Determination of heavy metals in selected black sea fish species

Heavy metals can be accumulated by marine organisms thought a variety of pathways, including respiration, adsorption and ingestion. The levels of heavy metals are known to increase drastically in marine environment through mainly anthropogenic activities. Fish are good indicators for the long term monitoring of metal accumulation in the marine environment. The aim of this study was to determine the levels of Cd, As, Hg, Pb, Zn and Cu in edible part and gill of seven most consumed Bulgarian fish species collected from north-east coast of Black Sea. These fish species are sprat (Sprattus sprattus sulinus), Mediterranean horse mackerel (Trachurus mediterraneus ponticus), Black sea gobies (Neogobius melanostromus), shad (Alosa pontica), Atlantic bonito (Sarda sarda), bluefish (Pomatomus saltatrix) and grey mullet (Mugil cephalus). The fish samples were collected during 2010. The analytical determination of As, Cd, Pb, Zn and Cu were performed by using flame and graphite furnace atomic absorption spectrometry after microwave digestion procedure. The total mercury determination was determined using a direct mercury analyzer (DMA-80). The metal concentration of analyzed elements was highest in the gill for all fish species. The maximum metal concentration was measured for Cu (1.40 mg kg⁻¹ w.w), Zn (11 mg kg⁻¹ w.w) and Pb (0.08 mg kg⁻¹ w.w) in muscle tissues of shad and sprat. The edible part of horse mackerel has the maximum value for Hg (0.12 mg kg⁻¹ w.w) while Atlantic bonito predominantly accumulates As (1.10 mg kg⁻¹ w.w). The analytical results obtained from this study were compared within acceptable limits for human consumption set by various health institutions.     

Scope extension validation of a LC-MS method for the inspection of preservatives in butter

Butters are considered as “natural products” by many consumers, once they are obtained from milkfat without adding of any additive, except sodium chloride, starter cultures and natural dyes. The main goals of this study were to extend the scope of a previously developed method, including a new analyte (benzoic acid) and new matrices (butter and margarine), and thus evaluate the content of preservatives in national and imported butters traded in Brazil. Samples (n = 51) from inspected establishments in Argentina (n = 2), Brazil (n = 40), France (n = 7) and Uruguay (n = 2) were assessed by liquid chromatography-tandem mass spectrometry. Two screening inspection rounds were carried out between November, 2015 and January, 2016. Non-compliance rates were 36.4% in 2015 and 22.2% in 2016 for Brazilian butters. It was shown that preservatives are irregularly added to butters by many factories, contrary to regulation, and without proper declaration on labeling. The limits of quantitation (LOQ) were set to 25.00 mg kg⁻¹ (benzoic acid), 1.25 mg kg⁻¹ (natamycin), 3.13 mg kg⁻¹ (nisin) and 2.50 mg kg⁻¹ (sorbic acid). Except nisin, any of the researched preservatives was detected in a total of 12 samples, in concentrations that ranged from <LOQ–235.67 mg kg⁻¹ (benzoic acid), 8.26–35.60 mg kg⁻¹ (natamycin) and 4.52–1007.17 mg kg⁻¹ (sorbic acid). The method was also checked on margarine samples, revealing concentrations that ranged from 43.72 to 359.17 mg kg⁻¹ (benzoic acid) and from 509.00 to 1102.67 mg kg⁻¹ (sorbic acid), respectively. Our findings demonstrate that there is a need for stricter control in butter processing, with the aim to ensure food safety and to safeguard consumers.     

