Feed additives diclazuril and nicarbazin in egg and liver samples from Croatian farms

In total 307 egg and 275 liver samples were examined for nicarbazin and 365 eggs for diclazuril over a 30-month period. Enzyme-linked immunosorbent assay methods used for quantification were validated according to European Commission Decision 2002/657/EC. Non-compliant samples were confirmed by LC-MS/MS. Mean diclazuril concentrations in egg samples were 0.31?µg?kg^?1, which is below the MRL. In only one egg sample, 2.26?µg?kg^?1 was determined by enzyme-linked immunosorbent assay, although confirmation by LC-MS/MS gave a value of 1.6?µg?kg^?1. Mean nicarbazin levels determined were 1.85?µg?kg^?1 in egg and 21.1?µg?kg^?1 in liver samples. Four samples, one egg and three livers, yielded elevated concentrations of nicarbazin, but only in the egg sample the LC-MS/MS method confirmed nicarbazin (106?µg?kg^?1) above the MRL value.     

Development of an on-line molecularly imprinted chemiluminescence sensor for determination of trace olaquindox in chick feeds

BACKGROUND: Olaquindox, as one of the antimicrobial growth accelerants, is usually used in livestock production to improve feed efficiency. Due to health concerns over possible carcinogenic, mutagenic and photoallergenic effects of olaquindox on animals, the development of simple, rapid and sensitive analytical method for determination of olaquindox is crucial and necessary. RESULTS: In this study, a surface molecularly imprinted polymer was prepared by a molecular imprinting technique in combination with a sol‐gel process using activated silica gel as a support material. This imprinted material exhibited with good recognition and selective ability, and fast adsorption‐desorption dynamics toward olaquindox. Using it as the recognition element, a new on‐line molecularly imprinted solid phase extraction coupled with chemiluminescence sensor for the determination of olaquindox was developed. The factors affecting preconcentration of the analytes and sensitivity of the method were all investigated. Under the optimal condition, the linear range of the calibration graph was between 2 × 10^?8 and 1 × 10^?6 g mL^?1, and the detection limit of this method was 7 × 10^?9 g mL^?1. The blank chick feed samples spiked with olaquindox at 0.3, 0.9 and 1.5 µg g^?1 levels were extracted and determined by this presented method with recoveries ranging from 87% to 94%. This method was validated by high‐performance liquid chromatography and the results correlated well with those obtained by both methods. Moreover, this method was quantitatively analysed with two contaminated chick feed samples. CONCLUSION: This study will provide a sensitive and fast method for the monitoring of olaquindox residues in foods. Copyright © 2012 Society of Chemical Industry     

Development and validation of an indirect competitive enzyme-linked immunosorbent assay for monitoring quinoxaline-2-carboxylic acid in the edible tissues of animals

The feed drug additive carbadox is a suspected carcinogen and mutagen. To monitor effectively residues of carbadox in the edible tissues of food-producing animals, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to detect quinoxaline-2-carboxylic acid, the marker residue of carbadox, was developed. Several haptens were synthesised and conjugated to the carrier protein. Nine female New Zealand white rabbits were immunised with the immunising conjugates to produce polyclonal antibodies according to the designed schemes of immunisation. The highly specific antibody that was very sensitive to N-butylquinoxaline-2-carboxamide with an IC₅₀ value of 7.75?µg?l^?1 was selected for the development of an ic-ELISA. The standard curves based on the N-butylquinoxaline-2-carboxamide matrix calibration ranged from 0.2 to 51.2?µg?l^?1. The decision limit and detection capability of the ic-ELISA were 0.60 and 0.83?µg?kg^?1 for liver and 0.68 and 0.79?µg?kg^?1 for muscle of swine, respectively. The recoveries were 57–108% with coefficients of variation of less than 20% when the quinoxaline-2-carboxylic acid was spiked into liver and muscle with the concentrations of 1.0–20.0?µg?kg^?1. Excellent correlations between the results of the ic-ELISA and an HPLC method (r?=?0.9956???0.9969) were observed for incurred tissues. These results suggest that the ic-ELISA is a sensitive, accurate and low-cost method that would be a useful tool for screening residues of carbadox in the edible tissues of food-producing animals.     

