Determination of phthalates in raw bovine milk by gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS) and dietary intakes

Low levels of phthalates, including di(2-ethylhexyl) phthalate (DEHP), in raw bovine milk were determined using gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS). A fast and convenient process of sample treatment combined with TOF-MS analysis (medium resolution >5000), yielded good recoveries (85–125%) and low limits of detection (<0.002 mg kg^?1). The most commonly used phthalate, DEHP, was found in 15 out of 30 samples monitored in this study. DEHP concentrations in raw milk ranged from not detected to 0.154 mg kg^?1, and the mean concentration was 0.057 mg kg^?1. The dietary intake of DEHP was about 0.004 mg kg^?1 body weight day^?1 if a child (24 months, 13 kg body weight) drinks 1 L day^?1 of milk that contains the mean concentration of DEHP found in raw milk. The estimated dietary intake corresponded to 8% of the European Union tolerable daily intake (TDI) of 0.05 mg kg^?1 body weight day^?1. Dimethyl phthalate (DMP) and di-n-butyl phthalate (DBP) were found from two and 20 samples, respectively, at low levels. Diethyl phthalate (DEP), butylbenzyl phthalate (BBP), and di-n-octyl phthalate (DnOP) were not found in any of the samples.     

Migration of epoxidized soybean oil (ESBO) and phthalates from twist closures into food and enforcement of the overall migration limit

Nineteen samples of food in glass jars with twist closures were collected by the national food inspectors at Danish food producers and a few importers, focusing on fatty food, such as vegetables in oil, herring in dressing or pickle, soft spreadable cheese, cream, dressings, peanut butter, sauces and infant food. The composition of the plasticizers in the gaskets was analysed by gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Epoxidized soybean oil (ESBO) and phthalates were determined in the homogenized food samples. ESBO was the principal plasticizer in five of the gaskets; in 14 it was phthalates. ESBO was found in seven of the food samples at concentrations from 6 to 100 mg kg^?1. The highest levels (91–100 mg kg^?1) were in oily foods such as garlic, chilli or olives in oil. Phthalates, i.e. di-iso-decylphthalate (DIDP) and di-iso-nonylphthalates (DINP), were found in seven samples at 6–173 mg kg^?1. The highest concentrations (99–173 mg kg^?1) were in products of garlic and tomatoes in oil and in fatty food products such as sauce béarnaise and peanut butter. For five of the samples the overall migration from unused lids to the official fatty food simulant olive oil was determined and compared with the legal limit of 60 mg kg^?1. The results ranged from 76 to 519 mg kg^?1 and as a consequence the products were withdrawn from the market.     

Comparing different gas chromatographic methods for the quantification of bisphenol A (BPA) trace levels in paper and cardboard products from the market

Bisphenol A (BPA; 4,4?-(propane-2,2-diyl)diphenol), a suspected endocrine disruptor with weak estrogenic activity, is used in a variety of consumer products, including paper and cardboard products used as food contact materials. The present study compared four different gas chromatographic methods for the analysis of BPA in paper and cardboard food packages. Eighteen different food packages were extracted and BPA was determined using two different derivatisation reactions – trimethylsilylation with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and halide alkylation with pentafluorobenzoyl chloride (PFBOCl) – and four different separation and detection techniques. The BSTFA derivatives were quantified with (1) GC-MS in single-ion monitoring (SIM) mode with electron ionisation (EI-GC-MS) and (2) GC-MS/MS in multiple reaction monitoring (MRM) mode using electron ionisation (EI-GC-MS/MS); while the PFBOCl derivatives were quantified with (3) GC-MS using electron ionisation (EI-GC-MS) as well as (4) GC-MS with negative chemical ionisation (NCI-GC-MS). All developed methods showed good linearity (R² > 0.9938), precision (CV < 4.5% for reproducibility; CV < 2.2% for repeatability) and sensitivity, with limits of detection (LODs) between 0.02 µg kg^?1 for the pentafluorobenzoyl derivatives measured with the NCI-GC-MS method and 6 µg kg^?1 for the pentafluorobenzoyl derivatives determined with EI-GC-MS. Levels of BPA in the samples were in agreement for all methods, ranging from values below the limit of quantitation (LOQ) to 11.9 mg kg^?1 paper. In a last step, the maximum potential migration into food products was calculated for all tested paper and cardboard samples, assuming a ‘worst case’ scenario of 100% migration.     

