of the Globally Harmonized System of Classification and Labelling ofChemicals (UN 2003; Environmental Protection Agency 2012) (Table 7.4). Acutetoxicity refers to adverse effects occurring after oral or dermal administration of asingle dose of a substance, or multiple dose exposure within 24 hours. Most pesti-cides are generally included in Category 3.</p><p>Further considerations have to be made about pesticides and fungicides. Firstof all, in the Mediterranean area, there is a vast assortment of olive tree varieties.In these conditions a subtle balance between olive trees and their pathogens orother damaging agents has been established. Only when such balance is altereddo severe attacks and considerable losses occur. Unfortunately, significant changesand variability in the climate are altering these equilibriums, as well as the newintensive olive growing practices (irrigation, fertilization, high density). Indiscrimi-nate or excessive pesticide, fungicide and herbicide treatments contribute further to</p></li><li><p>7.2 CONTAMINANTS OF VIRGIN OLIVE OIL 81</p><p>destabilizing the ecosystem equilibriums by destroying useful insect communities,microbial colonies in the soil and wild plant species.</p><p>Finally, it must be emphasized that the use of pesticides, fungicides and herbi-cides may represent a serious risk to workers health in the handling of highly toxicsubstances.</p><p>Any guarantee or certification scheme of extra-virgin olive oil quality and safetymust include:</p><p> monitoring of pest and disease evolution in order to minimize the number oftreatments;</p><p> education, training and protection of workers for the most effective and carefuluse of toxic substances;</p><p> registration of treatments including date, products, quantities, concentrationand mode.</p><p>Use of traditional olive cultivars and sustainable agricultural practices, includingintegrated and organic agriculture, should be encouraged.</p><p>7.2.4 Environmental pollutants</p><p>Many environmental pollutants result from local contamination of groundwater orair or soil with industrial wastes. Among them the most feared are organochlo-rine compounds, known for their persistence and toxicity. Olive oils may containresidues of hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT) andpolychlorinated biphenyls (PCBs). Small amounts of PCBs may be formed duringcombustion of materials containing carbon and chlorine. Like PCBs, dioxins areubiquitous environmental contaminants; they have been found in soil, surface water,sediment, plant and animal tissue worldwide. They have low water solubility andtherefore they are persistent in the soil for years. On the other hand, they are solublein lipids and tend to accumulate in the fat of animals and animal products (meat,fish, egg, milk) as well as in oil-bearing seeds and fruits. The European Commu-nity established maximum levels of 0.75 pg/g for the sum of dioxins and 1.5 pg/gfor the sum of dioxins and dioxin-like PCBs in vegetable oils and fats (CommissionRegulation (EC) No 1881/2006).</p><p>Similarly dangerous and widespread in industrial areas are the polycyclic aro-matic hydrocarbons (PAHs). They are considered to be carcinogens and, due to theirlipophilic characteristics, they can contaminate oils (Mafra et al. 2012).</p><p>The main sources are petroleum (petrogenic PAHs) and pyrolytic PAHs that areformed by incomplete combustion of organic materials and by combustion engines;they are widely found in industrial and municipal wastes and run-off. Electrogenicsystems, sometimes used to provide electric power to the mill, can also producePAHs. Moreover, the particulates generated by combustion can represent an effective</p></li><li><p>82 CH07 EXTRA-VIRGIN OLIVE OIL CONTAMINANTS</p><p>system for diffusion of PAHs adsorbed on the solid nanoparticles. The Interna-tional Olive Council and the European Community (RES-1/93-IV/05 2005; Com-m...</p></li></ul>