Saturated aqueous ozone degradation of deoxynivalenol and its application in contaminated grains

Deoxynivalenol (DON) is a secondary metabolite produced by Fusarium graminearum in grains, food and contaminated feed, which can lead to many adverse health effects to humans and livestock. The degradation of DON in different contaminated grains oxidated by saturated aqueous ozone (80 mg L⁻¹) was monitored by ultra-high-performance liquid chromatography, tandem-quadrupole-detection mass spectrometry (UPLC–TQD-MS). Results suggest that ozone has a significant effect on DON reduction in solution. When 80 mg L⁻¹ gaseous ozone was used to treat 10 mg L⁻¹ of DON solution, the degradation rate of DON reached 83% within 7 min, while the respective detoxification rates of contaminated wheat, corn and bran by saturated aqueous ozone (80 mg L⁻¹) were 74.86%, 70.65% and 76.21 in 10 min. Ozone at 80 mg L⁻¹ was applied on various DON solution concentrations at 1 mg L⁻¹, 10 mg L⁻¹ and 20 mg L⁻¹ in ultra-pure water. In this paper, the degradation procedure for DON is calculated and described by a first-order kinetic equation. At lower levels (20 mg L⁻¹) of aqueous ozone, intermediate degradation products were observed by ultra-ne quickly and effectively degrades DON and toxicity in various contaminated grains in a matter of minutes. Therefore, ozonation is projected to be an effective, fast, and safe method for DON degradation.     

Method development for the simultaneous determination of methylmercury and inorganic mercury in seafood

This paper reports the method development for the simultaneous determination of methylmercury (MeHg⁺) and inorganic mercury (iHg) species in seafood samples. The study focused on the extraction and quantification of MeHg⁺ (the most toxic species) by liquid chromatography coupled to on-line UV irradiation and cold vapour atomic fluorescence spectroscopy (LC-UV-CV-AFS), using HCl 4 mol L⁻¹ as the extractant agent. Accuracy of the method has been verified by analysing three certified reference materials and different spiked samples. The values found for total Hg and MeHg⁺ for the CRMs did not differ significantly from certified values at a 95% confidence level, and recoveries between 85% and 97% for MeHg⁺, based on spikes, were achieved. The detection limits (LODs) obtained were 0.001 mg Hg kg⁻¹ for total mercury, 0.0003 mg Hg kg⁻¹ for MeHg⁺ and 0.0004 mg Hg kg⁻¹ for iHg. The quantification limits (LOQs) established were 0.003 mg Hg kg⁻¹ for total mercury, 0.0010 mg Hg kg⁻¹ for MeHg⁺ and 0.0012 mg Hg kg⁻¹ for iHg. Precision for each mercury species was established, being ≤ 12% in terms of RSD in all cases.Finally, the developed method was applied to 24 seafood samples from different origins and total mercury contents. The concentrations for Total Hg, MeHg⁺ and iHg ranged from 0.07 to 2.33, 0.003–2.23 and 0.006–0.085 mg Hg kg⁻¹, respectively. The established analytical method allows to obtain results for mercury speciation in less than 1 one hour including both, sample pretreatment and measuring step.     

A fast and simple LC-ESI-MS/MS method for detecting pyrrolizidine alkaloids in honey with full validation and measurement uncertainty

A fast and simple method was developed to determine pyrrolizidine alkaloids (PAs) in honey using liquid chromatography tandem mass spectrometry (LC- MS/MS) with electrospray ionization (ESI). An efficient extraction procedure was carried out by simply diluting with water, without the need of any additional clean-up steps. A full validation of the method was performed according to Commission Decision 2002/657/EC. The method was linear in the 050 μg kg⁻¹ range and presented satisfactory intra-day and inter-day precision with relative standard deviations of 1.45–10.2% and 1.60–1–0.2%, respectively. The measurement uncertainty, limit of detection (LOD) (0.1–1.0 μg kg⁻¹) and limit of quantification (LOQ) (0.2–1.5 μg kg⁻¹) were also calculated. The proposed method was applied to analyse eight PAs, namely, senecionine, senecionine-N-oxide, echimidine, intermedine, lycopsamine, retrorsine, monocrotaline and retrorsine-N-oxide, in 92 commercial honey samples from Brazil. At least three PAs were detected in 99.1% of the samples. PAs were not detectable (<LOD) in only one sample. Because PAs are natural toxins biosynthesized by plants, the importance of monitoring their concentration in honey is evident. For this purpose, a simple, low-cost extraction procedure was performed, and a high-throughput method was developed.     