Immunoassay based on monoclonal antibodies versus LC-MS: deoxynivalenol in wheat and flour in Southern Brazil

An indirect competitive enzyme-linked immunosorbent assay (ELISA) method using a monoclonal antibody for deoxynivalenol (DON) detection in wheat and flour was standardised and validated (detection limit?=?177.1?µg?kg^?1) and its performance was compared with LC-MS, quantification limit?=140?µg?kg^?1). DON recovery ranged from 88.7% to 122.6% for wheat grain and from 70.6% to 139.3% for flour. Among the 38 wheat samples evaluated, DON was detected in 29 samples (76.3%) by ic-ELISA (281.6–12?291.4?µg?kg^?1) and in 22 samples (57.9%) by LC-MS (155.3–9906.9?µg?kg^?1). The 0.93 correlation coefficient between ic-ELISA and LC-MS data in 19 positive DON wheat samples demonstrated the reliability and efficiency of ic-ELISA. Results indicated that standardised ic-ELISA was suitable for DON screening in wheat samples and the need for continuous monitoring of mycotoxin levels in foodstuffs.     

Molecularly imprinted solid-phase extraction combined with high-performance liquid chromatography for analysis of trace olaquindox residues in chick feeds

BACKGROUND: Olaquindox, one of the antimicrobial growth accelerants, is usually used as a feed additive in livestock production to improve feed efficiency. Due to health concerns over possible carcinogenic, mutagenic and photoallergenic effects of olaquindox on animals, the development of a simple, rapid and sensitive analytical method for determination of olaquindox is crucial and necessary. RESULTS: In this paper, a novel and hydrophilic functionalised material of olaquindox‐imprinted polymer was synthesised in aqueous solution by a surface molecular imprinting in combination with a sol–gel process. This imprinted material was characterised by Fourier transform infrared, scanning electron microscopy, and static and kinetic adsorption experiments, and results showed that it had good recognition and selective ability, and fast adsorption‐desorption dynamics for olaquindox. Applying the prepared material as sorbent, a method of molecularly imprinted solid‐phase extraction (MISPE) for separation and analysis of olaquindox residues in feeds coupled with HPLC was presented. Under the selected MISPE condition, the detection limit (S/N = 3) for olaquindox was 68.0 ng L^?1, the RSD for five replicate extractions of 50 µg L^?1 olaquindox was 9.8%. The blank chick feed samples spiked with olaquindox at 0.0025 and 0.010 mg g^?1 levels were extracted and determined by the developed method, with recoveries ranging from 90% to 96%. CONCLUSION: This method was applied for enrichment and analysis of olaquindox in animal feed samples with good accuracy and repeatability. This study will provide a sensitive and fast method for the monitoring of olaquindox residues in foods. Copyright © 2011 Society of Chemical Industry     

Mass spectrometric analysis of muscle samples to detect potential antibiotic growth promoter misuse in broiler chickens

Mass spectrometric methods were developed and validated for the analysis in chicken muscle of a range of antibiotic growth promoters: spiramycin, tylosin, virginiamycin and bacitracin, and separately for two marker metabolites of carbadox (quinoxaline-2-carboxylic acid and 1,4-bisdesoxycarbadox), and a marker metabolite of olaquindox (3-methyl-quinoxaline-2-carboxylic acid). The use of these compounds as antibiotic growth promoters has been banned by the European Commission. This study aimed to develop methods to detect their residues in muscle samples as a means of checking for the use of these drugs during the rearing of broiler chickens. When fed growth-promoting doses for 6 days, spiramycin (31.4?µg?kg^?1), tylosin (1.0?µg?kg^?1), QCA (6.5?µg?kg^?1), DCBX (71.2?µg?kg^?1) and MQCA (0.2?µg?kg^?1) could be detected in the muscle 0 days after the withdrawal of fortified feed. Only spiramycin could consistently be detected beyond a withdrawal period of 1?day. All analytes showed stability to a commercial cooking process, therefore raw or cooked muscle could be used for monitoring purposes.     

