Evaluation of large volume-difficult matrix introduction-gas chromatography-time of flight-mass spectrometry (LV-DMI-GC-TOF-MS) for the determination of pesticides in fruit-based baby foods

The European Union Baby Food Directive (1999/39/EC), which came into force on 1 July 2002, set legal maximum residue levels at 0.01 mg kg^-1 for all pesticides in baby foods. The combination of large volume-difficult matrix introduction (LV-DMI) with gas chromatography-time of flight-mass spectrometry (GC-TOF-MS), described herein, provides the analyst with a simple but rapid alternative GC-MS technique for the multiresidue analysis of pesticides in fruit-based baby foods. Samples were extracted with ethyl acetate in the presence of Na₂SO₄ and NaHCO₃ and the crude extracts were analysed directly using LV-DMI-GC-TOF-MS. The best overall results (98 pesticides quantified satisfactorily at a spiking level of 0.01 mg kg^-1) were obtained by analysis of concentrated extracts (2.5 g crop ml^-1) using a 30-m column, with a chromatographic run time of 25 min. A good signal-to-noise ratio was obtained at the lowest calibrated level (0.0125 μg ml^-1), with excellent linearity achieved over the range 0.0125-0.25 μg ml^-1 (equivalent to 0.005-0.1 mg kg^-1). Average recoveries for the analysis of five replicate determinations at a spiking level of 0.01 mg kg^-1 were between 79 and 114% with relative standard derivations generally less than 20%.     

Persistent organochlorine pesticides in Mexican butter

Organochlorine pesticides have been used in Mexico in malaria control programmes against ectoparasites and as seed dresser. Owing to their chemical stability, they tend to accumulate in the lipid part of the organisms. The stored pesticides are excreted with the endogenous fat during milk production. The aim was to monitor the organochlorine pesticide levels in butter manufactured in Mexico. From the pesticides, only HCB, β-HCH, pp '-DDT, op '-DDT and pp '-DDE with major frequency and levels were detected. The HCB mean level was low at 0.008 mg kg -1 on a fat basis. From the HCH isomer, only the β-HCH at 0.065 mg kg^-1 on a fat basis was determined, remaining as the main contaminant of the monitored butters. Among DDTs, pp '-DDE was the major constituent (0.043 mg kg^-1 on a fat basis) followed by pp '-DDT (0.036 mg kg^-1) and op '-DDT (0.009 mg kg^-1). Comparing the previous study (1994) and this one (2001), all organochlorine pesticides had a descendent tendency; β-HCH decreased from 0.095 to 0.065 mg kg^-1 on a fat basis, whereas the total DDT decreased from 0.056 to 0.047 mg kg^-1, pp '-DDT from 0.050 to 0.036 mg kg^-1, op '-DDT from 0.018 to 0.009 mg kg^-1, while pp '-DDE increased from 0.032 to 0.043 mg kg^-1. The decreased DDT levels in Mexican butters is caused by the substitution of organochlorine insecticides with pyrethroids used by the Mexican Ministry of Health since 1999 in sanitary programmes.     

Natural co-occurrence of deoxynivalenol and fumonisins B1 and B2 in Italian marketed foodstuffs

A survey was performed to obtain the frequency and levels of contamination by deoxynivalenol (DON) and fumonisins B₁ and B₂ (FB1, FB2) mycotoxins in Italian marketed foods. Of 202 samples investigated, including raw materials and processed cereal foods (bread, pasta, breakfast cereals, biscuits, baby and infant foods), 84% were contaminated with DON at levels from 0.007 to 0.930 μg g^-1 (median 0.065 μg g^-1); 26% contained FB1 ranging from 0.010 to 2.870 μg g^-1 (0.070 μg g^-1); 35% contained FB2 at 0.010-0.790 μg g^-1 (0.080 μg g^-1). The highest levels of DON and FB1 were detected in raw cereals and wholemeal flours. The highest levels of FB2 were detected in durum wheat pasta. A widespread DON contamination was found in baby and infant foods at levels varying from 0.007 to 0.166 μg g^-1.     

