Food additives and contaminants最新文献

A new method for the determination of pentachlorophenol (PCP) in different foods was developed using capillary gas chromatography (GC) and microwave induced-plasma atomic emission spectrometry (MIP-AED). The analyte is first derivatized and then extracted and pre-concentrated by solid-phase microextraction (SPME) in headspace (HS) mode. A clear matrix effect was found for the different samples investigated, so that standard addition was required for quantification. Detection limits of 0.03-6.0 ng g(-1) were obtained, depending on the sample analysed. The method gave recoveries of 81-109% from spiked samples. Concentration levels of PCP ranged from 0.3 to 1.5 ng g(-1) were found in honey, but no PCP was detected in other samples.

A survey was carried out to assess the levels of 20 organochlorine and 15 organophosphate pesticides in wheat grown in two regions of the Vojvodina Province in Serbia. A total of 49 samples of seven wheat varieties were collected during the 2004 harvest. In addition, a composite sample of cultivated wheat varieties was prepared from 36 samples coming from the same regions harvested in 2003 for comparison. Official method of analysis AOAC 970.52 was applied for the determination of pesticide residues. The ranges of mean values for organochlorine residues were 32-47 ng g(-1) for beta-HCH; 28-41 ng g(-1) for gamma-HCH; <1-61 ng g(-1) for aldrin; 5-132 ng g(-1) for dieldrin; 15-111 ng g(-1) for endrin ketone; and <1-77 ng g(-1) for endrin aldehyde. For organophosphate residues the ranges were: 7-27 ng g(-1) for thionazin; <5-35 ng g(-1) for disulphoton; 42-79 ng g(-1) for parathion methyl; 422-1336 ng g(-1) for chlorpyriphos; and <5-281 ng g(-1) for parathion. The mean levels of residues were compared with the regulated maximum levels according to the European Commission and Serbian national regulation, and the average intake of residues from wheat-based products was estimated for the Serbian population.

A sample preparation procedure for the determination of deoxynivalenol (DON) using attenuated total reflection mid-infrared spectroscopy is presented. Repeatable spectra were obtained from samples featuring a narrow particle size distribution. Samples were ground with a centrifugal mill and analysed with an analytical sieve shaker. Particle sizes of <100, 100-250, 250-500, 500-710 and 710-1000 microm were obtained. Repeatability, classification and quantification abilities for DON were compared with non-sieved samples. The 100-250 microm fraction showed the best repeatability. The relative standard deviation of spectral measurements improved from 20 to 4.4% and 100% of sieved samples were correctly classified compared with 79% of non-sieved samples. The DON level in analysed fractions was a good estimate of overall toxin content.

A selective and sensitive procedure has been developed and validated for the determination of acrylamide in difficult matrices, such as coffee and chocolate. The proposed method includes pressurised fluid extraction (PFE) with acetonitrile, florisil clean-up purification inside the PFE extraction cell and detection by liquid chromatography (LC) coupled to atmospheric pressure ionisation in positive mode tandem mass spectrometry (APCI-MS-MS). Comparison of ionisation sources (atmospheric pressure chemical ionisation (APCI), atmospheric pressure photoionization (APPI) and the combined APCI/APPI) and clean-up procedures were carried out to improve the analytical signal. The main parameters affecting the performance of the different ionisation sources were previously optimised using statistical design of experiments (DOE). PFE parameters were also optimised by DOE. For quantitation, an isotope dilution approach was used. The limit of quantification (LOQ) of the method was 1 microg kg(-1) for coffee and 0.6 microg kg(-1) for chocolate. Recoveries ranged between 81-105% in coffee and 87-102% in chocolate. The accuracy was evaluated using a coffee reference test material FAPAS T3008. Using the optimised method, 20 coffee and 15 chocolate samples collected from Valencian (Spain) supermarkets, were investigated for acrylamide, yielding median levels of 146 microg kg(-1) in coffee and 102 microg kg(-1) in chocolate.

The presence of the anabolic steroid boldenone in animals has become a research topic as its occurrence is proposed to be a marker for illegal hormone administration. However, boldenone can also be formed from beta-sitosterol, a phytosterol present in animal feed, as well as from endogenous sources. The observations in animals together with the increased consumption of phytosterol-enriched foods in the Western population led the authors to the hypothesis that consumption of phytosterol-enriched foods might possibly lead to increased boldenone levels in humans. The authors performed a pilot study among female volunteers (n = 10) to investigate whether boldenone concentrations in urine were detectable after consumption of 25 g day(-1) of phytosterol-enriched margarines for 1 week. Urine samples were collected at days 0, 3 or 4, and 7. Urine of a sitosterolemia (a rare autosomal recessively inherited lipid metabolic disorder) patient was collected as a positive control case. No traces of boldenone were detected in either the volunteers or in the patient. In conclusion, there is no evidence of formation of boldenone in women after consumption of the recommended amount of phytosterol-enriched margarines.

A semi-automatic method for the determination of polycyclic aromatic hydrocarbons (PAHs) in edible oils using a combined gel permeation chromatography/solid-phase extraction (GPC/SPE) clean-up is presented. The method takes advantage of automatic injections using a Gilson ASPEC XL sample handling system equipped with a GPC column (S-X3) and pre-packed silica SPE columns for the subsequent clean-up and finally gas chromatography-mass spectrometry (GC-MS) determination. The method was validated for the determination of PAHs in vegetable oils and it can meet the criteria for the official control of benzo[a]pyrene levels in foods laid down by the Commission of the European Communities. A survey of 69 vegetable oils sampled from the Danish market included olive oil as well as other vegetable oils such as rapeseed oil, sunflower oil, grape seed oil and sesame oil. Levels of benzo[a]pyrene in all the oils were low (<0.2-0.8 microg kg(-1)), except for one sample of sunflower oil containing 11 microg kg(-1) benzo[a]pyrene.