Effects of tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1) and its peptic hydrolyzates on spontaneously hypertensive rats

Yam storage protein (YSP) was purified from tubers of Dioscorea alata L. Tainong No. 1 (TN1) to homogeneity by DE‐52 ion‐exchange chromatography. The short‐term (24 h) and long‐term (25 days) antihypertensive effects of YSP‐TN1 and its peptic hydrolyzates (PH‐TN1) were measured in spontaneously hypertensive rats (SHRs). For 24‐h antihypertensive measurements, SHRs (age 10 weeks, body weight from 240 to 250 g) were administered orally once (YSP‐TN1 and PH‐TN1, 40 mg kg^?1 SHR) to measure the mean blood pressure (MBP), systolic blood pressure (SBP) and diastolic blood pressure (DBP). For a long‐term antihypertensive measurement, SHRs (age 12 weeks, body weight from 250 to 270 g) were administered orally once a day for 25 days (YSP‐TN1, 40 mg kg^?1 SHR) to measure SBP, DBP and MBP. Captopril (10 or 15 mg kg^?1 SHR) was used as a positive control. It was found that short‐term administration of 40 mg kg^?1 SHR of YSP‐TN1 and PH‐TN1 effectively lowered SHRs' MBP, SBP and DBP (For YSP‐TN1, the lowest blood pressure was reached in the fourth hour and for PH‐TN1 in the eighth hour). The lasting effects of PH‐TN1 on reduced SHRs' BP were better than those of YSP‐TN1 for one oral administration. For oral administration of 40 mg YSP‐TN1 kg^?1 SHR, the reduced MBP was 21.5 mmHg, which was comparable to 25.2 mmHg (the fourth hour) of 10 mg captopril kg^?1 SHR oral administration. For oral administration of 40 mg PH‐TN1 kg^?1 SHR, the reduced MBP was 33.7 mmHg, comparable to 38.4 mmHg (the fourth hour) of 15 mg captopril kg^?1 SHR. For long‐term 25‐day oral administration of 40 mg YSP‐TN1 kg^?1 SHR once a day, it was found that a feeding trial of YSP‐TN1 effectively lowered SHRs' SBP, DBP and MBP. The greatest reduction in SHRs' blood pressure was reached on the ninth day, for the reduced SBP, 27.7 mmHg; for the reduced DBP, 28.3 mmHg; and for the reduced MBP, 27.5 mmHg. Copyright © 2006 Society of Chemical Industry     

Migration measurement and modelling from poly(ethylene terephthalate) (PET) into soft drinks and fruit juices in comparison with food simulants

Poly(ethylene terephthalate) (PET) bottles are widely used for beverages. Knowledge about the migration of organic compounds from the PET bottle wall into contact media is of interest especially when post-consumer recyclates are introduced into new PET bottles. Using migration theory, the migration of a compound can be calculated if the concentration in the bottle wall is known. On the other hand, for any given specific migration limit or maximum target concentration for organic chemical compounds in the bottled foodstuffs, the maximum allowable concentrations in the polymer C _P,0 can be calculated. Since a food simulant cannot exactly simulate the real migration into the foodstuff or beverages, a worse-case simulation behaviour is the intention. However, if the migration calculation should not be too overestimative, the polymer-specific kinetic parameter for migration modelling, the so-called A _P value, should be established appropriately. One objective of the study was the kinetic determination of the specific migration behaviour of low molecular weight compounds such as solvents with relatively high diffusion rates and, therefore, with high migration potential from the PET bottle wall into food simulants in comparison with real beverages. For this purpose, model contaminants were introduced into the bottle wall during pre-form production. The volatile compounds toluene and chlorobenzene were established at concentrations from about 20–30 mg kg^?1 to 300–350 mg kg^?1. Phenyl cyclohexane was present at concentrations of 35, 262 and 782 mg kg^?1, respectively. The low volatile compounds benzophenone and methyl stearate have bottle wall concentrations of about 100 mg kg^?1 in the low spiking level up to about 1000 mg kg^?1 in the highly spiked test bottle. From these experimental data, the polymer specific parameters (A _P values) from mathematical migration modelling were derived. The experimental determined diffusing coefficients were determined, calculated and compared with literature data and an A _P′ value of 1.0 was derived thereof for non-swelling food simulants like 3% acetic acid, 10% ethanol or iso-octane. For more swelling condition, e.g. 95% ethanol as food simulant, an A _P′ value of 3.1 seems to be suitable for migration calculation. In relation to PET recycling safety aspects, maximum concentrations in the bottle wall were established for migrants/contaminants with different molecular weights, which correspond with a migration limit of 10 μg kg^?1. From the experimental data obtained using food simulants and in comparison with beverages, the most appropriate food simulant for PET packed foods with a sufficient but not too overestimative worse-case character was found to be 50% ethanol. In addition, it can be shown that mass transport from PET is generally controlled by the very low diffusion in the polymer and, as a consequence, partitioning coefficients (K _P/F values) of migrants between the polymer material and the foodstuff do not influence the migration levels significantly. An important consequence is that migration levels from PET food-contact materials are largely independent from the nature of the packed food, which on the other hand simplifies exposure estimations from PET.     