Determination of olaquindox,carbadox and cyadox in animal feeds by ultra-performance liquid chromatography tandem mass spectrometry

Olaquindox, carbadox, and cyadox are chemically synthesised antibacterial and growth-promoting agents for animals. At high doses they may exert mutagenicity and hepatic and adrenal toxicities in animals. Regrettably, these substances are frequently abused or misused when added into animal feeds. Thus, developing a sensitive and reliable method for simultaneous determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds is crucially important for food safety monitoring. In this paper we optimised instrumental conditions, extraction solvents, solid phase extraction cartridges, and pH of the loading solvents on the Oasis HLB cartridge. Under the optimal conditions, mean recoveries ranged from 74.1 to 111%, and intra-day and inter-day variations were lower than 14.6% and 10.8%, respectively. The limits of quantification for olaquindox, carbadox, and cyadox were 0.05 mg kg^?1, 0.10 mg kg^?1, and 0.025 mg kg^?1, respectively. The proposed method uses ultra-performance liquid chromatography tandem mass spectrometry and is sensitive and reliable for the simultaneous determination of olaquindox, carbadox, and cyadox in three kinds of animal feeds (specifically, mixed feed, concentrated feed, and additive premixed feed). This method has good precision, high sensitivity, and good reproducibility, and thus it can be used for convenient and accurate determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds.     

In-house validation of an ELISA method for screening of semicarbazide in eggs

An enzyme-linked immunosorbent assay (ELISA) method is described for the semi-quantitative determination of semicarbazide (SEM), the marker residue for the banned nitrofuran drug, nitrofurazone, in chicken eggs. The sample homogenate is subjected to acid hydrolysis and derivatisation with o-nitrobenzaldehyde, followed by ethyl acetate/hexane extraction and detection by ELISA. The ELISA procedure has been validated using 0.3, 1.0 and 3 µg kg^?1 of SEM in fortified samples. Detection capability (CC_ß) was based on the acceptance of 5% false compliant results for a given concentration level according to Commission Decision 2002/657/EC and was determined to be 0.3 µg kg^?1 with a respective limit of detection of 0.13 µg kg^?1. A validated LC–MS/MS method was used for the analysis of incurred egg samples and the results compared with ELISA. A good correlation between the results obtained from ELISA and LC–MS/MS within the concentration range 0.12–20.3 µg kg^?1 was observed in samples collected from chickens fed with a medicated ration of nitrofurazone (r?=?0.992, n?=?14). Validated ELISA enabled reliable monitoring of SEM levels in eggs collected from incurred chickens over a 90-day period.     

Occurrence and intake of deoxynivalenol in cereal-based products marketed in Korea during 2007–2008

The occurrence of deoxynivalenol (DON) was investigated in 514 cereal-based products (corn-based, n = 125; barley-based, n = 96; wheat-based, n = 94; rice-based, n = 199) marketed in Korea during 2007?2008, and estimates of DON intake were determined. Samples were analysed by high-performance liquid chromatography (HPLC) with ultraviolet light (UV) detection after immunoaffinity clean-up. The limits of detection (LOD) and limits of quantification (LOQ) were 2.2 and 5.6 µg kg^–1, respectively. Recoveries and repeatability expressed as coefficients of variation (CV) were 82.3–100% and 2.4–15.3% in beer, bread and dried corn. The incidences and mean levels of DON were 56% and 68.9 µg kg^?1 for corn-based products, 49% and 24.1 µg kg^?1 for wheat-based products, 43% and 7.5 µg kg^?1 for barley-based products, and 16% and 3.4 µg kg^?1 for rice-based products, respectively. The estimated daily intake of DON from the consumption of rice-based, wheat-based, barley-based and corn-based products were 0.0038 µg kg^?1 bw day^?1, 0.0032 µg kg^?1 bw day^?1, 0.0015 µg kg^?1 bw day^?1 and 0.0002 µg kg^?1 bw day^?1, respectively. These values represent 0.38%, 0.32%, 0.25% and 0.01% of the provisional maximum tolerable daily intake (PMTDI) of 1 µg kg^?1 bw day^?1. These results indicate that rice-based products are major contributors to DON exposure in Korea, even though the current exposure level is unlikely to cause adverse health effects.     

