Accurate glutamate monitoring in foodstuffs by a sensitive and interference-free glutamate oxidase based disposable amperometric biosensor

L-Glutamate (L-Glu) is a well-known flavour enhancer that is present in several foodstuffs. Although L-Glu is generally recognized as safe, the use in foodstuffs remains controversial and then its fast and accurate monitoring represents an important issue. In this work a sensitive and interference-free disposable amperometric biosensor for glutamate monitoring in foodstuffs was developed. The biosensor was prepared by immobilizing glutamate oxidase through co-crosslinking with bovine serum albumin and glutaraldehyde onto a screen printed disposable platinum electrode modified with a permselective overoxidized polypyrrole film. The enzyme immobilization was optimized by using different experimental procedures. The optimized glutamate biosensor was integrated in a flow injection system and characterized in terms of linearity (0.005-1.0 mM, r² = 0.992), limits of detection (1.8 μM) and quantitation (5.4 μM), repeatability (RSD < 3%) and stability of response under operational conditions (up to 50 h, over 400 analysis). The biosensor showed also excellent anti-interference characteristics towards the main electroactive interferents present in food matrices, and this allowed the application to the accurate monitoring of glutamate in different foodstuffs.

Rapid quantitative analysis of Hg2+ residue in dairy products using SERS coupled with ACO-BP-AdaBoost algorithm

In this study, surface-enhanced Raman spectroscopy (SERS) coupled with multivariate calibrations were employed to develop a rapid, simple and sensitive method for determination of mercury ions residues in dairy products. Initially, spherical Au@SiO₂ core shell nanoparticles with highly enhancement effect were synthesized to serve as the SERS substrate. Afterwards, an optical sensor system, namely micro-Raman spectroscopy system, was constructed for rapid acquisition of Au@SiO₂-mercury ions spectra. Then, ant colony optimization (ACO) and genetic algorithm (GA) were applied comparatively for selecting the characteristic variables from the Savitzky Golay-First derivative (SG-FD) processing data for subsequent quantitative analysis. Eventually, both linear (PLS and SW-MLR) and nonlinear (BPANN and BP-AdaBoost) methods were used for modeling. Experimental results showed that the variables selection methods significantly improved the model performance. Especially for the ACO algorithm, and the ACO-BP-AdaBoost model achieved the best results with the higher correlation coefficient of determination (R² = 0.997), and lower root-mean-square error of prediction (RMSEP = 0.092) than other quantification models. Paired sample t-test exhibited no statistically significant difference (sig > 0.05) between the reference concentrations determined by inductively coupled plasma mass spectrometry (ICP-MS) and the predicted concentrations by ACO-BP-AdaBoost model in adulterated foodstuffs.

Simultaneous determination of 20 disperse dyes in foodstuffs by ultra high performance liquid chromatography-tandem mass spectrometry

A reasonable, high sensitive and accurate analytical method for the determination of 20 allergenic disperse dyes in foodstuffs was developed and validated. The obtained results showed that an ultra high liquid performance chromatography system - equipped with tandem quadrupole mass spectrometry (UHPLC-MS/MS) proved to be ideal for the selected method enabling multidimensional processing of the samples. Under optimized conditions, validation results showed excellent linearity (5-1000 µg/L, r² ≥ 0.997), limits of detection (LODs, 1.1-10.8 μg/kg), recoveries (60.2-110.3%) and precision (RSDs ≤ 12.6%) for the twenty disperse dyes under investigation. The developed method was successfully applied to the analysis of 20 disperse dyes in real foodstuffs demonstrating the validity and applicability of the current method for continuing monitoring of the selected dyes. The proposed UHPLC-MS/MS is thus proved to be a convenient, effective, sensitive and timesaving method for the isolation and determination of allergenic disperse dyes in edible packaging and other foodstuffs.

Bioaccumulation of PCDD/Fs in foodstuffs near Bien Hoa and Da Nang airbases: assessment on sources and distribution

In this survey, food items were collected from vicinities of Bien Hoa and Da Nang airbase and determined for polychloro-dibenzo-dioxins and polychloro-dibenzo-furans (PCDD/Fs) to assess their accumulation, distribution in the local food items, and risk of PCDD/F exposure through consumption of the local foods. Dioxin compounds were determined using isotope dilution method which is slightly modified from US-EPA method 1613B. The dioxin concentration was the highest in fish followed by eggs, chicken, meat (pork and beef), and vegetables. Particularly, in Bien Hoa airbase, the mean concentrations of dioxin on TEQ and lipid basis (except for vegetables) were 26 pg/g for fish, 13 pg/g for eggs, 20 pg/g for chicken, 4.5 pg/g for meat, and 0.34 pg/g fresh wt for vegetables. In Da Nang airbase, the mean levels of dioxin on TEQ and lipid basis were slightly lower, 12.9 pg/g for fish, 8.7 pg/g for eggs, 5.9 pg/g for chicken, 6.7 pg/g for meat, and 0.17 pg/g for vegetables. It has been interesting to observe that free-range chicken expose to higher level of dioxin than caged chicken. In some free-range chicken, the portion of 2,3,7,8-TCDD was relatively high and implying recent exposure to dioxin.