Survey and risk assessment of trace elements in foods from Taiwan containing red mould rice (Monascus) by ICP-MS

The concentrations of seven trace elements (As, Cd, Cr, Pb, Se, Cu and Zn) in 93 red mould rice (Monascus) food samples in Taipei, Taiwan, were determined by inductively coupled plasma-mass spectrometry (ICP-MS) after wet digestion. The results, calculated in mg?kg^?1 (wet weight) for each sample, revealed the general scenario of food safety in Taiwan: As (0.005–12.04), Cd (<0.0005–2.22), Cr (0.014–6.95), Cu (0.012–8.70), Pb (0.001–0.64), Se (<0.001–1.29) and Zn (0.020–67.02). Three food samples were identified with As concentrations higher than regulatory limits: a dietary supplement sample and a seaweed sample with As concentrations that exceeded the limit of Taiwan's health food standard of 2?mg?kg^?1, and a canned eel sample with an As concentration that exceeded the limit of Canada's fish standard of 3.5?mg?kg^?1. This study suggests that the estimated intakes of these seven trace elements from the consumption of foods containing Monascus pose little risk, as the trace element contents in the majority of samples were lower than the permissible/tolerable intakes per week according to the guidelines recommended by the Food and Agricultural Organization/World Health Organization (FAO/WHO). Moreover, their concentrations in foods containing Monascus differ widely for different food varieties, suggesting that external contaminants and raw materials are the main sources of trace elements. This study shows that ICP-MS is a simple method proposed for the determination of As, Cd, Cr, Pb, Se, Cu, and Zn in foods containing Monascus.     

Determination of the caffeine contents of various food items within the Austrian market and validation of a caffeine assessment tool (CAT)

The caffeine content of 124 products, including coffee, coffee-based beverages, energy drinks, tea, colas, yoghurt and chocolate, were determined using RP-HPLC with UV detection after solid-phase extraction. Highest concentrations of caffeine were found for coffee prepared from pads (755?mg?l^?1) and regular filtered coffee (659?mg?l^?1). The total caffeine content of coffee and chocolate-based beverages was between 15?mg?l^?1 in chocolate milk and 448?mg?l^?1 in canned ice coffee. For energy drinks the caffeine content varied in a range from 266 to 340?mg?l^?1. Caffeine concentrations in tea and ice teas were between 13 and 183?mg?l^?1. Coffee-flavoured yoghurts ranged from 33 to 48?mg?kg^?1. The caffeine concentration in chocolate and chocolate bars was between 17?mg?kg^?1 in whole milk chocolate and 551?mg?kg^?1 in a chocolate with coffee filling. A caffeine assessment tool was developed and validated by a 3-day dietary record (r ^2?=?0.817, p?<?0.01) using these analytical data and caffeine saliva concentrations (r ^2?=?0.427, p?<?0.01).     