A multicommuted flow system for fast screening/sequential spectrophotometric determination of dichromate,salicylic acid,hydrogen peroxide and starch in milk samples

In this work a multicommuted flow system for the sequential screening/determination of dichromate, salicylic acid, hydrogen peroxide and starch in milk samples was developed. The concept of multicommutation in flow injection analysis was chosen, resulting in an environmentally friendly system with minimal consumption of reagents and waste generation. The proposed approach is based on a simple binary DETECT or NO-DETECT response, thereby making it possible to determine analytes quickly, with high performance and easy operation. For dichromate determination, the proposed method was based on the reaction between Cr(VI) and 1,5-diphenylcarbazide, enabling a linear working range response, between 1.0 and 10.4 mg L⁻¹, (R = 0.999). In order to determine salicylic acid, the proposed method was based on a complexation reaction of Fe(III) and salicylic acid, with the linear working range response from 103.6 to 414.3 mg L⁻¹ (7.5 × 10⁻⁴–3.0 × 10⁻³ mol L⁻¹) (R = 0.999). The hydrogen peroxide determination was based on the oxidation reaction of hydrogen peroxide with vanadium oxide (V) in an acid environment, with a linear working range of 10.0–200.0 mg L⁻¹ (R = 0.996). Starch determination was based on the complex reaction of starch and triiodide, with a linear working range of 12.5–150.0 mg L⁻¹ (R = 0.999). The mean sampling rate for the four species was 83 determinations per hour. Performance curves were used to verify the quantity of false positives and false negatives. Addition and recovery tests were used for validation of the proposed procedures, resulting in variation between 90.1 and 108.7% for three different samples.     

Development and validation of a new qualitative ELISA screening for multiresidue detection of sulfonamides in food and feed

An indirect competitive enzyme-linked immunosorbent assay (ELISA) to screen sulfonamide residues in food (muscle, eggs, milk and honey) and feed has been developed and validated according to Commission Decision 2002/657/EC. The immunoreagents were appropriately produced to detect a wide range of sulfonamide antibiotic congeners, obtaining half-maximum inhibition concentration (IC₅₀) values below 10 μg L⁻¹ for 11 sulfonamides widely used in veterinary practices. Taking into account the complexity of involved matrices, specific sample preparation protocols have been optimised combining high method throughput with low detectable concentrations. Accordingly, depending on the congener, the obtained detection capabilities (CCβs) were lower or equal to 20 μg kg⁻¹ (muscle, eggs and milk), 10 μg kg⁻¹ (honey) and 2 mg kg⁻¹ (feed). Finally the developed qualitative test was applied to real samples collected within the official monitoring programmes: results exceeding the established screening cut-off were re-analysed with a suitable confirmatory method. The presence of one or more sulfonamides was found in all the suspect screening samples thus demonstrating that the proposed ELISA can be successfully applied in class-specific detection of sulfonamides in food and feed.     

Chlorpyrifos residue levels on field crops (rice,maize and soybean) in China and their dietary risks to consumers

In this study, chlorpyrifos residue levels in field crops of rice, maize and soybean were investigated according to the “Guideline on Pesticide Residue Trials” of China. On the basis of the residual results, human dietary risks were further evaluated. Chlorpyrifos residues of harvest grains were firstly prepared by QuEChERS method and analyzed using Gas Chromatography Tandem Mass Spectrometry (GC–MS/MS). Dietary risks were assessed by a deterministic approach. The median residues in field trials of rice, maize and soybean were 0.617, 0.0227 and 0.0136 mg kg⁻¹, respectively. The highest residues in field trials of rice, maize and soybean were 3.23, 0.114 and 0.102 mg kg⁻¹, respectively. Chronic intake assessment indicated that only 39.0% of acceptable daily intake (ADI, 0–0.01 mg kg bw⁻¹ day⁻¹) was consumed through rice, maize and soybean. The acute hazard indexes (aHI) of adults was 26.1% of acute reference dose (ARfD, 0–0.1 mg kg bw⁻¹) and aHI of children was 63.5% of ARfD in dietary exposure assessment through rice, maize and soybean consumption. Single pathway risk assessment indicated that chlorpyrifos application on field crops in manner of the good agricultural practices didn't pose public health risks.     

