Application of a monoclonal-based immunoassay for the determination of imazalil in fruit juices

A monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) was developed for the quantification of imazalil [(RS)-1-(β-allyloxy-2,4-dichlorophenylethyl)imidazole] in apple, tomato and orange juice samples. From an imazalil hapten, which mimics the analyte structure, several monoclonal antibodies were obtained. An ELISA in the conjugate-coated format was developed and optimized using the antibody showing the highest sensitivity. For standards, the detection limit of the ELISA was 0.2 nM (0.06 ng ml^-1), with an I₅₀ value of 1.6 nM (0.5 ng ml^-1). The study of the influence of matrices on assay reliability indicated that the ELISA could determine imazalil in fruit juices at the low ng ml^-1 level simply by diluting the sample, without any clean-up or concentration step. Recovery and precision of the method were evaluated by spiking juice samples with imazalil in the 10-500 ng ml^-1 range. The mean recovery from fruit juices was 97% and the mean coefficient of variation was ∼20%. In addition to being precise and accurate, the method has proved to be simple and sensitive, with a quantification limit well below the maximum residue limits for imazalil in these matrices.     

Screening survey of deoxynivalenol in beer from the European market by an enzyme-linked immunosorbent assay

Deoxynivalenol (DON) was analysed in 313 beer samples collected from the European retail market using a commercially available immunoassay kit (enzyme-linked immunosorbent assay, ELISA). The incidence rate was about 87%, while most samples (73%) had contamination levels lower than 20 ng ml^-1. The contamination ranged between 4.0 and 56.7 ng ml^-1, with an average of 13.5 ng ml^-1. A statistically significant correlation between alcohol levels and DON contamination was found, as well as a significant difference between bottom, top and spontaneous fermenting beers. Twenty-seven beer samples were compared using a second ELISA kit and a good correlation was obtained between the two kits (r = 0.93). Although when compared with gas chromatography-mass spectrometry the ELISA tended to overestimate the results, a good correlation (r = 0.94) between the two methods was observed. Monitoring of DON in beer is important considering that DON production is dependent on the weather and that it can contribute significantly to the tolerable daily intake of DON, especially for frequent beer consumers.     

Occurrence of aflatoxin M1 in randomly selected North African milk and cheese samples

Forty-nine samples of raw cow's milk and 20 samples of fresh white soft cheese were collected directly from 20 local dairy factories in the north-west of Libya and analysed for the presence of aflatoxin M₁ (AFM₁). The samples were analysed using a high-performance liquid chromatography technique for toxin detection and quantification. Thirty-five of the 49 milk samples (71.4%) showed AFM₁ levels between 0.03 and 3.13 ng ml^-1 milk. Multiple analyses of five milk samples free of AFM₁ artificially contaminated with concentrations of AFM₁ at 0.01, 0.05, 0.1, 1.0 and 3.0 ng ml^-1 showed average recoveries of 66.85, 72.41, 83.29, 97.94 and 98.25%, with coefficients of variations of 3.77, 4.11, 1.57, 1.29 and 0.54%, respectively. Fifteen of 20 white soft cheese samples (75.0%) showed the presence of AFM₁ in concentrations between 0.11 and 0.52 ng g^-1 of cheese. Multiple assays of five cheese samples free of AFM₁ spiked with different concentration of AFM₁ (0.1, 0.5, 1.0 and 3.0 ng g^-1) showed average recoveries of 63.23, 78.14, 83.29 and 88.68%, with coefficients of variation of 1.53, 9.90, 4.87 and 3.79%, respectively. The concentrations of AFM₁ were lower in the cheese products than in the raw milk samples.     

Occurrence of ivermectin in bovine milk from the Brazilian retail market

High-performance liquid chromatography (HPLC) with fluorescence detection was used for the quantification of ivermectin residues in bovine milk intended for human consumption. After liquid-liquid extraction of ivermectin and purification of the extract, the compound was derivatized with 1-methylimidazol in N,N-dimethyl formamide to form a fluorescent derivative, which was separated by HPLC, using reversed-phase C₁₈, with methanol : water (96 : 4 v/v) mobile phase at a flow rate 0.7 ml min^-1. The excitation and emission wavelengths of the fluorescence detector were adjusted at 360 and 470 nm, respectively. The linearity of the method was in the range 10-100 ng ivermectin ml^-1. Based on a sample of 5.0 ml, the limit of detection and the limit of quantification for ivermectin in milk were 0.6 and 2 ng ml^-1, respectively. The recovery rate varied from 76.4 to 87.2%, with an average of 77.9 ± 3.2%, at four fortification levels. The inter-day precision of the method was 13% (n = 5). Of 168 samples analysed, 17.8% contained ivermectin above the limit of quantification. Nevertheless, none of the samples contained ivermectin above the maximum residue limit (10 ng ml^-1) established by the Brazilian Ministry of Agriculture.     