Survey of the anticoccidial feed additive nicarbazin (as dinitrocarbanilide residues) in poultry and eggs

A survey was carried out on the occurrence of dinitrocarbanilide (DNC), the marker residue for nicarbazin, in poultry produced in Ireland during 2002–2004. Liver (n?=?736) and breast muscle samples (n?=?342) were tested. DNC residues were found in 40 and 26% of liver and breast muscle samples at levels greater than 12.5 and 5?µg?kg^?1, respectively. DNC residues were found at >200?µg?kg^?1 in 12 and 0% of liver and muscle samples, respectively. Samples of breast muscle (n?=?217) imported from 11 countries were also tested for DNC residues. A lower incidence of DNC residues (6%) was found in imported breast muscle. Egg samples (n?=?546) were tested and DNC residues were found in nine samples, with levels ranging between 14 and 122?µg?kg^?1. Analysis of poultry, carried out as part of official food inspection in the period 2004–2006, indicated a reduction in the number of broiler liver samples containing DNC at >200?µg?kg^?1, to approximately 7%. Low levels of DNC residues continue to be found in <2% of egg samples.     

Cadmium content in fresh and canned squid (Loligo opalescens) from the Pacific coastal waters of California (USA)

Cadmium (Cd) levels were determined in 70 samples of mantle tissue and 70 whole individual squid (Loligo opalescens; commercially known as California squid). Samples were collected from the coastal zones of California (USA) during the period 2007/2008. To further investigate consumer exposure to processed fishery products, cadmium concentration was also determined in 200 canned samples of squid. Cd concentrations in raw mantle were low, between 0.01 and 0.29 mg kg^?1 and below the tolerance limit of current regulations (1 mg kg^?1). Respective concentrations in whole individuals were significantly higher, ranging from 0.51 to 1.18 mg kg^?1, attributed to the presence of the visceral portion in whole squid samples. Cd concentrations varied in relation to age and sex of squid, indicating that several physiological factors may influence accumulation. Furthermore, canning of squid substantially enhanced Cd levels. Cd concentration ranged 0.17–0.67 mg kg^?1 in canned mantle tissue and 0.86–2.07 mg kg^?1 in canned whole squid samples, due to both concentration after canning and movement of the metal between different tissues. Several biological compounds, including metallothioneins, nucleic acids and enzymes, may affect Cd concentrations in commercial fishery products.     

Comparative study of the mineral composition of several varieties of potatoes (Solanum tuberosum L.) from different countries cultivated in Canary Islands (Spain)

Potatoes are a basic component of human diets worldwide being an excellent source of minerals linked the maintenance of health. Contents of calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), cupper (Cu), iron (Fe), manganese (Mn), zinc (Zn), nickel (Ni) and chromium (Cr) in seventy‐four fresh potato samples from different varieties consumed in Tenerife Island (Canary Islands, Spain) were determined by flame atomic absorption spetrometry (FAAS). The mean concentrations were 60.1 mg kg^?1, 222 mg kg^?1, 5047 mg kg^?1, 125 mg kg^?1, 1.69 mg kg^?1, 8 mg kg^?1, 1.70 mg kg^?1, 3.88 mg kg^?1, 62.7 μg kg^?1 and 19.9 μg kg^?1 for Ca, Mg, K, Na, Cu, Fe, Mn, Zn, Ni and Cr, respectively. The varieties of local potatoes presented higher mineral contents than imported potatoes. Potassium presented the highest contents in all varieties of potatoes. Iron was the most abundant microelement. Local potatoes offer greater nutritional contributions to the recommended intakes than imported varieties. Within the macrominerals, the highest contribution to the intakes was observed for K, while Fe was the trace element with the largest contribution to the proposed intake.     

