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Food additives contaminants [journal]
- Implementation of the Bacillus cereus microbiological plate used for screening of tetracyclines in raw milk samples with STAR protocol - problem with false negative results solved. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 18.
In antibiotic residue analyses the first step of screening is just as important as the following steps. Screening methods need to be quick and inexpensive, but above all sensitive enough to detect the antibiotic residue at or below the maximum residue limit (MRL). In the case of a positive result the next step is conducted and further methods are used for confirmation. MRLs stated in the EU Regulation 37/2010 for tetracyclines in raw milk are: 100 µg/kg for tetracycline, 100 µg/kg for oxytetracycline, 100 µg/kg for chlortetracycline and no limit for doxycycline because it is prohibited to use in animals from which milk is produced for human consumption. The current five-plate microbiological screening method for the detection of antibiotic residues in raw milk was found simple and inexpensive, but not specific, sensitive and reliable enough to detect tetracycline at MRL in routine raw milk screening procedures. Spiking samples with tetracycline at the MRL level and applying them on Bacillus cereus ATCC 11778 microbiological plates often gave false negative results, indicating that tetracyclines may have to be inactivated or masked. Tetracyclines seem to bind to a certain component in milk. Consequently, when applying samples to the B. cereus microbiological plate the antibiotic is not able to inhibit the growth of B. cereus what disables the formation of inhibition zones on the test plate. After adding the appropriate amount of citric acid into the milk samples we solved the problem of false negative results. During the validation 79 samples of milk were spiked with tetracyclines at different concentrations: 100 µg/kg for tetracycline, 100 µg/kg for oxytetracycline, 80 µg/kg for chlortetracycline and 30 µg/kg for doxycycline. Concentrations used in the validation matched the requirements for MRLs (they were either at or below the MRLs) stated in the EU Regulation 37/2010. The sensitivity of the validation was 100%.
- An immunogen synthesis strategy for the development of specific anti-deoxynivalenol monoclonal antibodies. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 18.:1-9.
An immunogen synthesis strategy was designed to develop anti-deoxynivalenol (DON) monoclonal antibodies with low cross-reactivity against structurally similar trichothecenes. A total of eight different DON immunogens were synthesised, differing in the type and position of the linker on the DON molecule. After immunisation, antisera from mice immunised with different DON immunogens were checked for the presence of relevant antibodies. Then, both homologous and heterologous enzyme-linked immunosorbent assays (ELISAs) were performed for hybridoma screening. Finally, three monoclonal antibodies against DON and its analogues were generated. In addition, monoclonal antibody 13H1 could recognise DON and its analogues in the order of HT-2 toxin > 15-acetyldeoxynivalenol (15-ADON) > DON, with IC50 ranging from 1.14 to 2.13 µg ml(-1). Another monoclonal antibody 10H10 manifested relatively close sensitivities to DON, 3-acetyldeoxynivalenol (3-ADON) and 15-ADON, with IC50 values of 22, 15 and 34 ng ml(-1), respectively. Using an indirect ELISA format decreases the 10H10 sensitivity to 15-ADON with 92%. A third monoclonal antibody 2A9 showed to be very specific and sensitive to 3-ADON, with IC50 of 0.38 ng ml(-1). Using both 2A9 and 10H10 monoclonal antibodies allows determining sole DON contamination.
- A method for the determination of cadmium, lead, nickel, cobalt and copper in seafood after dispersive liquid-liquid microextraction. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 16.
In this work, we developed a method using dispersive liquid-liquid microextraction (DLLME) and detection by inductively coupled plasma optical emission spectroscopy (ICP-OES) for the determination of trace elements in seafood samples. The procedure allowed the simultaneous determination of Cd (II), Pb (II), Ni (II) Cu (II) and Co (II) after pre-concentration using sodium diethyldithiocarbamate (DDTC) as a chelating agent. Under optimized conditions, the method had a limit of detection (LOD) of 0.03, 0.11, 0.12, 0.18 and 0.12 µg L(-1) for Cd (II), Pb (II), Ni (II) Cu (II) and Co (II), respectively. The following enrichment factors were obtained: 16 (Cd), 34 (Pb), 20 (Ni) 34 (Cu) and 12 (Co). The procedure was applied to the determination of these elements in seafood (shrimp, mussel, bass and mullet) samples. The method is simple, efficient and easy-to-perform for the simultaneous determination of elements in seafood samples by ICP-OES.
- Determination of pyrrolizidine alkaloids in tea, herbal drugs and honey. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 15.