High performance liquid chromatography method for the determination of patulin and 5-hydroxymethylfurfural in fruit juices marketed in Malaysia

A rapid, simple, improved method for the simultaneous determination of patulin (PAT) and 5-hydroxymethylfurfural (5-HMF) in fruit juices is described. The target compounds were extracted with ethyl acetate using vortex followed by high performance liquid chromatographic separation. PAT and 5-HMF were separated within 4 min using Poroshell C18 column with acetonitrile:water (1:9, v/v) as the mobile phase. Under the optimized conditions, the detection limits of PAT and 5-HMF were 0.25 and 0.46 ng mL⁻¹, respectively while the quantification limits were 0.76 and 1.40 ng mL⁻¹, respectively. The recoveries of PAT and 5-HMF at 50, 750 and 5000 ng g⁻¹ ranged from 92.8 to 108%. The proposed method was applied to fivety-six fruit juices (apple, mango, pineapple, guava, lychee, tamarind, soursop and mixed fruit) and PAT was found in three samples ranging from 13.1–33.7 ug L⁻¹. 5-HMF was found in all the samples ranging from 0.08 to 91.5 mg L⁻¹. Liquid chromatography-tandem mass spectrometry with triple quadrupole analyzer was used to confirm the presence of 5-HMF and PAT in some of the contaminated samples.     

Contamination levels for lead,cadmium and mercury in marine gastropods,echinoderms and tunicates

As part of a specific monitoring programme, total lead (Pb), cadmium (Cd) and mercury (Hg) concentrations in marine gastropods (common winkle, common whelk, abalone and murex), echinoderms (purple sea urchin and black sea cucumber) and tunicates (an ascidian species) were investigated by the French National Reference Laboratory (NRL) for trace elements in foodstuffs of animal origin. These elements were analysed by atomic absorption spectrometry in order to evaluate the safety of these species for human consumption. The highest levels of Hg and Cd were found in murexes, 0.185 mg kg^?1 and 0.853 mg kg^?1, respectively; whereas the highest level of Pb was detected in ascidians (0.505 mg kg^?1). Hg and Pb concentrations were always below the maximum levels set by the European legislation (0.5 mg Hg kg^?1 and 1.5 mg Pb kg^?1 wet mass) and for Cd, only 2 samples of murex (2.09 ± 0.42 mg kg^?1 and 2.33 ± 0.46 mg kg^?1) exceeded the maximum level set by French legislation of 2.0 mg kg^?1 wet mass.     

Should chlorate residues be of concern in fresh-cut salads?