Study on the effect of grain storage and processing on deltamethrin residues in post-harvest treated wheat with regard to baby-food safety requirements

The effects of storage intervals and of milling procedures on dissipation of deltamethrin residues in post-harvest treated wheat grain were studied with the aim to obtain scientific data on compliance of the processed products with the safety requirements concerning baby foods. The insecticide formulation was applied on stored wheat at a recommended rate of active ingredient of 0.5 mg kg^-1 and at a higher rate of 4 mg kg^-1, performing the highest protective effect. The dissipation of residues and their distribution in different fractions of the milled grain were studied after various storage intervals, from 7 to 270 days after treatment. Eight fractions—bran, semolina, three types of groats, and three types of flour—were collected after milling of grain and analysed for determination of pesticide residues. The residues were determined by gas chromatography characterized by the limit of determination of 0.005 mg kg^-1, low enough for enforcement of the maximum residue level of 0.01 mg kg^-1 established by the European Commission Directive for any pesticide in cereal-based foods. Deltamethrin applied post-harvest on wheat as grain protectant was distinguished by low rate of degradation on the grain under practical storage conditions. One hundred and eighty days after treatment at an application rate of 0.5 mg kg^-1, the residues were between 0.03 and 0.2 mg kg^-1 in the various types of flour. Two hundred and seventy days after treatment at a rate of 4 mg kg^-1, the residues in the flour were in the range of 0.4-1.5 mg kg^-1.     

Residue formation of fumonisin B1 in porcine tissues

The residues derived from the uptake of fumonisin B1, a toxic metabolite of Fusarium verticillioides frequently occurring in corn and corn products, were determined in growing pigs. After oral administration of 100 mg FB₁/animal/day for 5-11 days, serum, bile, lung, liver, kidney, brain, spleen, pancreas, heart, muscle, eye, and fat samples were collected immediately and analysed by LC-MS. The highest values were measured in kidney (833 ±1329 μg kg^-1, mean ±SD), liver (231 ±163 μg kg^-1), lung (170 ±311 μg kg^-1) and spleen (854 ±2212 μg kg^-1). Muscle contained 26 ±41 μg kg^-1, while in fat only 2 ±3 μg kg^-1 were traceable. Despite the potential accumulation over extended feeding periods as well as the large variations in the residue formation of FB₁, a carry-over in edible tissues from swine was considered not to be of toxicological relevance.     

Pesticide residues in the Canadian Market Basket Survey 1992 to 1996

Market basket food samples from six Canadian cities collected from 1992 to 1996 were analysed for pesticide residues. One hundred and thirty-six composites were prepared for each city, representing 99% of the Canadian diet. Residues were found most frequently in peanut butter and butter. DDE, malathion and captan occurred most frequently, while the fungicides chlorothalonil, dicloran and captan were present in the highest concentrations. Processed commodities contained fewer residues and at lower concentrations than the raw products. No residues were detected in either milk or soy-based infant formula. Of the infant foods sampled, fruit contained both the greatest number and highest concentrations of pesticides.     

Effect of grain storage and processing on chlorpyrifos-methyl and pirimiphos-methyl residues in post-harvest-treated wheat with regard to baby food safety requirements