Mercury and methylmercury bioaccessibility in swordfish

Concentrations of mercury (Hg) in swordfish (Xiphias gladius) present a food safety problem for many countries. This study analyses total Hg (t-Hg) concentrations in 27 samples of swordfish marketed in Spain in 2005 and in their bioaccessible fractions (soluble concentration in gastrointestinal medium), obtained after applying an in vitro digestion method. Methylmercury (MeHg) was also determined in the bioaccessible fractions. t-Hg concentrations in the samples were 0.41–2.11 mg kg^?1 wet weight, with a mean of 0.96 ± 0.47 mg kg^?1 wet weight. A total of 37% of the samples exceeded the Hg limit set by Spanish legislation (1.0 mg kg^?1 wet weight). Bioaccessible t-Hg concentrations were 0.17–1.72 mg kg^?1 wet weight (0.63 ± 0.4 mg kg^?1 wet weight), corresponding to 38–83% (64% ± 14%) of t-Hg. Bioaccessible MeHg concentrations, representing 94% of the bioaccessible t-Hg concentrations, were 0.16–1.53 mg kg^?1 wet weight, with a mean of 0.49 ± 0.32 mg kg^?1 wet weight. Children and adults who regularly consume this product in Spain have Hg and MeHg intakes that exceed the tolerable daily intake limits recommended by the Food and Agricultural Organization/World Health Organization (FAO/WHO) and US Environmental Protection Agency (USEPA). These results show the need for recommendations about swordfish consumption by population groups at risk in Spain.     

Effects of a glycoconjugate from Lycium barbarum on body composition in growing mice

This study investigated the effect of a kind of glycoconjugate from Lycium barbarum (GLB) on body composition in growing mice. The composition of GLB was determined; the body weight, food conversion rate, visceral index, fat index and mineral concentration in bone and muscle of mice were assessed. The health of the mice was evaluated in a swimming endurance test. The results showed that the contents of neutral sugar, uronic acid, protein and mineral in GLB were (mg g^?1): 287.8, 494.5, 56.3 and 161, respectively. GLB fed at rates of 5 mg kg^?1 d^?1, 10 mg kg^?1 d^?1 and 20 mg kg^?1 d^?1 could reduce the growth rate of body weight, food conversion rate and the subcutaneous fat of mice. The swimming time of the growing mice was increased by GLB treatment. GLB induced an increase in thymus index and a decrease in spleen index. GLB had significant effects on the concentration of Zn and Fe in shank (p < 0.01) and could elevate the concentration of Ca and Zn in haunch muscle. The results showed that GLB was helpful to the development of mice. Copyright © 2006 Society of Chemical Industry     

Elemental composition of commercial sea cucumbers (holothurians)

Toxic and essential elements in 11 different sea cucumber species were determined and compared with daily intake recommendations and maximum allowed levels. The contents of macro-elements contents in dried sea cucumber samples were found to be 25,000–152,000?mg?kg^–1 for Na, 4000–8600?mg?kg^?1 for Mg, 1100–5200?mg?kg^?1 for K, 15,000–68,000?mg?kg^?1 and 36,300–251,000?mg?kg^?1 for Cl. Trace element concentrations in dried sea cucumber samples were found to be 11–100?mg?kg^?1 for Zn, 41–660?mg?kg^?1 for Fe, 3–74?mg?kg^?1 for Cu, 1.1–16?mg?kg^?1 for Mn, 1.4–3.7?mg?kg^?1 for Se, 1.1–9.6?mg?kg^?1 for Cr, and 0.3–5.1?mg?kg^?1 for Ni. All sea cucumber species were rich sources of Na, Cl, Mg, Ca, Fe, Cu, Se and Cr for human consumption. Regarding contaminants, As, Cd and Pb concentrations in dried sea cucumbers were in the ranges of 1.1–6.1, 0.03–0.06 and 0.11–0.69?mg?kg^?1, respectively. Moreover, Hg values of 11 sea cucumbers were below the detection limit (0.01?mg?kg^?1).     

Analytical determination of bisphenol A (BPA) and bisphenol analogues in paper products by LC-MS/MS

ABSTRACT

In this study a sensitive analytical method based on liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous analysis of bisphenol A (BPA), bisphenol AF (BPAF), bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF) and bisphenol S in different paper and board products, including virgin fibre samples and recycled samples. Analytes were extracted from the paper matrix using a simple solvent extraction and chromatographic separation was performed on a C18 core-shell (100 mm x 2.1 mm i.d.; 1.7 µm particle size) column. The developed method showed good linearity (R² > 0.9921) for all analytes. Absolute recoveries ranged from 71 to 115% and precision in terms of reproducibility and repeatability (intra- and inter-day) yielded in relative standard deviations (RSDs) of less than 15.0% and 17.4%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for the different analytes ranged from 0.29 to 0.40 µg kg^?1 paper and from 1.09 to 1.32 µg kg^?1 paper, being in the same range for all analytes. Quantitation of the analytes was performed using the internal standard procedure, with concentrations of < LOQ to 9599 µg kg^?1 for the different analytes. Furthermore, a calculation of the maximum migration, assuming the ‘worst case’ scenario of 100% migration was performed.     