Concentrations and Health Risk Assessment of Trace Elements in Cereals, Fruits, and Vegetables of Bangladesh

This study was conducted to determine concentrations of five toxic trace elements (Cr, Ni, As, Cd, and Pb) in cereals, fruits, and vegetables of Bangladesh. The range of mass fractions (mg/kg) of Cr, Ni, As, Cd, and Pb in the foodstuffs was 0.090-2.5, 0.03-2.6, 0.13-1.7, 0.010-0.74, and 0.37-2.2, respectively. This study indicates that concentration of Cr, and Pb in fruits; As, Cd, and Pb in vegetables were higher than WHO/FAO maximum allowable concentration levels. The hazard index (HI) values for adults and children of the toxic elements in studied cereals, fruits and vegetables were higher than 1.0, suggesting non-carcinogenic adverse health hazard to the consumers. The estimated target carcinogenic risk (TCR) values were greater than the threshold level of 1.0 × 10^-4 for Cr and Cd in cereals and vegetables indicate potential cancer risk to both adults and children for consumption of the foodstuffs. The present study reveals that trace elements contamination in foodstuffs is a serious issue of concern in Bangladesh.

Toxigenic potential and antimicrobial susceptibility of Bacillus cereus group bacteria isolated from Tunisian foodstuffs

BACKGROUND

Despite the importance of the B. cereus group as major foodborne pathogens that may cause diarrheal and/or emetic syndrome(s), no study in Tunisia has been conducted in order to characterize the pathogenic potential of the B. cereus group. The aim of this study was to assess the sanitary potential risks of 174 B. cereus group strains isolated from different foodstuffs by detecting and profiling virulence genes (hblA, hblB, hblC, hblD, nheA, nheB, nheC, cytK, bceT and ces), testing the isolates cytotoxic activity on Caco-2 cells and antimicrobial susceptibility towards 11 antibiotics.

RESULTS

The entertoxin genes detected among B. cereus isolates were, in decreasing order, nheA (98.9%), nheC (97.7%) and nheB (86.8%) versus hblC (54.6%), hblD (54.6%), hblA (29.9%) and hblB (14.9%), respectively encoding for Non-hemolytic enterotoxin (NHE) and Hemolysin BL (HBL). The isolates are multi-toxigenic, harbouring at least one gene of each NHE and HBL complexes associated or not to bceT, cytK-2 and ces genes. Based on the incidence of virulence genes, the strains were separated into 12 toxigenic groups. Isolates positive for cytK (37,9%) harbored the cytK-2 variant. The detection rates of bceT and ces genes were 50.6 and 4%, respectively. When bacteria were incubated in BHI-YE at 30 °C for 18 h and for 5 d, 70.7 and 35% of the strains were shown to be cytotoxic to Caco-2 cells, respectively. The cytotoxicity of B. cereus strains depended on the food source of isolation. The presence of virulence factors is not always consistent with cytotoxicity. However, different combinations of enterotoxin genetic determinants are significantly associated to the cytotoxic potential of the bacteria. All strains were fully sensitive to rifampicin, chloramphenicol, ciprofloxacin, and gentamycin. The majority of the isolates were susceptible to streptomycin, kanamycin, erythromycin, vancomycin and tetracycline but showed resistance to ampicillin and novobiocin.

CONCLUSION

Our results contribute data that are primary to facilitate risk assessments in order to prevent food poisoning due to B. cereus group.