A study was undertaken to assess the effects of storage intervals and of milling procedures on the dissipation of chlorpyrifos-methyl and pirimiphos-methyl residues in post-harvest-treated wheat grain and to obtain scientific data on the compliance of the processed products with safety requirements concerning baby foods. The insecticide formulations were applied on stored wheat at recommended rates (20 ml t^-1). The initial concentration levels in whole grain were determined in samples taken 1 h after treatment. The dissipation of residues and their distribution in different fractions of the milled grain were studied after various storage intervals, from 7 to 270 days after treatment. Samples of treated grain were milled in a fractionating laboratory mill and eight fractions — bran, semolina, three types of groats and three types of flour — were collected and analysed for pesticide residues. The residues were determined by an analytical method based on acetone extraction, graphitized carbon clean-up and GC-ECD, respectively, and GC-NPD determination of residues. The limits of determination of both pesticides were 0.005 mg kg^-1, which is high enough for enforcement of the European Commission Directive that established a maximum residue level of 0.01 mg kg^-1 for any pesticide in cereal-based baby food. The results showed that the pesticides chlorpyrifos-methyl and pirimiphos-methyl applied post-harvest on wheat as grain protectants were distinguished by relatively low rates of degradation in the grain under practical storage conditions. Milling did not significantly reduce the bulk of the chemicals but resulted in the distribution of residues in various processed products. The main part of the insecticides deposited on the grain remained in the bran and partly in semolina fractions. After 270 days of treatment, the residues of chlorpyrifos-methyl were within the range 0.8-2.1 mg kg^-1 and of pirimiphos-methyl — between 0.6 and 3.7 mg kg^-1 in the various types of flour.     

Survey of total mercury in total diet food composites and an estimation of the dietary intake of mercury by adults and children from two Canadian cities, 1998-2000

Total mercury was measured in 259 total diet food composites from two Canadian cities. Levels were generally low, with 46% of the composites having concentrations below the limit of detection, which ranged from 0.026 to 0.506 ng g^-1. The fish category contained the highest mercury concentrations, which averaged 67 ng g^-1 and ranged from 24 to 148 ng g^-1. All composites were below the Canadian guideline for total mercury in fish of 0.5 ppm. Dietary intakes of mercury averaged 0.022 μg kg^-1 body weight/day (μg kg^-1 day^-1), and ranged from 0.012 μg kg^-1 day^-1 for females over 65 years old to 0.062 μg kg^-1 day^-1 for 0-1-month-old infants. For fish consumers, fish contributed to more than half of the ingested mercury. All intakes were well below Joint FAO/WHO Expert Committee on Food Additives Provisional Tolerable Weekly Intakes, expressed on a daily basis, of 0.71 μg kg^-1 day^-1 total mercury and 0.47 μg kg^-1 day^-1 methyl mercury, and also below a recent Health Canada recommended maximum methyl mercury intake of 0.2 μg kg^-1 day^-1 for children and women of child-bearing age.     

Analysis and monitoring of chloramphenicol residues in food of animal origin in Slovenia from 1991 to 2000

To prevent the illegal use of chloramphenicol (CAP), regulatory control of its residues in food of animal origin is essential. In Slovenia, the monitoring of CAP residues for statutory purpose started in 1991. The results of a 10-year period are presented. CAP residues were determined by capillary gas chromatography (GC) with electron capture detection (ECD) using meta-CAP as an internal standard (ISTD). Before chromatographic determination, analytes were derivatized by silylation. Overall, CAP recovery, adjusted for ISTD, was for bovine muscle tissue and raw cow's milk (in the region of 2-10 μg kg^-1) 89 and 102%, respectively, and for whole eggs, 87% (in the region of 1-10 μg kg^-1). The use of meta-CAP improved significantly the precision of the method. The detection limit for CAP was 1 μg kg^-1, which was sufficiently sensitive for routine use. A total of 1308 random samples of Slovenian origin were analysed from 1991 to 2000, covering all parts of the country. CAP was found only in one milk sample in 1997 at a concentration of 4.6 μg kg^-1.     