Occurrence of ochratoxin A and citrinin in Czech cereals and comparison of two HPLC methods for ochratoxin A detection

The aims of the study were to obtain information about the occurrence of ochratoxin A (OTA) and citrinin (CIT) in cereals harvested in the Czech Republic and to compare two analytical procedures for detecting OTA. A total of 34 cereal samples, including two matrix reference materials (R-Biopharm, Germany), were analysed. The results were compared with the limit for raw cereal grains used as a foodstuff according to Commission Regulation No. 1881/2006, which allows a maximum OTA level of 5 µg kg^?1. Compared were two methods based on the high-performance liquid chromatography principle, one using the immunoaffinity columns OchraTest? (VICAM) and the second based on solvent partition (PART), both followed by fluorescence detection. The highest OTA contents were found in two barley samples. According to the method employed, the results for the first sample (malting barley) were VICAM = 31.43 µg kg^?1 and PART = 44.74 µg kg^?1. For the second sample (feeding barley) they were VICAM = 48.63 µg kg^?1 and PART = 34.40 µg kg^?1. Two samples of bread wheat had an OTA content approaching the legal limit (VICAM = 4.71 µg kg^?1 and PART = 6.03 µg kg^?1; VICAM = 4.12 µg kg^?1 and PART = 3.95 µg kg^?1). CIT was analysed using the PART method only, and its highest content (93.64 µg kg^?1) was found for the malting barley sample with high OTA content (44.74 µg kg^?1 as analysed using PART).     

Monoclonal-based enzyme-linked immunosorbent assay for the detection of zearalenone in cereals

A monoclonal antibody against zearalenone (ZEA) was produced and used successfully to develop a direct competitive enzyme-linked immunosorbent assay (DC-ELISA) for the analysis of ZEA in cereals. This DC-ELISA had a limit of detection of 0.15?±?0.02 µg l^?1 and an IC₅₀ value of 1.13?±?0.16 µg l^?1. Matrix interference was minimized by dilution of the sample extract before ELISA assays. Aqueous methanol (80%) gave good extraction efficiencies, and the recovery from spiked rice, barley, and corn samples averaged between 87 and 112%. Although ZEA was detected in seven (9%) of 80 rice samples and in eight (16%) of 50 barley samples, the concentration of ZEA in samples was around or below the limit of detection of DC-ELISA. Among 38 corn samples, ZEA was detected in nine (24%) samples in the range 41.0–909.8 µg kg^?1. Re-analysis of the ELISA-positive corn samples by high-performance liquid chromatography (HPLC) confirmed that seven (18%) corn samples were positive. The ZEA results for corn showed very good agreement between DC-ELISA and a commercial AgraQant® zearalenone kit (r ²?=?0.98). Thus, the monoclonal antibody-based DC-ELISA could be applied to the preliminary screening of ZEA contamination when analysis of a large sample number is needed.     

Aflatoxin M1 contamination in cow and buffalo milk samples from the North West Frontier Province (NWFP) and Punjab provinces of Pakistan

A total of 178 milk samples (94 of buffalo and 84 of cow) were randomly taken from Punjab and the North West Frontier Province (NWFP) of Pakistan (n?=?89 in each province) and analysed for the presence of aflatoxin M1 (AFM₁) by HPLC-FLD. From Punjab about 46% of buffalo's and 49% of cow's milks were contaminated with AFM₁ as compared with 52% and 51% for milk samples from NWFP, respectively. Overall, the mean AFM₁ concentration was 0.046?µg?kg^?1 with a maximum of 0.350?µg?kg^?1. All samples complied with the Codex Alimentarius limit of 0.50?µg?kg^?1 for AFM₁ in milk, but 16.3% of samples exceeded the European Union maximum level of 0.05?µg?kg^?1. Another set of 415 buffalo's and cow's milk samples (213 morning milks and 202 evening milks) were analysed. Statistical analysis revealed significant differences (p?<?0.05) between mean AFM₁ concentrations in milk during the morning (0.043?µg?kg^?1) and the evening (0.028?µg?kg^?1) lactation times.     

