Pesticides in foodstuffs

Owing to the complexity of multi-residue methods for products of animal origin, it is not possible to outline a simple scheme however, readers should refer to methods described in two references for detailed guidance (Analytical Methods for Pesticides in Foodstuffs, Dutch method collection and European Norm EN 1528. ) There is no multi-method specifically designed for body fluids and tissues. The latter matrix can be partly covered by methods for products of animal origin. However, an approach published by Frenzel et al may be helpful (method principle whole blood is hemolyzed and then deproteinized. After extraction of the supernatant, the a.i. is determined by GC/MS. The LOQ is in the range 30-200 ag depending on the a.i.). 

Analytical Methods for Residues of Pesticides in Foodstuffs, fifth edition, Rijswiik (1988) amended by Analytical Methods for Pesticide Residues in Foodstuffs, ed. P. van Zoonen, sixth edition. General Inspectorate for Health Protection, The Hague (1996). 

Biosensors ai e widely used to the detection of hazardous contaminants in foodstuffs, soil and fresh waters. Due to high sensitivity, simple design, low cost and real-time measurement mode biosensors ai e considered as an alternative to conventional analytical techniques, e.g. GC or HPLC. Although the sensitivity and selectivity of contaminant detection is mainly determined by a biological component, i.e. enzyme or antibodies, the biosensor performance can be efficiently controlled by the optimization of its assembly and working conditions. In this report, the prospects to the improvement of pesticide detection with cholinesterase sensors based on modified screen-printed electrodes are summarized. The following opportunities for the controlled improvement of analytical characteristics of anticholinesterase pesticides ai e discussed ... 

Egan H, Holmes DC, Roburn J, et al. 1966. Pesticide residues in foodstuffs in Great Britain II. Persistent organochlorine pesticide residues in selected foods. J Sci Food Agric 17 563-569. 

EEC Directive on pesticide residues in foodstuffs of animal origin... 

Pesticide residue levels in foodstuffs are generally regulated in order to ... 

Committee for Analytical Methods for Residue of Pesticides and Veterinarian Products in Foodstuffs by Headspace Method, of MAFF, Report by the Panel of the Determination of Dithiocar-bamate Residues, Ana/yit, 106,781 (1981). 

Multi-residue Method S19 of the DFG Manual,including Cieanup Procedure Xll-6 (gel-chromatographic cleanup), has been used successfully in many laboratories because of its broad applicability for the gas-chromatographic determination of pesticide residues in foodstuffs. DFG method S19 is also included in the respective European Standards. Subsequently, a modification of the extraction and partition step has been implemented. The modified method requires less experimental effort and eliminates the use of dichloromethane, which is an undesirable solvent for toxicological and ecological reasons. As the results from validation studies demonstrate,... 

HPLC has had considerable success in separating compounds as diverse as steroids, carbohydrates, vitamins, dyestuffs, pesticides and polymers. It is used routinely for the assay of pharmaceutical products, the monitoring of drugs and metabolites in body fluids and for other biomedical, biochemical and forensic applications, such as the detection of drugs of abuse. The determination of additives in foodstuffs and beverages including sugars,... 

Panel 2 of the Committee for Analytical Methods for Residues of Pesticides and Veterinary Products in Foodstuffs of the Ministry of Agriculture, Fisheries and Food (1976) Analyst 101 386. 

This chapter briefly describes how European Community (EC) legislation on chemical contaminants in foodstuffs is developed, adopted and enforced. In this context the term chemical contaminants covers residues of pesticides and veterinary dmgs, heavy metals, mycotoxins and nitrate. 

The DG SANCO s Working Group on Pesticide Residues proposes MRLs for pesticide residues in foodstuffs. For each pesticide, MRLs are proposed for residues in the relevant individual commodities/crops. Since a large number of pesticides have to be dealt with, the workload is spread by appointing each Member State in the Working Group as Rapporteur for a number of specified pesticides. 

Enforcement of EC regulations on pesticide residues in foodstuffs is the responsibility of the competent authorities in the Member States. The authorities in each Member State should ensure that the products produced in that country and those imported directly from countries outside the EU ( Third Countries ) comply with EC legislation. In principle, when such a system is fully developed and operational in all Member States, there should be no real need for countries to examine products coming from other Member States. 

Lu, D.S., Yu, C., et al., 2000. Analysis on dynamic trends of organochlorine pesticide residues in foodstuff of Zhejiang province. China Public Health (Chinese) 16, 1027-1029. 

Nakata, H., Kawazoe, M., et al., 2002. Organochlorine pesticides and polychlorinated biphenyl residues in foodstuffs and human tissues from China Status of contamination, historical trend and human dietary exposure. Arch. Environ. Contain. Toxicol. 43, 473-480. 

Xiao, B.M., Lin, X.L., et al., 1999. Analysis on residues of organochlorine pesticides from foodstuff in the Northeast China area. Chinese Primary Health Care (Chinese) 13, 35-36. 

Kannan, K., Tanabe, S., Giesy, J.P., Tatsukawa, R., 1997. Organochlorine pesticides and polychlorinated bipehnyls in foodstuffs from Asian developing countries. Rev. Environ. Contam. Toxicol. 152, 1-55. 

Tanabe, S., Kannan, K., Tabucanon, M.S., Siriwong, C., Ambe, Y., Tatsukawa, R., 1991. Organochlorine pesticide and polychlorinated biphenyl residues in foodstuffs from Bangkok, Thailand. Environ. Pollut. 72, 191-203. 

Another organophosphorus insecticide, Bayrusil (XIII) becomes fluorescent upon heat treatment but the fluorescence yield is less than with coumaphos (around 0.01 yg/spot) (4 4). This pesticide has also been analysed in foodstuffs at the 0.02 ppm level (46 ). ... 

Bowman and Beroza [472] hydrolysed carbamates by heating with 10% NaOH solution and condensed the phenol produced with chlorothiophosphate in the presence of pyridine (Scheme 5.37). The resulting derivative is highly specific for the compound under analysis and, with the use of a flame photometric detector, it permits its sensitive analysis (at the level of hundredths of 1 ppm in foodstuffs). A column packed with 10% of DC-200 was used for the analysis at 190°C. Holden et al. [473] also obtained a high sensitivity in the analysis of N-methyl- and dimethylcarbamates if they condensed amines released by alkaline hydrolysis with l-fluoro-2,4-dinitrobenzene and applied an ECD for detection (2% of XE-60, 190°C). Different substituted anilines were similarly analysed as products from the decomposition of different pesticides [474] in the form of different perfluorinated acyl derivatives. 

If there is no choice in using pesticides in agriculture, there is also no choice about adequate monitoring of all of our foodstuffs or about setting valid tolerances for pesticides on foods. We cannot afford even one mistake which involves all or most of the population. 

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