Honey was previously considered to be one of the main food sources of human pyrrolizidine alkaloid (PA) exposure in Europe. However, comprehensive analyses of honey and tea sampled in the Berlin retail market revealed unexpected high PA amounts in teas. Our study comprised the analysis of 87 honey as well as 274 tea samples including black, green, rooibos, melissa, peppermint, chamomile, fennel, nettle and mixed herbal tea or fruit tea. Total PA concentrations in tea ranged from <LOD to 5647 µg kg(-1), while a mean value of about 10 µg kg(-1) was found in honey samples. Additionally, herbal drugs were investigated to identify the source of PA in teas. Results suggest that PA in tea samples are most likely a contamination caused by co-harvesting of PA producing plants. In some cases such as fennel, anise or melissa it cannot be excluded that these plants are able to produce PA themselves.
- Health risk assessment of Chinese consumers to nickel via dietary intake of foodstuffs. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 12.
In this study, a quantitative risk assessment was carried out to characterize the health risk from nickel (Ni) via dietary exposure for Chinese consumers. Ni contamination in foods was investigated by conducting a survey and a literature review. The daily diet of the public was categorized into nine food groups and the consumption data for each group were obtained from a nationwide survey. Deterministic and probabilistic methods were applied to calculate the target hazard quotients (THQs) by comparing the estimated dietary Ni intake with respect to the tolerable daily intake (TDI). The average estimated daily Ni intake (μg/kg bw/day) for males, females, 2-3 years old children and 4-17 years old children were 7.2, 7.3, 17.1 and 10.0, respectively. The consumption of cereals, beans, vegetables and marine products contributed significantly to the total daily intake of Ni. The mean THQ values (95% confidence interval) and the probability of dietary nickel exposure higher than the TDI were 0.60 (0.58-0.62) and 8.2% for males, 0.61 (0.59-0.63) and 8.4% for females, 1.35 (1.32-1.39) and 72.0% for 2-3 years old children, and 0.87 (0.82-0.91) and 28.5% for 4-17 years old children, respectively. This study showed a potential health risk from Ni via dietary exposure for Chinese consumers, especially among children.
- Impact of wine manufacturing practice on the occurrence of fining agents with allergenic potential. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 10.
Proteinogenic wine fining agents are hidden allergens and could present a risk for consumers with allergies. Therefore the European Parliament adopted Directive 2003/89/EC amending Directive 2000/13/EC to declare ingredients, contaminations and processing aids that are known to trigger allergic reactions. The Amendment Regulation (EU) 1266/2010 excluded the labeling of wines which are processed with hen´s egg and products thereof until June 30th, 2012 to get more scientific findings. After July 1st 2012 wine fining agents have to be declared if above 0.25 mg/L (Regulation (EU) 579/2012 in conjunction to article 120 g of Regulation (EU) 1234/2007). The OIV (Organisation International de la Vigne et du Vin) advises this limit of detection for potential allergenic residues of proteins. Wine fining agents are processing aids and according to the wine producer's knowledge will be removed after coagulation by filtration or other production steps. Due to lack of scientific data residues of fining agents in the final product could not be excluded. In this risk assessment, highly sensitive ELISA methods for ovalbumin of known origin for wine have been developed. The objective was to investigate the presence of allergen residues in wine after certain technological treatments were applied to remove the wine fining agents. For all developed ELISA methods the LODs are in the low µg/L range between 5 and 10 µg/L fining agent whereas the LOQ varies between 5 and 80 µg/L fining agent. The results of investigation of well-known wines and fining agents demonstrate that white wines fined with white or ovalbumin from hen's egg could retain allergens. The use of certain technological procedures during wine processing leads to different results. In white wine, bentonite or sheet filtration followed by sterile filtration lead to wines containing no detectable amounts of ovalbumin. In red wine, especially the final sterile filtration removes the fining agents.
- Determination of chloramphenicol residues in commercial chicken eggs in the Federal Capital Territory, Abuja, Nigeria. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 10.