Chlorine remains the most popular method used by the fresh produce industry for decontamination. However, the occurrence of disinfection by-products (DBP) derived from chlorine-based disinfectants has been highlighted as a problem. After recent reports, chlorate residues in fresh produce are of concern in Europe. This study evaluated the chlorate accumulation in process wash water and the residues in fresh-cut lettuce when sodium hypochlorite was used as a wash aid. At a commercial processing facility, total chlorine was continually added to achieve a free chlorine level of 1–80 mg L⁻¹ for water disinfection as the organic load measured as chemical oxygen demand (COD) increased over time (1000–1500 mg O₂ L⁻¹). This resulted in chlorate accumulation (19–45 mg L⁻¹) in the process water. When fresh-cut lettuce was washed in that water, chlorate residues were detected in the lettuce and the concentrations increased linearly with the repeated use of the same process water, reaching concentrations of 4.5–5.0 mg kg⁻¹. To understand the chlorate accumulation in the process wash water, several experiments were performed at a pilot plant scale with different levels of COD and free chlorine. There was a significant (p < 0.001) correlation (R = 0.91) between the total added chlorine and the chlorate accumulation in the process water. We demonstrated that the added chlorine needed to maintain a free chlorine level in the process water was the contributing factor to chlorate accumulation. Chlorate residues in the washed fresh-cut lettuce after rinsing for 1 min in tap water and in commercial bags were below the limit of quantification. This study contributes to the knowledge of chlorate accumulation in the process water when sodium hypochlorite was used as a sanitizer.     

Detection of selected corticosteroids and anabolic steroids in calf milk replacers by liquid chromatography–electrospray ionisation – Tandem mass spectrometry

The use of corticosteroids and anabolic steroids in food producing animals is regulated or banned in the European Union (EU). However, their use as growth promoters cannot be excluded. Milk replacers, considered by EU legislation as feeds, may be a good way of administration of these compounds. In order to improve the control of growth promoter utilization in animal husbandry and preventing possible consequences to animal welfare, we developed a method for multiresidue analysis of prednisolone, prednisone, dexamethasone, cortisone, cortisol, 17α- and 17β-boldenone and their precursor androstadienedione (ADD), testosterone, epitestosterone, 17α- and 17β-nandrolone, and trenbolone in powdered milk for calves. All analytes were extracted, after a common deproteinization and defatting sample pre-treatment, by a unique immunoaffinity column and analysed by liquid chromatography tandem mass spectrometry (LC–MS/MS) in both positive and negative electrospray ionization (ESI) modes. The method was validated according to the criteria of the Commission Decision 2002/657/CE. The analytical limits were from 0.39 to 0.73 ng mL⁻¹ for the decision limit (CCα) and 0.46–0.99 ng mL⁻¹ for detection capability (CCβ). The analysis of 50 samples of milk replacers for calves, always revealed the presence of cortisol and cortisone (average concentrations 2.56 and 1.06 ng mL⁻¹, respectively), frequently testosterone and epitestosterone (1.24 and 0.63 ng mL⁻¹, respectively), occasionally β-nandrolone (0.82 ng mL⁻¹) and prednisolone (0.41 ng mL⁻¹). The other anabolic steroids were never found.     

Application of solid phase extraction and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry for fast analysis of polycyclic aromatic hydrocarbons in vegetable oils

A fast and simple solid-phase extraction (SPE) method followed by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC–TOFMS) has been developed for analysis of 15 + 1 carcinogenic polycyclic aromatic hydrocarbons (PAHs) in vegetable oils. Of three critically assessed sample preparation approaches – (i) gel permeation chromatography (GPC), (ii) GPC followed by silica based SPE, and (iii) SPE employing PAHs-dedicated molecularly imprinted polymers (MIPs), the latter one was selected as the best option. Recoveries of the overall analytical procedure ranged from 70 to 99%, with repeatabilities in the range of 2–11%. Limits of quantitation (LOQs) ranging for individual PAHs from 0.1 to 0.3 μg kg⁻¹, were fairly below the maximum level 2 μg kg⁻¹ established for the PAHs representative, benzo[a]pyrene (BaP), by EU Legislation for this commodity. Within the mini-survey in which the new method was employed for examination of 35 samples of various kinds of vegetable oils collected at the Czech market, the highest PAH4 levels, i.e. the sum of BaP, benz[a]anthracene (BaA), benzo[b]fluoranthene (BbFA) and chrysene (CHR) were found in sea buckthorn (708 μg kg⁻¹) followed by rapeseed oil (99.8 μg kg⁻¹). Altogether 8 samples from 35 examined vegetable oils exceeded the maximum limit 2 μg kg⁻¹ for BaP and 10 samples exceeded 10 μg kg⁻¹ set for PAH4 which is fixed by Commission Regulation (EU) no 835/2011 for oils.     