Determination of carbendazim residues in fruit juices by liquid chromatography-tandem mass spectrometry

In this paper a rapid optimized method for routine analysis of carbendazim residues in fruit juices is reported. The procedure is based on matrix solid-phase dispersion (MSPD) with diatomaceous earth and analysis of the extract by liquid chromatography-tandem mass spectrometry, with electrospray ionization (LC-ESI-MS/MS). In the method optimization, finding of the optimal pH for the extraction of carbendazim from juice was particularly critical. Significant matrix effects were observed, but could be eliminated using matrix-matched standards. High recoveries (82-102%), good repeatability (RSD ≤ 12%) and low limits of detection (0.03 ng ml^-1) and quantification (0.1 ng ml^-1) were achieved with this method.     

Simultaneous determination of aflatoxin B1 and ochratoxin A and their natural occurrence in Mediterranean virgin olive oil

Olive oil, the most important dietary fat source of the Mediterranean diet, can be contaminated by mycotoxins. An efficient analytical method for the simultaneous determination of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) in olive oil is reported. Thirty commercial samples of virgin olive oil, purchased in olive-press plants and supermarkets in southern Italy and North Africa, were analysed to verify the analytical procedure and monitor mycotoxin contamination. A simple, rapid and economic method was set up and tested for both the extractive step and the clean-up procedures for simultaneous AFB₁ and OTA determination in olive oil. Data obtained showed that OTA was detected with high frequency (80%) in samples from both geographical areas (up to 17.0 ng g^-1), while AFB₁ was found from three of four samples from North Africa (up to 2.4 ng g^-1). In addition, 'not labelled' oil samples proved to be more contaminated by OTA then 'labelled' samples (mean values of 2.47 and 0.66 ng g^-1, respectively). These findings indicate that olive oil can be significantly contaminated by mycotoxins and confirm that a scrupulous application of European Regulation 1019/2002 (European Commission 2002), which prohibits the sale of non-labelled olive oil, is strongly recommended. Conventional qualitative parameters such as peroxide number, spectrophotometric evaluation and acid values were not correlated with mycotoxin occurrence.     

N-methyl carbamate pesticide residues in conventional and organic infant foods available on the Canadian retail market, 2001-03

Seven parent N-methyl carbamate insecticides, in addition to two transformation products of aldicarb (aldicarb sulfoxide and aldicarb sulfone), and a single transformation product of carbofuran (3-hydroxycarbofuran) were measured in infant and junior foods available on the Canadian retail market between 2001 and 2003. Carbaryl and methomyl were the only analytes present at levels above the limits of detection in juice, cereals, fruit, vegetables or meat samples analysed. Carbaryl was the most frequently (7.6%) detected compound and concentrations ranged from 0.6 to 18 ng g^-1. Detectable levels of carbaryl were most frequently found in foods prepared with fruit. Methomyl was detected (0.8 ng g^-1) in one chicken with broth sample analysed in the present study. In all cases, the concentrations observed were orders of magnitude below the maximum residue limits established for these compounds in the corresponding raw food commodities in Canada (100-10 000 ng g^-1). Dietary intakes of carbaryl and methomyl based on the consumption of infant foods tested ranged between 0.2-343 and 0.4-2.0 ng kg^-1 body weight day^-1, respectively.     