Occurrence of furan in commercial processed foods in Brazil

Selected commercial processed foods available in the Brazilian market (306 samples) were analysed for furan content using a validated gas chromatography-mass spectrometry method preceded by headspace solid phase micro-extraction (HS-SPME-GC/MS). Canned and jarred foods, including vegetable, meat, fruit and sweet products, showed levels up to 32.8?µg?kg^?1, with the highest concentrations observed in vegetables and meats. For coffee, furan content ranged from 253.0 to 5021.4?µg?kg^?1 in the roasted ground coffee and from not detected to 156.6?µg?kg^?1 in the beverage. For sauces, levels up to 138.1?µg?kg^?1 were found. In cereal-based products, the highest concentrations (up to 191.3?µg?kg^?1) were observed in breakfast cereal (corn flakes), cracker (cream crackers) and biscuit (wafer). In general, these results are comparable with those reported in other countries and will be useful for a preliminary estimate of the furan dietary intake in Brazil.     

Evaluation and validation of two microbiological tests for screening antibiotic residues in honey according to the European guideline for the validation of screening methods

Two microbiological kits based on Bacillus stearothermophilus (Eclipse 50® and Premi®Test) have been evaluated and validated according to the European guideline for the validation of screening methods (January 2010) and in relation to the concentrations recommended by the EU-RL in 2007. Both tests are robust, a fast method and easy to implement. Both tests are applicable to a very large variety of honeys from different floral and geographical origins (rosemary, lavender, scrub, heath, alder, forest, lemon, acacia, chestnut, raspberry, mountain and flowers) as well as honey of different colours (from blank honey to brown honey, including yellow and orange honey). A satisfactory false-positive rate of 5% was obtained for the Eclipse 50® test. The observed detection capabilities CCβ of the Eclipse 50® kit were: chlortetracycline (>75?µg?kg^?1), oxytetracycline (≤200?µg?kg^?1), tetracycline (>100?µg?kg^?1), cloxacillin (≤40?µg?kg^?1), tylosin (≤200?µg?kg^?1), desmycosin (>400?µg?kg^?1), sulfadiazine (≤300?µg?kg^?1), sulfadimethoxine (≤250?µg?kg^?1), sulfamerazine (>300?µg?kg^?1), sulfamethazine (>1000?µg?kg^?1), sulfamethizole (>75?µg?kg^?1), sulfamethoxazole (≤25?µg?kg^?1), sulfanilamide (?1000?µg?kg^?1), sulfaquinoxaline (>75?µg?kg^?1), sulfathiazole (≤250?µg?kg^?1) and lincomycin (>1500?µg?kg^?1). These levels were all higher than the recommended concentrations where they exist. Due to its lack of sensitivity, it cannot be recommended for reliable routine use. The observed CCβ of the Premi®Test kit were: chlortetracycline (10?µg?kg^?1), oxytetracycline (>10?µg?kg^?1), tetracycline (≤10?µg?kg^?1), cloxacillin (≤5?µg?kg^?1), tylosin (≤10?µg?kg^?1), desmycosin (≤15?µg?kg^?1), sulfadiazine (≤25?µg?kg^?1), sulfadimethoxine (≤25?µg?kg^?1), sulfamerazine (≤25?µg?kg^?1), sulfamethazine (≤25?µg?kg^?1), sulfamethizole (≤25?µg?kg^?1), sulfamethoxazole (≤10?µg?kg^?1), sulfanilamide (≤25?µg?kg^?1), sulfaquinoxaline (≤10?µg?kg^?1), sulfathiazole (25?µg?kg^?1) and lincomycin (≤25?µg?kg^?1). The Premi®Test kit could be recommended for reliable use in routine control due to its low detection capabilities (except for aminoglycosides), but the disadvantage is a high false-positive rate of 14%.     