Survey of phthalate levels in Italian oily foods contained in glass jars with PVC gaskets

A method based on gas chromatography/tandem mass spectrometry was used to assess levels of twelve phthalates in 50 samples of oily foods packed in glass jars with metal closure obtained from a retail market. The amounts of di-methyl phthalate, di-ethyl phthalate, di-propyl phthalate, di-butyl phthalate, di-pentyl phthalate, benzyl butyl phthalate, di-cyclohexyl phthalate, di-n-octyl phthalate, di-isononyl phthalate and di-isodecyl phthalate in all samples analysed were less than the limit of quantification (LOQ). Di-(2-ethylhexyl) phthalate was detected in 20 samples in the range from 0.1 to 6 mg kg^?1 with an average of 1.0 mg kg^?1, and it exceeded the specific migration limit (SML) of 1.5 mg kg^?1 in five cases with an average of 3.0 mg kg^?1. Di-isobutyl phthalate was found in four samples at 0.1–0.4 mg kg^?1. The PVC gaskets used for the lids were negative for all tested phthalates, suggesting that the contamination of the foods originated from other sources, e.g. olive oil.     

Evaluation of mercury levels in Pangasius and Cod fillets traded in Sicily (Italy)

Predator fishes at the top of the aquatic food chain can accumulate large concentrations of metals and their consumption, consequently, makes a significant contribution, in particular, to mercury intake. The aim of this study was to determine mercury levels in fillets of two predatory species: pangasius (Pangasius hypophthalmus) from the Vietnam region of Megong and Chao Pharayai and cod (Gadus morhua) from the Baltic and North Sea, both being commercially important in the Italian market. A comparative analysis of these two imported fish species was carried out as a risk assessment for consumer safety. The results showed the presence of higher mercury levels in pangasius (0.41?±?0.08?mg?kg^?1) than in cod (0.11?±?0.004?mg?kg^?1) fillets. These data underline the importance of monitoring on imported fish before marketing, to evaluate better the risk of mercury exposure through fish and seafood consumption, and of selecting safer fishes for consumption by those groups more sensitive to the toxic effects of this metal.     

Analysis of isothiazolinone biocides in paper for food packaging by ultra-high-performance liquid chromatography–tandem mass spectrometry

A novel and simple method to detect isothiazolinone-type biocides (2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BIT) and 2-octyl-3-isothiazolinone (OIT)) in paper used for food packaging by ultrasonic extraction coupled with UPLC-MS/MS was developed. Parameters affecting process efficiency such as extraction solvents, UPLC mobile phase, gradient elution procedure and MS/MS conditions were studied to optimise the operating conditions. Using the optimised gradient elution procedure, the retention time was less than 6?min. The limits of detection (LODs) were found to be between 0.001 and 0.010?mg?kg^?1, which was validated using actual concentrations. After diluting the standard solution with a blank matrix, the linear calibration curve ranges were 0.002–1.000?mg?kg^?1 for BIT and OIT, 0.005–1.000?mg?kg^?1 for MI, and 0.020–1.000?mg?kg^?1 for CMI, with correlation coefficients higher than 0.9985 (n?=?6). A good level of precision with a mean recovery greater than 81.3% and a relative standard deviation (RSD) less than 6.2% were also obtained. A methodology has been proposed for the analysis of isothiazolinones in paper.     