Development of a lateral flow immunoassay strip for screening of sulfamonomethoxine residues

A rapid lateral flow immunoassay screening method has been developed for the determination of sulfamonomethoxine (SMM) residues in swine urine. For this purpose, a specific monoclonal antibody (mAb), SMM4B9 for SMM, was generated and characterized. The mAb showed low cross-reactivity (not larger than 0.3%) to other sulfonamides and other potentially occurring analytes. Based on the competitive immunoassay principle, the strip was developed with the mAb SMM4B9 and applied to the screening of SMM residues. The test strip is made up of a sample pad, a gold-conjugate SMM4B9 reagent pad, a blotted test membrane containing a test line, a control line (a nitrocellulose membrane spotted with SMM-BSA and goat anti-mouse antibody, respectively), and an absorbent pad. The test could be accomplished within 8-10 min. It was shown that the sensitivity of the test strip was as low as 5 ng ml^-1 of SMM and the half of maximal inhibition concentration (IC₅₀) was calculated to be 10.78 ± 0.22 ng ml^-1 by relative optical density. In unaided visual assessment the detection limit of the strip was 15 ng ml^-1. For samples spiked at 20 and 30 ng ml^-1 the coefficient of variation (CV (%)) was between 2.3 and 7.1%. When the test strip was compared with high-performance liquid chromatography (HPLC) analysis for naturally contaminated swine urine samples, the difference in results was less than 6.1%. The data suggest that the method has advantages of high sensitivity, specificity, simplicity and speed of performance, as well as the characteristics of repeatability, reproducibility or accuracy and assurance. Therefore, the test strip is suitable to determine SMM residues in swine urine rapidly and reliably by quantitative, semi-quantitative or qualitative detection.     

Variability in captan residues in apples from a Canadian orchard

Apple trees in an orchard in Quebec, Canada were treated, following label directions, with the fungicide captan (1,2,3,6-tetrahydro-N-(trichloromethylthio)phthalimide) during the 2003 agricultural season. A total of 142 apples from three rows of trees were selected for determination of captan by GC/MS. Individual apples were found to contain captan levels ranging from 16.9 to 6350 ng g^-1. Only two individual apple samples exceeded the Canadian maximum residue limit (5000 ng g^-1) for captan in apples. Six composite samples, comprising half portions of eight individual apples, were analysed from each of the three experimental rows. Composite samples ranged in concentration from 166 to 2620 ng g^-1. The greatest uncertainty associated with the measured concentrations was due to variability among apples rather than the measurement of residue levels.     

Determination of ochratoxin A in grapes of Greek origin by immunoaffinity and high-performance liquid chromatography

A simple analytical method for ochratoxin A (OTA) determination in grapes is described, using aqueous methanolic extraction, an immunoaffinity column clean-up step and high-performance liquid chromatography with fluorescence detection. Mean recovery was 94% (RSD = 4.0%) with a detection limit of 0.4 ng g^-1 and quantification limit of 1.20 ng g^-1. Repeatability (r) and reproducibility (R) were 1.17 and 1.34, respectively. OTA determinations were applied to 50 grape samples (23 different varieties) originating from representative regions of Greece. Results showed the presence of OTA in 86% of samples tested (n = 50). Traces were found in 56% of samples but OTA was not detectable in 14% of samples. Traces were also found in 4% of red, organically grown samples. The most contaminated were three samples of red grapes, two from Central Greece (2.69 and 1.41 ng g^-1), both table and wine-making grapes. The third sample (1.46 ng g^-1), originating from the island of Samos, was used only in wine-making. Mean (1.06 ng g^-1) and median (0.76 ng g^-1) OTA concentrations in red grapes were slightly higher compared to the mean (0.82 ng g^-1) and median (0.65 ng g^-1) concentrations in white grape samples. The study shows that the potential risk for a person of 60 kg ranged from 0.9 to 9 ng kg^-1 bw day^-1 and is dependent on the quantity of grapes consumed daily.     

Analysis of veterinary drug residues in fish and shrimp composites collected during the Canadian Total Diet Study, 1993-2004

Thirty shrimp, marine fish, freshwater fish, and canned fish composite samples collected and prepared as part of the Canadian Total Diet Study were analysed for 39 different veterinary drug residues. The analyses were undertaken to obtain baseline data that could be used to estimate the dietary exposure of Canadians to these residues. The most frequently observed residue was AOZ (four out of 30 samples), the metabolite of furazolidone, at a range of 0.50 to 2.0 ng g^-1 wet weight. Other residues detected included enrofloxacin (three samples; 0.3-0.73 ng g^-1), leucomalachite green (three samples; 0.73-1.2 ng g^-1), oxolinic acid (two samples; 0.3-4.3 ng g^-1), AMOZ (the metabolite of furaltadone; one sample; 0.40 ng g^-1), chloramphenicol (one sample; 0.40 ng g^-1), and SEM (the metabolite of nitrofurazone; one sample; 0.8 ng g^-1). The results of this survey indicate that Canadians are exposed to low ng g^-1 concentrations of some banned and unapproved veterinary drug residues via the consumption of certain fish and shrimp.     