Rapid screening method for quinolone residues in livestock and fishery products using immobilised metal chelate affinity chromatographic clean-up and liquid chromatography-fluorescence detection

An efficient LC method was developed for screening the presence of quinolones (QLs) – comprising fluoroquinolones (FQs) and acidic quinolones (AQs) – residues in various livestock and fishery products. Targeted analytes were for nine FQs of marbofloxacin (MAR), ofloxacin (OFL), norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), danofloxacin (DAN), orbifloxacin (ORB), difloxacin (DIF) and sarafloxacin (SAR), and three AQs of oxolinic acid (OXA), nalidixic acid (NAL) and flumequine (FMQ). Samples comprised ten different food products covering five matrices: muscle (cattle, swine and chicken), liver (chicken), raw fish (shrimp and salmon), egg (chicken), and processed food (ham, sausage and fish sausage). This method involved a simple extraction with (1:1) acetonitrile–methanol, a highly selective clean-up with an immobilised metal chelate affinity column charged with Fe³⁺, a fast isocratic LC analysis using a short column (20?mm?×?4.6?mm, 3?µm) with a mobile phase of (15:85:0.1) methanol/water/formic acid, and fluorescence detection (excitation/emission wavelengths of 295?nm/455?nm for FQs (495?nm for MAR), and 320?nm/365?nm for AQs). Among FQs, pairs of NOR/OFL, ORB/DIF and ENR/DAN were incompletely resolved. A confirmatory LC run with a Mg²⁺ containing methanolic mobile phase was also proposed for the samples suspected of being positive. The optimised method gave satisfactory recoveries of 88.5% (56.1–108.6%) and 78.7% (44.1–99.5%) for intra- and inter-day assays with relative standard deviations of 7.2% (0.7–18.4%) and 6.8% (1.4–16.6%), respectively. Limits of quantitation ranged from 0.8?µg?kg^?1 (DAN) to 6.5?µg?kg^?1 (SAR). This method was successfully employed to analyse 113 real samples and two positive samples were found: fish sausage (CIP 990?µg?kg^?1) and shrimp (ENR 20?µg?kg^?1).     

Rapid Screening of Quinoxaline Antimicrobial Growth Promoters and Their Metabolites in Swine Liver by Indirect Competitive Enzyme-Linked Immunosorbent Assay

Quinoxaline feed additives are antimicrobial growth promoters (AGPs); use three of them is permitted, and two of them are illegally used. It results in residue of quinoxaline AGPs and their metabolites in edible animal tissues, which are potentially harmful to human health. In order to effectively monitor the multiple residues of them in swine liver, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed based on polyclone antibody preparation. Protein conjugates were synthesized and immune to New Zealand white rabbit according to designed schemes. The effective antiserum with 50 % inhibiting concentration (IC₅₀) value of 1.34 μg?L^?1 was obtained. A new synthesized quinoxaline with similar chemical structure to olaquindox but longer spacer arm was used as coating antigen. Cross-reactivity of other four quinoxaline AGPs and their eight metabolites was tested; seven of them have cross-reactivity over 10 %, with IC₅₀ of 0.10–2.50 μg?L^?1. At the spike level of 1 to 100 μg?kg^?1 in swine liver, the recoveries of all compounds ranged from 80.14 % to 96.90 %, with the inter-day variation coefficient (CV) of 5.67–13.82 % and the intra-assay CV of 6.22–14.19 %. The limit of detection ranged from 0.03?±?0.002 to 0.79?±?0.05 μg?L^?1. Positive samples were determined by the ic-ELISA method and successfully confirmed by liquid chromatography-tandem mass spectrometry. The proposed ELISA is feasible for screening quinoxaline AGPs and their metabolites in swine liver.     

Assessment of dietary exposure to aflatoxin B1 from corn arepas in Colombia

ABSTRACT

The aim of this research was to evaluate dietary exposure to aflatoxin B1 (AFB₁) in corn arepas in Colombia. In addition, in this study an assessment considering compliance to the maximum level of AFB₁ (4 µg kg^?1) for this food was conducted. AFB₁ concentration data in corn arepas were obtained from 168 samples. The samples were collected from factories in 16 departments in Colombia. AFB₁ was quantified by High-Performance Liquid Chromatography with a fluorescence detector. Consumption data and body weight (b.w.) were measured from the 2005 Colombian National Survey of Nutritional Status. Probabilistic estimates were made by Monte Carlo simulation of dietary exposure and margin of exposure (MOE) segmented by age group. The results showed that 27% of corn arepa samples were contaminated with AFB₁, with an average concentration of 15.1 µg kg^?1 and a maximum value of 111.1 µg kg^?1. The stochastic dietary exposure assessment showed that the age group most exposed was children between 4 and 8 years old (10.014 ng (kg b.w. day)^?1). In addition, the MOE values for all age groups were lower than 10,000, indicating a potential risk for consumers. However, in the scenario where AFB₁ concentration level complies with the maximum limit of 4 µg kg^?1 AFB₁, the level of concern could be reduced for the adult population between 14 and 64 years old because the MOE value is above 10,000.     