Australian survey of acrylamide in carbohydrate-based foods

A method was developed and validated for the determination of acrylamide in carbohydrate-based foods. Solid-phase extraction employing a mixed-bed anion and cation exchange cartridge in series with a C18 extraction disk was used to clean-up water extracts of food samples before analysis by liquid chromatography coupled with tandem mass spectrometry detection. The limit of detection was calculated as approximately 25 μg kg^-1 and the limit of reporting was 50 μg kg^-1. The average method recovery for 84 samples from a range of matrices reporting was 99% with a relative standard deviation of 11.2%. A survey was conducted of 112 samples of carbohydrate-based foods composited from 547 products available in the Australian market. The analytical results were used in conjunction with Australian food consumption data derived from the 1995 National Nutrition Survey (NNS) to prepare preliminary dietary exposure estimates of Australians to acrylamide through only the food groups examined. Mean dietary exposure to acrylamide resulting from consumption of the foods tested, for Australians aged 2 years and above, was estimated as 22-29 µg day^-1 (equivalent to 0.4-0.5 µg kg^-1 bodyweight day^-1) and between 73 and 80 µg day^-1 (1.4 and 1.5 µg kg^-1 bodyweight day^-1) for 95th percentile consumers. Young children (2-6 years) consuming acrylamide-containing foods had a higher acrylamide exposure on a per kilogram bodyweight basis (mean 1.0-1.3 µg kg^-1 bodyweight day^-1). The estimated exposure of Australians to acrylamide is similar to that estimated for other countries.     

Deoxynivalenol and other Fusarium toxins in wheat and rye flours on the Danish market

Information on the contamination of Danish cereals and cereal products with Fusarium toxins is limited and the last survey is from 1984/1985. In the present study, the occurrence of deoxynivalenol (DON), nivalenol (NIV), HT-2 toxin, T-2 toxin and zearalenone (ZON) was investigated in flour of common wheat, durum wheat and rye. The samples were collected from 1998 to 2001 from both mills and the retail market in Denmark. A total of 190 flour samples were analysed for DON and NIV and about 60 samples for HT-2, T-2 toxin and ZON. DON was most frequently detected with an incidence rate of 78% over all samples for all years. The contamination level varied considerably from year to year, and for wheat and rye the highest incidence and DON concentrations were found in samples from the 1998 harvest. There were regular and heavy rainfalls in Denmark during the flowering period of the crops that year, and DON was found in all samples, with mean concentrations in wheat and rye flour of 191 μg kg^-1 (n =14) and 99 μg kg^-1 (n =16), respectively. Comparison of data from each harvest year showed higher contents of DON in samples of wheat (range 20-527 μg kg^-1) than in rye (20-257 μg kg^-1). Contents of NIV, HT-2 toxin and ZON in samples of wheat and rye were generally low, and even in positive samples the contents were close to the detection limit of the methods. The T-2 toxin was detected in only a few of the wheat samples and in low amounts. However, the toxin was found in about 50% of the rye samples collected during 1998-2000, with a mean content of 49 μg kg^-1 (n =25). Durum wheat flour showed the highest DON contamination level, and all samples (n =33) collected during 2000 and 2001 contained DON with means and medians above 1100 μg kg^-1. Over 70% of the samples contained more than 500 μg kg^-1 DON, and the highest observed concentration was 2591 μg kg^-1. The concentration of T-2 toxin in durum wheat flour was also high with five of the 10 analysed samples containing more than 100 g kg^-1.     

Acrylamide in Asian foods in Hong Kong

About 400 food samples, mainly Asian foods available in Hong Kong, were tested for acrylamide by an LC-MS/MS method using [1, 2, 3-¹³C₃]-acrylamide as surrogate. The acrylamide levels in the more commonly consumed food items in the food groups such as rice and rice products, noodles, bakery and batter-based products, were generally less than 60 μg kg^-1. Higher levels were found in the food groups such as biscuit-related products and crisps. The highest levels were detected in potato crisps (1500-1700 μg kg^-1). Lower levels were found in rye flour-based crisps (440 μg kg^-1), followed by corn-based (65 to 230 μg kg^-1) and wheat flour-based crisps (61-200 μg kg^-1), and then rice flour-based crisps (15-42 μg kg^-1). The acrylamide formation during deep frying of a wheat flour-based product, Chinese fried fritter, was studied. Deep-frying at 170°C resulted in gentle but steady rise in acrylamide content. A steep rise for frying at 210°C was recorded. The moisture content of the product decreased with frying time, but the fat content increased. It is proposed that the reaction for the formation of acrylamide was initiated on the surface and then penetrated into the interior of the food matrix by heat transfer via radiation/conduction and diffusion of hot oil.     