Determination of ochratoxin A in virgin olive oils of Greek origin by immunoaffinity column clean-up and high-performance liquid chromatography

An improved specific analytical method for ochratoxin A (OTA) determination in olive oil is described, using a methanolic-aqueous extraction, an immunoaffinity column clean up step and high-pressure liquid chromatography with fluorescence detection. The mean recovery was found at 108% (relative standard deviation, RSD = 4.7%) and the detection limit (DL) was estimated at 4.6 ng kg^-1. Along with OTA, aflatoxin B₁ (AFB₁) was determined using the same extract. The recovery factor was 84.8% (RSD = 17.8%) and the DL was 56 ng kg^-1 olive oil. Both determinations were applied in 50 samples of olive oil originated from representative regions of Greece. Results revealed the presence of OTA in 88% of samples tested (n = 44, mean 267 ng kg^-1). Among them, 10 were contaminated with more than 500 ng kg^-1 (median 568 ng kg^-1), 10 with 200-500 ng kg^-1 (median 260 ng kg^-1), 15 with 100-200 ng kg^-1 (median 140 ng kg^-1), nine with DL-100 (median 60 ng kg^-1) and in six samples, OTA was not detectable. Interestingly, most contaminated samples were from Southern Greece. Results of AFB₁ determination showed the presence of aflatoxin B₁ (60 ng kg^-1) in only one olive oil sample also from Southern Greece. The levels of OTA found in Greek olive oil were relatively low as compared with other commodities such as cereals or wine reported in the literature.     

Occurrence of fumonisins B1 and B2 in asparagus from Shandong province, P.R. China

Thirty samples of asparagus spears were collected from the fields in Shandong province, China, in July 2004, and were analysed for the occurrence of fumonisins B₁ and B₂ (FB₁ and FB₂) by HPLC coupled with electrospray ionization tandem mass spectrometry. Twenty-four samples (80%) contained fumonisins, ranging from 24 to 670 ng g^-1 (average 123 ng g^-1) and 17 to 138 ng g^-1(average 35 ng g^-1) for FB₁ and FB₂, respectively. The total amount of fumonisins (FB₁ and FB₂) in all samples ranged from 47 to 714 ng g^-1 (average 158 ng g^-1) (based on dry weight). This is the first report on the natural occurrence of FB₁ and FB₂ in asparagus spears in China.     

Ochratoxin A in dried vine fruits on the Canadian retail market

Between 1998 and 2000, 151 samples of raisins and sultanas and two samples of currants were collected from retail outlets across Canada and analysed for ochratoxin A. Samples were extracted with methanol-sodium bicarbonate, and the extracts were cleaned-up by immunoaffinity column chromatography. Ochratoxin A was quantified by liquid chromatography with fluorescence detection. The minimum quantifiable level was 0.1 ng g^-1. Ochratoxin A was present, above the minimum quantifiable level, in 67 (79%) of 85 samples of raisins, in 39 (59%) of 66 samples of sultanas, and in both samples of currants. The overall mean level of ochratoxin A was 1.8 ng g^-1 in both the raisins and sultanas, and 2.8 ng g^-1 in the currants.     