Organochlorine pesticide residues in domestic fowl (Gallus domesticus) eggs from central Kenya

In 367 domestic fowl (Gallus domesticus) eggs collected from 61 farms, residues of 10 pesticides were detected in various combinations and in the following order of frequency: p,p′-DDE (in 100% of the eggs), p,p′-DDT (98%), dieldrin (95%), Indiane (66%), p,p′-DDD (46%), o,p′-DDT (17%), β-HCH (9%), γ-HCH (5%), endrin (4%) and aldrin (0–5%). No residues of heptachlor, heptachlor epoxide, HCB or PCBs were found. The mean concentration (0–70 mg kg^?1 eggs; range <0–01–10–25) of total DDT exceeded the extraneous residue limit (ERL) of 0–50 mg kg^?1. The mean dieldrin residue level (0–35 mg kg^?1; range 0–01–14–90) was 3–5 times higher than the ERL (0–10 mg kg^?1). Only 3% of the eggs exceeded the ERL for Indane. The 156 eggs from free-range hens had significantly (P<0–05) higher residue concentrations of total DDT, dieldrin and Iindane than eggs collected from hens kept in enclosures. The mean ratio [p,p′-DDT]/[p,p′-DDE] in eggs from enclosed hens (0–97) was significantly higher (P<0–01) than in eggs from free-range hens (0–53), indicating that the former had a more direct exposure to p,p′-DDT, whereas the latter obtained more of it after environmental conversion to p,p′-DDE. Eggs from a rice-growing area had the highest concentrations of all pesticide residues detected. Accumulation ratios indicated that the levels of DDT and Iindane in the feed of enclosed hens could account for the levels in the corresponding eggs. The much higher accumulation ratios calculated for the free-range hens demonstrated that the feed ingested by these chickens obviously contained ingredients additional to those sampled, and revealed probable extensive environmental contamination by these persistent pesticides. The present results indicate that there is a need to identify sources of dieldrin in the eggs of domestic fowls and, where necessary to investigate local wildlife samples. The amounts of total DDT and dieldrin in eggs in this study seem to be higher than reported from any other country. Toxicological evaluation of the results indicates that, at lest in parts of KEnya there is a need for improved practices in the use of some organochlorine pesticides.     

Novel approach to fast determination of multiple pesticide residues using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)

A rapid, high-throughput method employing ultra-performance liquid chromatography with tandem quadrupole mass spectrometry (UPLC-MS/MS) was developed and optimized for simultaneous quantification and confirmation of 64 pesticide residues and their toxic metabolites in fruit extracts prepared by a buffered QuEChERS procedure. The total time required for UPLC-MS/MS analysis was 8 min plus 2 min for re-equilibration to the initial UPLC conditions. Performance characteristics were determined for apple extracts spiked at 10 µg kg^?1. The repeatability of measurements expressed as relative standard deviations was in the range 1.5–13% at this level for most analytes. Thanks to very low limits of quantification (<10 µg kg^?1for the majority of pesticides), an optimized method allows for the reliable control of not only common maximum residue limits (MRLs) set by European Union regulation for various pesticides/fruit combinations, but also of a uniform MRL of 10 µg kg^?1endorsed for baby food.     

Toxic (Pb,Cd, Hg) and essential (Fe,Cu, Zn,Mn) metal content of liver tissue of some domestic and bush animals in Ghana

Accumulation of toxic metals in liver, a rich natural source of essential elements, can present health risks to regular consumers of liver. A total of 35 fresh liver samples of cow, sheep, goat, pig, grass-cutter (Thryonomys swinderianus), gaint rat (Cricetomys gambianus), red deer (Cervus elaphus), chicken and antelope (Antilocapra americana) were obtained from three different markets in Accra and Kumasi, Ghana. Samples were analyzed using atomic absorption spectrometry and an automatic mercury analyzer. Levels of iron in the grass-cutter and pig of 500.5–645.4 mg kg^?1 were the highest in the animal livers examined. Mn concentrations were highest in grass-cutter and rat liver, ranging 16.5–30.2 mg kg^?1. The safe Cu and Zn permissible limits of 20 and 50 mg kg^?1 were exceeded in 70 and 75% of the liver samples, respectively. Generally, for each animal group studied, at least 50% of the sample livers exceeded the Cd permissible limit of 0.5 mg kg^?1. The levels of Pb, which ranged 1.3–13.8 mg kg^?1, exceeded the proposed European Commission (EC) limit of 0.5 mg kg^?1. Care must be taken by regular consumers of the iron-rich animal livers of grass-cutter, pig and rat because they also had the highest levels of Pb (in grass-cutter and pig) and Cd (in grass-cutter, rat and pig). The liver samples analyzed for Hg had values far below the permissible limit of 0.5 mg kg^?1.