Analysis of tetracyclines in chicken tissues and dung using LC–MS coupled with ultrasound-assisted enzymatic hydrolysis

The accurate measurement of tetracycline antibiotics (TCs) in complex matrices related to chicken raising is important for food control. It was experimentally demonstrated that conventional acid deproteination methods led to high losses of TCs because TCs were strongly bounded to protein aggregates. To eliminate this effect, an ultrasound-assisted enzymatic hydrolysis method was developed to break the three-dimensional structures of proteins and release the bound TCs. This not only significantly improved the recovery of TCs but also shortened the pretreatment time from 960 to 6 min. By combining this new deproteination method and a solid phase extraction clean-up, a suitable sample preparation was achieved for the analysis of TCs with LC–MS/MS. The established LC–MS/MS analysis of TCs provided good linear ranges in the order of 20–1000 μg L⁻¹ with the limits of detection ranging from 1.05 to 3.50 μg L⁻¹ for the tested TCs. The new method yielded recoveries of TCs in spiked chicken-related samples as high as 89.1%–102.4%, being much higher than those (23.5%–36.2%) obtained using the acid deproteination process. When this method was used to analyze five practical samples of manures, it gave residual concentrations of 0.9–4.2 and 1.3–4.0 mg kg⁻¹ for oxytetracycline and chlortetracycline, respectively.     

Determination of chloramphenicol,thiamphenicol, and florfenicol in fish muscle by matrix solid-phase dispersion extraction (MSPD) and ultra-high pressure liquid chromatography tandem mass spectrometry

An UPLC–MS/MS method based on matrix solid-phase dispersion (MSPD) was developed for the determination of chloramphenicol (CAP), thiamphenicol (TAP) and florfenicol (FF) in fish muscle. Muscle tissue was blended with octadecylsilyl-derivatized silica (C₁₈). A column made from the C₁₈/muscle tissue matrix was washed with n-hexane, after which CAP was eluted with acetonitrile/water (50:50, v/v) and partitioned into ethyl acetate. The final extract was evaporated, and reconstituted into methanol/water (10:90, v/v) for the analysis of UPLC–MS/MS. The correlation coefficient (r²) with each matrix-matched calibration curve is higher than 0.999. CCα and CCβ of the fenicols upon the method were ranged from 0.02 to 0.06 μg kg⁻¹ and 0.11–0.16 μg kg⁻¹ respectively. At the fortified levels, mean recoveries of the three compounds were ranged from 84.2% to 99.8%, and the RSDs were lower than 12%. The method was accurate and reproducible, being successfully applied to the monitoring of CAP, TAP and FF in fish samples obtained from the Chinese market.     

Molecularly imprinted polymer for extraction of patulin in apple juice samples

A new molecularly imprinted polymer (MIP) was prepared in a two-step process. First, SiO₂-γ-MPTS was obtained by mixing γ-methacryloxypropyltrimethoxysilane (γ-MPTS) and tetraethoxysilane (TEOS). Second, SiO₂-γ-MPTS was polymerized in the presence of patulin (PAT) as a template, maleic acid (MA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross linker, 2,2-azobis- (2- methylpropionitrile) (AIBN) as a precursor and acetonitrile as a porogen solvent. The prepared sorbent was successfully applied to selective solid phase extraction (SPE) of PAT in containing apple juices and the MIP@SPE method was validated. The optimum conditions for PAT extraction using the novel MIP@SPE were: 50 mg mass of adsorbent, sodium bicarbonate with (1%) acetic acid as washing solvent and 5 mL acetonitrile as eluting solvent. The developed MIP@SPE method had high selectivity and good affinity toward PAT and the recoveries of the target analyte were in the range of 82–98% with a precision of 3.03%–3.83% (RSD). In addition, a good linearity (r² > 0.99) within the range 0.1–10 mg L⁻¹ and a low LOD (8.6 μg L⁻¹) and LOQ (28.6 μg L⁻¹) were obtained. The test of reusability showed good results for at least 6 cycles.     