Analysis of heat-processed corn foods for fumonisins and bound fumonisins

Thirty retail samples of heat-processed corn foods, i.e. corn flakes, corn-based breakfast cereals, tortilla chips and corn chips, were analysed for fumonisins — fumonisin B₁ (FB₁), fumonisin B₂ (FB₂) and hydrolysed FB₁ (HFB₁) — as well as for protein- and total-bound FB₁. Bound (hidden) fumonisins cannot be detected by conventional analysis. Improved methods for the determination of bound FB₁ were developed. The protein-bound FB₁ was extracted with 1% sodium dodecylsulfate (SDS) solution. The SDS, which interfered with high-performance liquid chromatography (HPLC) analysis, was then separated from protein-bound FB₁ by complexing with methylene blue followed by solvent extraction and hydrolysis with 2 N KOH. To measure total-bound FB₁, the sample itself was hydrolysed with KOH. In both cases, clean-up was accomplished on an OASIS polymeric solid-phase extraction column and the bound fumonisins were determined by HPLC measurement of HFB₁. Fourteen of 15 samples of corn flakes and other corn-based breakfast cereals analysed contained detectable levels of FB₁ with a mean in positive samples of 67 ng g^-1 (13-237 ng g^-1). Two samples also had detectable levels of FB₂ (21-23 ng g^-1). Bound FB₁ was found in all samples; the mean protein-bound FB₁ measured was 58 ng g^-1 (22-176 ng g^-1) and the mean total-bound FB₁ measured was 106 ng g^-1 (28-418 ng g^-1), reported as FB₁ equivalents after correction for recoveries of HFB₁. There was an average of about 1.3 times more FB₁ in the bound form compared with extractable FB₁, and this was about twice as much as protein-bound FB_1. Seven of the 15 samples of alkali-processed corn-based foods, such as tortilla chips and corn chips, contained FB₁ and three contained HFB₁ with means in measurable positive samples of 78 (48-134) and 29 (13-47) ng g^-1, respectively. Five of these alkali-processed corn foods contained bound FB₁; the mean measurable protein-bound FB₁ was 42 ng g^-1 (39-46 ng g^-1) and the mean measurable total-bound FB₁ was 100 ng g^-1(54-209 ng g^-1). HFB₁ derived from bound FB₁ in selected samples was confirmed by HPLC with mass spectrometry (MS).     

Public information campaign on aflatoxin contamination of maize grains in market stores in Benin, Ghana and Togo

Rotary International with the International Institute of Tropical Agriculture (IITA) conducted an information campaign from 2000 to 2004 to increase public awareness of aflatoxin in Benin, Ghana and Togo. Key informant interviews with 2416 respondents showed poor baseline knowledge of aflatoxin and its health risks. The campaign included monitoring of aflatoxin contamination in maize grains from market stores in 38 cities and towns. Aflatoxin concentration in contaminated samples ranged from 24 to 117.5 ng g^-1 in Benin, from 0.4 to 490.6 ng g^-1 in Ghana, and from 0.7 to 108.8 ng g^-1 in Togo. The campaign significantly increased public awareness that populations were exposed to high levels of aflatoxin. The number of maize traders who were informed about the toxin increased 10.3 and 3.2 times in Togo and Benin, respectively; at least 33% more traders believed the information in each of Benin and Togo; 11.4 and 28.4% more consumers sorted out and discarded bad grains in Benin and Ghana, respectively. This paper concludes that sustained public education can help reduce aflatoxin contamination.     

CONTAMINATION OF PATULIN IN CLEAR APPLE JUICE IN MASHHAD, IRAN

Patulin is a frequent contaminant of moldy and rotten apples and apple products. The aim of this study was to evaluate patulin contamination in 58 apple juices collected from a retail market in Mashhad during winter and spring of 2006.
Samples were assayed for patulin by high-performance liquid chromatography. Fifty-four samples were positive for patulin at levels that ranged from 10.5 to 121.8 µg/L, and six samples had patulin levels higher than 50 µg/L. The overall mean of patulin concentration was 29.2  ±  19.5 µg/L. Forty-eight samples had patulin concentration between 5 and 50 µg/L. Although the mean concentration of patulin samples was lower than Iranian maximum tolerated level of 50 µg/L, contamination of 10% of the samples at levels higher than 50 µg/L indicated the need for improving production techniques by the industry.

PRACTICAL APPLICATIONS

Studies have shown that the concentration of patulin may exceed the determined limits in apple juice and in other fruit products. Its presence can be a potential threat to the health of consumers, particularly children. The results may help us in understanding what should be the level of patulin in apple juice. The awareness of the apple industry of patulin contamination in fruit and the implementation of improved techniques for the production of apple products with reduced patulin concentrations have contributed to the quality of apple juice that are available on the Iranian market.     

