Food Safety Magazine, February/March 2013

TestingBy Katerina Mastovska, Ph.D.Modern Analysis of ChemicalContaminants in FoodAn essential component offood safety testingChemical contaminants may occur in our foodfrom various sources. They typically pose ahealth concern, resulting in strict regulationsof their levels by national governments andinternationally by the Codex AlimentariusCommission. Therefore, analysis of relevant chemicalcontaminants is an essential part of food safety testingprograms to ensure consumer safety and compliance withregulatory limits. Modern analytical techniques can determineknown chemical contaminants in complex foodmatrices at very low concentration levels. Moreover, theycan also help discover and identify new or unexpectedchemical contaminants.Sources of Chemical Contaminants in FoodChemical contaminants can be present in foods mainlyas a result of the use of agrochemicals, such as residuesof pesticides and veterinary drugs, contamination fromenvironmental sources (water, air or soil pollution), crosscontaminationor formation during food processing,migration from food packaging materials, presence orcontamination by natural toxins or use of unapprovedfood additives and adulterants.Pesticide ResiduesThe use of pesticides, such as insecticides, fungicidesor herbicides, has become an integral part of modernagriculture to increase crop yields and quality by controllingvarious pests, diseases and weeds. Registration of newpesticides is a strictly regulated processthat evaluates their toxicity and environmentalfate, and sets maximum residuelimits (tolerances) in raw and processedcommodities. There are over 1,400known pesticides. Some of them shouldno longer be used but may still be presentin the environment. Older pesticidesare being reevaluated based on currentlyavailable scientific data.Approved uses of pesticides followingGood Agricultural Practices should resultin pesticide residues below maximumresidue limits established in a givencountry. However, global sourcing of rawcommodities and global distribution offood products complicate the situationbecause pesticide registrations, uses andlimits can be and are different in differentcountries. Consequently, an approveduse in one country may result inan illegal pesticide residue in a food importedinto another country, such as therecent case of the fungicide carbendazimin orange juice imported into the UnitedStates from Brazil. Furthermore, pesticidescan be misused or present in fooddue to contamination during application(spray drift), storage or transportationor from environmental sources, such ascontaminated water or soil.Veterinary Drug ResiduesSimilar to pesticides, veterinary drugsare agrochemicals that undergo a thoroughregistration process, resulting insetting of their maximum residue limits/tolerances in animal-derived foods. Themajor classes of veterinary drugs includeantibiotics, anthelmintics, coccidiostats,nonsteroidal anti-inflammatory drugs,sedatives, corticosteroids, beta-agonistsand anabolic hormones. These drugs,which are administered to live animals,can remain as residues in animal tissues.Liver and kidney are highly susceptibleto residues given their biological function.Certain antibiotics, such as penicil-12 F o o d S a f e t y M a g a z i n e