Survey of ochratoxin A and deoxynivalenol in stored grains from the 1999 harvest in the UK

Three hundred and twenty samples from the 1999 UK harvest comprising wheat (201 samples), barley (106) and oats (13) were analysed for ochratoxin A and deoxynivalenol. A small number of organic samples was also obtained. Samples were collected from farms, central stores, mills, maltings and ports from across the UK from February to April 2000. Ochratoxin A and deoxynivalenol analysis was by affinity column clean up and high-performance liquid chromatography with fluorescence and ultraviolet light detection, respectively, with limits of detection of 0.2 and 20 μg kg^-1. The survey found ochratoxin A at below 5 μg kg^-1 in 97% of the samples indicating satisfactory storage conditions. The remaining 3% of the samples contained ochratoxin A at levels between 5.2 and 231 μg kg^-1, but none of these samples was intended for human consumption. Deoxynivalenol was detected in 88% of all samples, with 83% below 100 μg kg^-1; the maximum level was 600 μg kg^-1. Twenty samples containing deoxynivalenol at or above 150 μg kg^-1 by high-performance liquid chromatography were all confirmed by gas chromatography/mass spectrometry. Nivalenol was also detected by gas chromatography/mass spectrometry at levels of 50 μg kg^-1 or higher in 18 of 20 samples where deoxynivalenol was confirmed.     

Occurrence of aflatoxin M1 in domestic milk in Japan during the winter season

A total of 208 samples of commercial pasteurized milk gathered from retail outlets across Japan during the winter season were analysed for aflatoxin M₁ (AFM₁). Japan was divided into 11 regions from north to south, and nine to 45 milk samples from each region were randomly purchased between December 2001 and February 2002. Each milk sample was cleaned up by an immunoaffinity column, and AFM₁ was quantified by liquid chromatography with fluorescence detection in four independent laboratories. The limit of detection of the method was 0.001 μg kg^-1. The identity of the putative AFM₁ in milk sample was confirmed by the formation of AFM₁ hemi-acetal with trifluoroacetic acid. Based on the results obtained with spiked samples (0.05 μg AFM₁ kg^-1), the mean recovery was 91.4%, the relative standard deviation for repeatability was 4.6%, and the relative standard deviation for reproducibility was 8.0% among four independent laboratories. AFM₁ was detected in 207 (99.5%) of 208 milk samples at 0.001-0.029 μg kg^-1, with a mean of 0.009 μg kg^-1 and a 90th percentile of 0.014 μg kg^-1. No significant difference of the level of AFM₁ contamination was observed among the regions.     

Occurrence of aflatoxins in layer feed and corn samples in Konya province, Turkey

The natural occurrence ofaflatoxin was investigated in layer feed and corn samples brought to Konya Veterinary Control and Research Institute Laboratory between 15 April and 15 December 2002. Seventy-eight samples (52 feeds, 26 corn samples) were analysed for total aflatoxin (B₁ + B₂ + G₁ + G₂) by an ELISA screening method. Aflatoxin contamination was determined in 37 feed samples (71.1%) and 15 corn samples (57.7%), with a range of1.5-133 μg kg^-1. However, a majority ofthe aflatoxin contamination was less than 5 μg kg^-1 (50% within the positive samples). Two feed samples and two corn samples exceeded the maximum tolerated levels in feed (20 μg kg^-1) and feedstuffs (50 μg kg^-1) for total flatoxin.     

Migration of trimellitic acid from epoxy anhydride can coatings into foods

The migration of trimellitic acid and its esters from epoxy anhydride coatings was determined in simulants as well as in canned foods. The most appropriate simulant was a combination of EC simulants B and C: 2% acetic acid/10% ethanol in water. The average migration into food was 900 μg kg^-1. This far exceeds the 50 μg kg^-1 for which the safety of trimellitic acid and its anhydride is ensured and the Swiss legal limit (QM(T) of 5 mg kg^-1 coating). Furthermore, much trimellitic acid migrated as (unidentified) esters, i.e. toxicological testing of free trimellitic acid is inadequate for the material that in reality migrates.     