Occurrence of four mycotoxins in cereal and oil products in Yangtze Delta region of China and their food safety risks

A total of 76 cereal and oil products collected from Yangtze Delta region of China were analyzed for occurrences of aflatoxins (AFs), aflatoxin B₁ (AFB₁), ochratoxin A (OTA), deoxynivalenol (DON) and zearalenone (ZEN). The mycotoxins were determined by the standard detection procedures using immunoaffinity column clean-up coupled with fluorometer (or HPLC-UV). ZEN was the most prevalent toxin, with the incidence of 27.6% (range = 10.0–440.0 μg kg⁻¹), and 9.2% of the evaluated samples were contaminated with a concentration higher than that of the legislation limit of China (60 μg kg⁻¹). AFs and AFB₁ were detected in 14.5% of the samples analyzed, the concentrations ranging 1.1–35.0 μg kg⁻¹ for AFs, and 1.0–32.2 μg kg⁻¹ for AFB₁; 4.0% of the samples had the concentrations of AFs and AFB₁ higher than that of the corresponding legislation limits of China (5.0, 10.0 and 20.0 μg kg⁻¹ for different products). OTA was detected in 14.5% of the cereal and oil products collected; the concentrations ranged 0.51–16.2 μg kg⁻¹. Only 2 samples showed OTA levels higher than that of the legislation limit of China (5.0 μg kg⁻¹). DON was detected in 7.9% of the samples; the concentrations ranged 100–700 μg kg⁻¹, and none of the samples showed DON concentration higher than that of the legislation limit of China (1.0 mg kg⁻¹). A total of 15.8% cereal and oil products were contaminated with at least two mycotoxins (multiple contaminations with different combinations including AFs-ZEN, AFs-OTA-ZEN, OTA-ZEN, ZEN-DON, OTA-ZEN-DON). The dietary exposure assessment results indicated that AFs (AFB₁), OTA, DON and ZEN from cereal-based products represented a series health risk to both adults and children in Yangtze Delta region of China. This is the first report of safety evaluation associated with major mycotoxins for the area.     

Multi-mycotoxins analysis in ginger and related products by UHPLC-FLR detection and LC-MS/MS confirmation

The aim of this study was to optimize and validate a powerful method for the simultaneous analysis of aflatoxins B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁), G₂ (AFG₂) and ochratoxin A (OTA) in ginger and related products collected from local markets in Beijing, China. The optimized analytical procedure was based on immunoaffinity column (IAC) clean-up, followed by ultra-high performance liquid chromatography with fluorescence (UHPLC-FLR) detection. Limits of detection (LOD) and quantification (LOQ) for the five mycotoxins were 0.005–0.2 and 0.0125–0.5 μg kg⁻¹, respectively. The average recoveries ranged from 84.2 to 97.3% with relative standard deviations (RSDs) from 0.63 to 7.86% at three spiking levels. Good linearity was observed for the analytes with correlation coefficients all higher than 0.9995. The established method was applied to 30 samples of 10 different species of ginger and related products, and all positive samples were confirmed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The results showed that 5 samples of ginger products were contaminated with AFB₁ at 0.13–1.38 μg kg⁻¹, while 3 samples of ginger and 2 samples of ginger products were contaminated with OTA at 0.31–5.17 μg kg⁻¹. All the contamination levels were below the legally allowable limits.     