Environmental contaminants originate from diverse sources and, owing to their ubiquitous presence in the environment, may appear in foods. Setting standards in food is increasingly important within the European Union and world-wide to protect consumers' health and to avoid trade barriers. This paper analyses how maximum levels for environmental contaminants in food were derived by the Codex Alimentarius Commission, by the European Union and by national authorities (USA, Germany). Both the risk assessment process (derivation of tolerable intake values and intake assessment by scientific bodies) and the risk management process (derivation of maximum levels by risk management bodies) are discussed. The various organizations show similar approaches and similar numerical values for maximum levels of the same contaminants in the same food items. In the area of decision-making for risk management, there was a noticeable lack of transparency in all the investigated systems. Recommendations are made for the development and harmonization of exposure assessment and communications between risk assessment and risk management processes, for improvements in documentation and for greater transparency within risk management decision-making processes.

The aim of this study was to determine the prevalence of Clostridium perfringens and its toxins in minced meat. A total of 96 minced meat samples were collected from local markets (16) and small butcher's shops (80) in Kars (Turkey). Samples were analysed for the presence of C. perfringens and its toxins using a commercially available ELISA kit. A total of 31 (32%) Clostridium spp. strains were isolated and 17 (55%) of these isolates were identified as C. perfringens. Four (25%) of the samples from local markets and 27 (34%) from small butcher's shops were contaminated with Clostridium spp. Furthermore, C. perfringens was isolated from two (12%) and 15 (19%) samples from local markets and small butcher's shops, respectively. Mean counts of Clostridium spp. were 2.2 +/- 0.83 x 10(2) CFU g(-1) for local markets and 4.35 +/- 8.53 x 10(2) CFU g(-1) for small butcher's shops; mean counts for C. porringers were 2.75 +/- 0.21 x 10(2) and 6.82 +/- 10.96 x 10(2) CFU g(-1) from markets and butcher's shops, respectively. The number of samples contaminated with both Clostridium spp. and C. perfringens was higher in small butcher's shops than in local markets. Moreover, higher numbers of Clostridium spp. and C. perfringens were isolated in samples from small butcher's shops than from local markets. A total of 13 (13%) samples were also positive for toxins produced by the organism, as detected by ELISA. Eleven samples from small butcher's shops and two samples from local markets were positive for the C. perfringens toxins tested. Moreover, two (12%), one (1%), four (4%) and two (2%) samples were contaminated with C. perfringens types A, B, C and D, respectively. In conclusion, some meat samples collected from local markets and small butcher's shops contained C. perfringens and its toxins and, therefore, present a potential risk of food poisoning.

The Allium cepa assay is an efficient test for chemical screening and in situ monitoring for genotoxicity of environmental contaminants. The test has been used widely to study genotoxicity of many pesticides revealing that these compounds can induce chromosomal aberrations in root meristems of A. cepa. Pesticide residues can be present in fruit and vegetables and represent a risk for human health. The mutagenic and carcinogenic action of herbicides, insecticides and fungicides on experimental animals is well known. Several studies have shown that chronic exposure to low levels of pesticides can cause birth defects and that prenatal exposure is associated with carcinogenicity. This study evaluated the potential application of plant genotoxicity tests for monitoring mutagens in edible vegetables. The presence of pesticides and genotoxic compounds extracted from 21 treated vegetables and eight types of grapes sampled from several markets in Campania, a region in Southern Italy, was monitored concurrently. The extracts were analysed for pesticides by gas chromatography and high-performance liquid chromatography, and for genotoxicity using two plant tests: the micronucleus test and the chromosomal aberration test in A. cepa roots. Thirty-three pesticides were detected, some of which are not approved. Genotoxicity was found in some of the vegetables and grapes tested. Allium cepa tests proved to be sensitive in monitoring genotoxicity in food extracts. The micronucleus test in interphase cells gave a much higher mutagenicity than the chromosomal aberration test in anaphase-telophase cells.

The fumonisins are mycotoxins produced mainly by Fusarium verticillioides and F. proliferatum in maize, the predominant cereal staple for subsistence farming communities in southern Africa. In order to assess exposure to these mycotoxins in the Bizana (now known as Mbizana) and Centane magisterial areas of the former Transkei region of the Eastern Cape Province of South Africa, the actual maize consumption by different age groups in these communities was measured. In the groups 1-9 years (n = 215) and 10-17 (n = 240) years, mean consumption (+/-standard error) was 246 +/- 10.8 and 368 +/- 10.3 g per person day(-1), respectively, with no significant difference (p > 0.05) between the magisterial areas. For adults (18-65 years) mean maize consumption in Bizana (n = 229) and Centane (n = 178) were significantly different (p < 0.05) at 379 +/- 10.5 and 456 +/- 11.9 g per person day(-1), respectively. An exposure assessment was performed by combining the maize consumption distribution with previously determined levels of total fumonisin (fumonisins B(1) and B(2) combined) contamination in home-grown maize in these two areas. Assuming an individual adult body weight of 60 kg, fumonisin exposure in Bizana, an area of relatively low oesophageal cancer incidence, was 3.43 +/- 0.15 microg kg(-1) body weight day(-1), which was significantly lower (p < 0.05) than that in Centane (8.67 +/- 0.18 microg kg(-1) body weight day(-1)), an area of high oesophageal cancer incidence. Mean fumonisin exposures in all age groups in both Bizana and Centane were above the provisional maximum tolerable daily intake (PMTDI) of 2 microg kg(-1) body weight day(-1) set by the Joint FAO/WHO Expert Committee on Food Additives.