Determination of Some Endocrine-Disrupting Metals and Organochlorinated Pesticide Residues in Baby Food and Infant Formula in Turkish Markets

There is a paucity of data in respect of the nutritional quality of complementary foods for infants and young children aged between 6 and 12 months. In this study, we developed and validated an analytical method for determination of the endocrine-disrupting organochlorine pesticides (OCPs) and elements (As, Cd, and Pb) in infant formula and baby foods. Therefore, it found out the contamination level of the both OCPs and some trace metals (As, Cd, and Pb) in widely consumed infant formula and baby food in Turkey. Metal concentrations in baby foods and infant formula were determined by inductively coupled plasma mass spectrometry. Samples were digested with nitric acid and hydrogen peroxide in a microwave oven. Determination of 24 organochlorine pesticide residues in baby foods and infant formula was completed by using gas chromatography double mass spectrometry. QuEChERS extraction method was carried out in the sample preparation part. The analytical performance of the entire procedure, such as linearity, the detection of limit, limit of quantification, specificity/selectivity, recovery (%), and precision, were assessed. The recoveries ranged from 93% (As) to 100% (Pb) for elements 78–98% for organochlorine pesticide residues (OCPs) at 100 ng mL^?1. According to the results, lead, cadmium, and pesticides were not detected in any of the samples, while arsenic was detected in 16 samples.     

Nitrates and nitrites in vegetables and vegetable-based products and their intakes by the Estonian population

The content of nitrates were determined in 1349 samples of vegetables and ready-made food in 2003-2004 as a part of the Estonian food safety monitoring programme and the Estonian Science Foundation grant research activities. The results of manufacturers' analyses carried out for internal monitoring were included in the study. The highest mean values of nitrates were detected in dill, spinach, lettuce and beetroot. The mean concentrations were 2936, 2508, 2167 and 1446 mg kg^-1, respectively. The content of nitrites in samples was lower than 5 mg kg^-1. In total, the mean intake of nitrates by the Estonian population was 58 mg day^-1. The mean content of nitrates in vegetable-based infant foods of Estonian origin was 88 mg kg^-1. The average daily intake of nitrates by children in the age group of 4-6 years was 30 mg. The infants' average daily intake of nitrates from consumption of vegetable-based foods was 7.8 mg.     

Multiresidue analysis of pesticides in agricultural products by GC/MS,GC-ECD and GC-FTD using acetonitrile extraction and clean-up with mini-columns

An analytical method was developed for determination of organochlorine, pyrethroid and nitrogen-containing pesticide residues in agricultural products by GC/MS, GC-ECD and GC-FTD. Pesticides were extracted with acetonitrile, and the organic layer was cleaned up on C18 and ENVI-Carb/LC-NH2 cartridges. Pesticides were determined by GC/MS, GC-ECD and GC-FTD. Detection limits of pesticides by GC/MS and GC were below 1-30 ng/g and 1-3 ng/g, respectively. Recoveries of 27 out of 53 pesticides determined by GC/MS and 47 out of 53 determined by GC were 70-120%. This method was useful for the multiresidue analysis of pesticides in agricultural products. Pesticide residues in 81 domestic crops were investigated from April 2001 to March 2002. Residues of 31 pesticides were detected from 21 crops.     

Natural contamination of oat with group A trichothecene mycotoxins in Poland

Ninety-nine naturally contaminated oat grain samples were collected in 12 plant breeding stations in different parts of Poland. T-2 toxin, HT-2 toxin and diacetoxyscirpenol (DAS) levels were determined by gas chromatography with mass selective detection (GC-MS). HT-2 was the major toxin with an incidence of 24% and its average level in positive samples was 21 μg kg^-1. The incidence of T-2 and DAS was 15 and 12%, and their average levels were 60 and 23 μg kg^-1, respectively. The highest concentrations of HT-2, T-2 and DAS were 47, 703 and 111 μg kg^-1, respectively. Sixty-five samples were free of detectable amounts of the toxic metabolites analysed.