Survey of aflatoxins in beer sold in Canada

Between March 1998 and March 2002, 304 samples of domestic (Canadian) and imported beers from 36 countries were picked up for the determination of aflatoxins B₁, B₂, G₁ and G₂. Twelve samples were positive with aflatoxins greater than the limit of quantitation (LOQ) (aflatoxin B₁, 4.4 ng l^-1; aflatoxin B₂, 3.4 ng l^-1; aflatoxin G₁, 11.2 ng l^-1; and aflatoxin G₂, 6.2 ng l^-1). Five samples from Mexico, two samples from Spain and one from Portugal contained aflatoxin B₁. Four samples from India contained aflatoxins B₁ and B₂. The remaining samples contained less than the LOQ for aflatoxins B₁, B₂, G₁ and G₂. The analytical method for this survey was based on that of Scott and Lawrence (Scott PM, Lawrence GA. 1997. Determination of aflatoxins in beer. Journal of AOAC International 80:1229-1234.). Aflatoxins B₁, B₂, G₁ and G₂ were determined at parts per trillion (ng l^-1) levels in beer by immunoaffinity column cleanup followed by derivatization with trifluoroacetic acid and reversed-phase liquid chromatography with fluorescence detection.     

Dioxins and polychlorinated biphenyls (PCBs) in fish oil dietary supplements: Occurrence and human exposure in the UK

Commercially available fish oil supplements sourced from retail outlets in the UK, as well as by mail order, were surveyed in 2000-02 for dioxin (PCDD/Fs) and polychlorinated biphenyl (PCB) content. Sampled products were representative of market share. The WHO-TEQ values for these products ranged from 0.18 to 8.4 ng kg^-1 for ΣPCDD/F and from 1.1 to 41 ng kg^-1 for Σ dioxin-like PCBs. The results suggest a downward trend in the levels of dioxins in fish oil supplements over the last decade, since levels for similar products ranged from 0.3 to 10 ng kg^-1 for ΣPCDD/F WHO-TEQ in 1996. Levels of ICES (International Council for the Exploration of the Seas) 7 PCBs in the current study ranged from 8.3 to 267 µg kg^-1. Subsequent to this survey, European Union legislation has been introduced that includes a maximum limit of 2 ng kg^-1 WHO-TEQ for dioxins in fish oil products for human consumption. Twelve of the 33 products reported here would have exceeded this limit. Negotiations are in progress to incorporate dioxin-like PCBs into the European Union regulations. When manufacturer-recommended doses were applied to the observed levels, the estimated upper bound human exposure to dioxins and dioxin-like PCBs from dietary intake of these products ranged from 0.02 to 7.1 pg WHO-TEQ kg^-1 body weight day^-1 for adults and from 0.02 to 10 pg WHO-TEQ kg^-1 body weight day^-1 for schoolchildren. This level rises to 1.8-8.9 pg WHO-TEQ kg^-1 body weight day^-1 for adults and 1.4-14 pg WHO-TEQ kg^-1 body weight day^-1 for schoolchildren when combined with the average exposure from the whole diet in 1997. Again, subsequent to this survey, the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) revised the UK tolerable daily intake (TDI) for mixtures of dioxins and dioxin-like PCBs from 10 to 2 pg WHO-TEQ kg^-1 body weight day^-1. This is in line with the tolerable weekly intake (TWI) of 14 pg WHO-TEQ kg^-1 body weight set by the Scientific Committee on Food (SCF).     

Non-dioxin-like PCBs in crops and related products: Levels and intakes in Serbia

Levels of six non-dioxin-like indicator PCBs in 36 composite samples of agricultural crops, related by-products and foodstuffs were pooled from a total of 938 individual samples collected in Serbia in 2002 and 2004. After extraction and cleanup, PCBs were determined by capillary GC using ECD. The highest total PCB levels were found in dried sugar beet pulp (2.89 ng g^-1 whole weight (ww)) and crude sunflower oil (1.83 ng g^-1 lipid), while the lowest levels were found in molasses (0.05 ng g^-1 ww). The calculated daily intake of PCBs for the crop products included in this study were compared with the maximum permissible risk (MPR) level established by the Dutch National Institute for Public Health and the Environment. Cereal products (flour, bread, pastry, pasta, cookies) were made a relatively large contribution (23% of MPR), while sugar (2% of MPR) and oil (4% of MPR) made a low and fairly uniform contribution to intake. The levels and intake of PCBs in Serbia were compared with data from other recent international surveys.