The use of antibiotics in poultry can result in residues in eggs. The joint FAO/WHO committee recommended banning the use of chloramphenicol (CAP) in food animals due to its public health hazards of aplastic anemia, leukemia, allergy, antibacterial-resistance and carcinogenicity. In this paper we determined the prevalence of CAP residues in chicken eggs and assessed the usage and awareness of its ban amongst poultry farmers in the Federal Capital Territory (FCT), Abuja, Nigeria. A cross-sectional survey of registered poultry farmers in FCT was conducted using questionnaires to determine CAP administration in poultry and awareness of its ban. Pooled egg samples were collected from each poultry farm surveyed and from randomly sampled government-owned markets in FCT. Source of eggs by state were identified by the marketer at time of collection. Samples were analyzed using an Enzyme-Linked Immunosorbent Assay (ELISA) technique for the presence of CAP, and prevalence was determined. Out of 288 total pooled samples collected, 257 (89.2%) were from the markets and 31 (10.8%) were from poultry farms. A total of 20 (7%) pooled egg samples tested CAP-positive; Market eggs originated from 15 (41%) states of the country. Of the market eggs, 16 (6.2%) pooled samples tested positive. Of eggs from poultry farms, 4 (12.9%) tested positive. Mean CAP concentrations in the positive samples ranged from 0.49 to 1.17 µg kg(-1) (parts per billion). CAP-use amongst poultry farmers in FCT was 75.5%; awareness of the CAP ban was 26.3%. Though 66% of veterinarians were unaware of a CAP-ban, they were more likely to be aware than other poultry farmers (odds ratio [OR] = 1.4). Farm managers that use CAP were more likely to be aware of CAP-ban than the farm managers not using CAP (OR = 5.5;P = 0.04). Establishing Drug Residue Surveillance and Control Program and enforcement of CAP legislation/regulation is needful to educate and prohibit the widespread CAP-use amongst Nigerian poultry farmers.
- A simple and reliable liquid chromatography-tandem mass spectrometry method for the determination of aflatoxin B1 in feed. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 18.:1-8.
A chromatographic method is proposed for the analysis of aflatoxin B1 in cereal-based feed, particularly targeted to dairy animals. The method is based on a solid-liquid extraction followed by a Mycosep 226 clean-up. Accuracy and precision were established at the LOQ (1 µg kg(-1)) with a spiked sample as well as with two other different naturally contaminated reference materials. The mean overall recovery (n = 18) was 100.8%, with a confidence interval of 2.7% and a CV% of 5.5%. The performance of the proposed method was compared with the AOAC method based on the use of immunoaffinity chromatography columns, proving that it could be considered a valid alternative. Moreover, the sample preparation is very simple and straightforward, potentially being applicable as a high-throughput method. On account of its simplicity and low cost, the method may be applied to the analysis of a large number of samples in the occasion of outbreaks of large-scale contamination.
- Statistical method to assess usual dietary intakes in the European population. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 10.:1-13.
Food consumption data are a key element of EFSA's risk assessment activities, forming the basis of dietary exposure assessment at the European level. In 2011, EFSA released the Comprehensive European Food Consumption Database, gathering consumption data from 34 national surveys representing 66,492 individuals from 22 European Union member states. Due to the different methodologies used, national survey data cannot be combined to generate European estimates of dietary exposure. This study was executed to assess how existing consumption data and the representativeness of dietary exposure and risk estimates at the European Union level can be improved by developing a 'Compiled European Food Consumption Database'. To create the database, the usual intake distributions of 589 food items representing the total diet were estimated for 36 clusters composed of subjects belonging to the same age class, gender and having a similar diet. An adapted form of the National Cancer Institute (NCI) method was used for this, with a number of important modifications. Season, body weight and whether or not the food was consumed at the weekend were used to predict the probability of consumption. A gamma distribution was found to be more suitable for modelling the distribution of food amounts in the different food groups instead of a normal distribution. These distributions were combined with food correlation matrices according to the Iman-Conover method in order to simulate 28 days of consumption for 40,000 simulated individuals. The simulated data were validated by comparing the consumption statistics of the simulated individuals and food groups with the same statistics estimated from the Comprehensive Database. The opportunities and limitations of using the simulated database for exposure assessments are described.
- Multi-commutated fluorometric optosensor for the determination of citrinin in rice and red yeast rice supplements. [JOURNAL ARTICLE]
- Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014 Sep 9.:1-7.
Citrinin is a toxic secondary metabolite first isolated from Penicillium citrinum, although is also produced by other species of Penicillium and Aspergillus. It has highly toxic, mutagenic, teratogenic and carcinogenic properties and is often found in crops, vegetables and fruit. To our knowledge there is no specific legislation on maximum levels permitted for citrinin, so no official analytical method is currently available for its determination. Our laboratory developed a fluorometric flow-through optosensor using Sephadex SPC-25 as solid support. Multi-commutated flow injection analysis was used for the construction of the manifold and for handling solutions. In this way, we minimised waste generation and human intervention, which are critical aspects when dealing with highly toxic compounds such as citrinin. The optimum excitation/emission wavelengths were set at 330/494 nm; the calibration curve was linear in the concentration range 35-900 ng ml(-1). A detection limit of 10.5 ng ml(-1) and relative standard deviations (RSDs) lower than 3% were obtained. The developed optosensor was applied to the determination of citrinin in rice and dietary supplements containing red yeast rice.