Distribution of aflatoxins and fumonisins in dry-milled maize fractions

The aim was to evaluate the distribution of aflatoxins and fumonisins in fractions derived from the dry-milling of contaminated maize. Two maize lots with different contamination levels were processed and sampled: the first (maize 1) had aflatoxin B₁ (AFB₁) and fumonisin B₁ (FB₁) levels of 3.6 and 5379 µg kg^?1, respectively; the second (maize 2) had corresponding levels of 91.1 and 8841 µg kg^?1, respectively. The cleaning step reduced AFB₁ and FB₁ levels by 8 and 11% in maize 1 and by 57 and 34% in maize 2. The subsequent removal of bran and germ led to a further decrease in contamination levels in the products destined for human consumption. In the latter, AFB₁ was uniformly distributed, while FB₁ was concentrated in the finer size fractions. Contamination of raw maize 1 (3.6 µg kg^?1) was below the European Union AFB₁ limit of 5 µg kg^?1 for unprocessed maize, but among the final products only coarse flour (1.7 µg kg^?1) was within the European Union limit of 2 µg kg^?1, while grits and fine flour showed higher levels (2.7 and 2.5 µg kg^?1, respectively). As regards cleaned maize, a different distribution of the two toxins was observed in the kernels: AFB₁ contamination was more superficial and concentrated in germ, while FB₁ contamination affected the inner layers of the kernels.     

Aflatoxin M1 in raw milk from different regions of São Paulo state – Brazil

A total of 635 raw milk samples from 45 dairy farms, from three regions of São Paulo state – Brazil, were evaluated during 15 months for aflatoxin M₁ (AFM₁). AFM₁ was determined by high performance liquid chromatograph with fluorescence detection. AFM₁ was detected (>0.003 µg kg^?1) in 72.9%, 56.3% and 27.5% of the samples from Bauru, Araçatuba and Vale do Paraíba regions, respectively. The mean AFM₁ contamination considering all the samples was 0.021 µg kg^?1. Furthermore, the concentration of AFM₁ was quite different among Bauru (0.038 µg kg^?1), Araçatuba (0.017 µg kg^?1) and Vale do Paraíba (<0.01 µg kg^?1) regions. Only three samples (0.5%) had higher contamination than the tolerated limit in Brazil (0.50 µg kg^?1) and 64 samples (10.1%) had a higher contamination than the maximum limit as set by the European Union (0.050 µg kg^?1). The estimated AFM₁ daily intake was 0.358 and 0.120 ng kg^?1 body weight per day for children and adults, respectively.     

Aflatoxins and cyclopiazonic acid in feed and milk from dairy farms in São Paulo,Brazil

The occurrence of aflatoxins (AF) B₁, B₂, G₁, G₂ and cyclopiazonic acid (CPA) in feeds, and AFM₁ and CPA in milk was determined in dairy farms located in the northeastern region of São Paulo state, Brazil, between October 2005 and February 2006. AF and CPA determinations were performed by HPLC. AFB₁ was found in 42% of feed at levels of 1.0–26.4 µg kg^?1 (mean: 7.1 ± 7.2 µg kg^?1). The concentrations of AFM₁ in raw milk varied between 0.010 and 0.645 µg l^?1 (mean: 0.104 ± 0.138 µg l^?1). Only one sample was above the tolerance limit adopted in Brazil (0.50 µg l^?1) for AFM₁ in milk. Regarding CPA in feed, six (12%) samples showed concentrations of 12.5–153.3 µg kg^?1 (mean: 57.6 ± 48.7 µg kg^?1). CPA was detected in only three milk samples (6%) at levels of 6.4, 8.8 and 9.1 µg l^?1. Concentrations of aflatoxins and CPA in feed and milk were relatively low, although the high frequency of both mycotoxins indicates the necessity to continuously monitor dairy farms to prevent contamination of feed ingredients.