Simultaneous determination of ethyl carbamate,chloropropanols and acrylamide in fermented products,flavoring and related foods by gas chromatography–triple quadrupole mass spectrometry

A simultaneous determination method was established by gas chromatography–triple quadrupole mass spectrometry (GC–MS/MS) for ethyl carbamate, acrylamide and chloropropanols (1,3-dichloropropane-2-ol (1,3-DCP), 2,3-dichloropropane-1-ol (2,3-DCP), 3-monochloropropane-1,2-diol (3-MCPD) and 2-monochloropropane-1,3-diol (2-MCPD)) in fermented products, flavoring and related foods. Ethyl carbamate-d₅, 1,3-DCP-d₅, 3-MCPD-d₅ and acrylamide-d₃ were used as isotope internal standards for ethyl carbamate, DCPs, MCPDs and acrylamide, respectively. The sample was extracted and cleaned in one single step by a combined clean-up column packed with Extrelut™ NT and primary secondary amine (PSA). The concentrated extract was directly injected without derivatization, separated by an Innowax (cross-bonded polyethylene glycol) capillary column and measured by GC–MS/MS. The calculated limits of detection (LODs) in the sample matrix were 1.8, 1.0, 2.1, 5.3, 5.1 and 5.0 μg kg⁻¹ for ethyl carbamate, 1,3-DCP, 2,3-DCP, acrylamide, 3-MCPD and 2-MCPD, respectively. The average recoveries in different matrices at three spiked concentration levels (20, 100 and 400 μg kg⁻¹) were 88.6–112, 92.6–103, 92.1–106, 86.2–107, 90.4–109 and 91.0–105% with relative standard deviations (RSDs) (Average RSDs in bracket) of 4.4–10.2 (6.4%), 3.7–7.3 (5.4%), 3.9–7.7 (5.2%), 4.4–9.3 (6.4%), 4.1–10.7 (6.3%) and 3.7–7.9% (5.6%), respectively. Two to six contaminants were simultaneously found in some of the soy sauce samples. Ethyl carbamate, acrylamide, 3-MCPD and 2-MCPD were found in the instant noodle flavoring. Trace levels (<12 μg kg⁻¹) of ethyl carbamate, acrylamide or 3-MCPD were detected in tomato sauce and salad dressing. Both ethyl carbamate and acrylamide were found in some of the curry products and Chinese yellow rice wine. Only ethyl carbamate was found in beer and grape wine.     

Free and hidden fumonisins in Brazilian raw maize samples

Fumonisins are secondary metabolites produced primarily by fungi strains that belong to the genera Fusarium and Alternaria, which have been shown to be highly prevalent in maize crops. Some authors have documented the presence of hidden forms of fumonisins occurring in raw maize. This purpose of this study was to determine the occurrence of free and hidden fumonisins in raw maize. The concentrations of fumonisins in 72 naturally contaminated maize samples were analyzed using liquid chromatography coupled to mass spectrometry. The performance parameters of the method to determine free fumonisins forms (FB₁ and FB₂) and hydrolyzed fumonisins forms (HFB₁ and HFB₂) were evaluated using the standards from the Commission of the European Communities (Commission, 2002). The analytical methods employed fell within the established guidelines. The amount of total fumonisins measured based on the hydrolyzed forms (HFB₁ + HFB₂) was 1.5–3.8 times greater than the amount of free fumonisins (FB₁ + FB₂). The concentration of hidden fumonisins was calculated by subtracting the levels of free fumonisins from the total fumonisin levels. The levels of hidden fumonisins were calculated to be 0.5–2.0 times greater than the level of free fumonisins. A strong positive correlation (R = 0.97) was observed between free fumonisins (FB₁ + FB₂) and. total fumonisins (HFB₁ + HFB₂). Based on this correlation, a predictive model was generated to estimate the total fumonisin level based on the measured/reported free fumonisin concentration. These results show that the risk of exposure to fumonisins is likely underestimated if only free fumonisins are considered. However, the predictive model could be a novel approach to estimating the total amount of fumonisins in maize samples without needing to perform expensive and time-consuming analytical methods.