A review on organophosphate Ester (OPE) flame retardants and plasticizers in foodstuffs: Levels, distribution, human dietary exposure, and future directions

Given the ongoing studies on the adverse effects of organophosphate ester (OPE) flame retardants and plasticizers on human health, there is an increasing scientific interest in the risk of exposure to OPEs via dietary intake. Using peer-reviewed literature published up to 2018, this review surveyed and compiled the available and reported data on the concentrations and distributions of 30 OPEs based on their occurrence in various food samples from around the world. Regardless of sampling locations or food categories, 22 OPEs were detectable in at least one of analyzed sample, and there were clear variations in OPE levels among samples from different locations or food categories. For instance, cereals and fats/oils were the most contaminated by OPEs in China and Belgium, whereas fats/oils and desserts were the main polluted products in Sweden. In contrast, vegetables, fruits, fluid dairy products, and cereals were reported as the primary categories of food polluted by OPEs in Australia. Animal-based food categories such as eggs, fish and meat were the least contaminated, whereas the highest median OPE concentrations were found in meat and fish from the United State. The levels and distribution patterns of OPEs in foodstuffs demonstrated a tremendous difference even when collected from the same country and the same food item. Rice from China had the highest tris(2‑chloroethyl) phosphate (TCEP, mean: 29.8 ng/g dw) levels, whereas 2‑ethylhexyl‑diphenyl phosphate (EHDPP, mean: 4.17 ng/g ww), triphenyl phosphate (TPHP, mean: 26.14 ng/g ww), tris(2-chloroisopropyl) phosphate (TCIPP, mean: 0.87 ng/g ww) and tributyl phosphate (TNBP, median: 0.55 ng/g ww) concentrations were the highest in the same food category from Sweden, Belgium, Australia, and the United States, respectively. These discrepancies may be due to a variety of reasons such as differences in OPE physico-chemical properties, extent of usage, uptake, metabolic pathways, industrial food manufacturing processes, OPE level differences as a function of habitat, and accumulation and degradability of OPEs in different species. It is worth noting that, due to its worldwide usage in food packaging materials, EHDPP was more prominently found in processed food compared to non-processed food. Based on reported OPE levels in various foods, this review conducted a preliminary assessment of human exposure to OPEs through dietary intake, which suggested that the OPE estimated daily intake (EDI) for humans was around 880 ng/kg bw/day (95th percentile). This value was well below the corresponding OPE health reference dose given by the U.S. EPA (≥15,000 ng/kg bw/day). Even so, dietary exposure to OPEs via food intake may be not negligible based on some important factors such as dilution effects, cooking processes, and the contribution of as yet unknown means of OPE exposure. Overall, this review highlights several gaps in our understanding of OPEs in foodstuffs: 1) the investigation of contamination levels of OPEs in foodstuffs should be extended to other regions, especially North America and European countries, where OPEs are widely used and frequently detected in environmental samples, and 2) newly identified OPE derivatives/by-products, e.g., OP diesters and hydroxylated metabolites, which have been reported as end-products of OPE enzymatic metabolism or degradation through aqueous hydrolysis, and which may co-exist with parent OPEs, could also be screened with precursor OPEs in foodstuffs in future studies.

Tetrabromobisphenol A, hexabromocyclododecane isomers and polybrominated diphenyl ethers in foodstuffs from Beijing, China: Contamination levels, dietary exposure and risk assessment

Hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA) and polybrominated diphenyl ether (PBDEs) are three legacy brominated flame retardants (BFRs); however, they are still produced and used in China. In this study, these three BFRs were measured in commonly consumed animal-based and plant-based foodstuffs from Beijing, China, and the dietary intakes of these BFRs by adults in Beijing were estimated to assess the related health concerns. The median levels of TBBPA in animal-based foodstuffs ranged from <LOD to 8.03 ng/g lipid weight (lw), whereas those in all the plant-based food groups were lower than the LOD. The median levels of total HBCD in animal-based foodstuffs were from 1.14 to 5.65 ng/g lw, and α-HBCD was the predominant isomer. The median HBCD level in vegetables was 0.266 ng/g wet weight (ww), whereas γ-HBCD was the most abundant isomer. The median levels of total PBDEs in animal-based foodstuffs were from 3.22 to 13.7 ng/g lw, and BDE-209 was the most abundant congener, comprising a proportion of at least 85% of total PBDEs. The daily dietary intakes of TBBPA, HBCD and PBDEs for adults in Beijing were 2.52, 2.74 and 9.77 ng/kg body weight/day, respectively. Meat consumption was found to be the primary source of BFR dietary intake. A comparison between the calculated estimated daily intakes (EDIs) and the corresponding threshold reference values (TRVs) indicated that daily intake of BFRs via food consumption is unable to cause significant health risks. Likewise, the margin of exposures (MOEs) calculated following the European Food Safety Authority (EFSA) approach were far higher than the threshold, which also proved that the EDIs of BFRs are unlikely to raise significant health concerns.

Quantitative method for conjugated metabolites of bisphenol A and bisphenol S determination in food of animal origin by Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry

With the objectives of both generating bisphenols (BPs) conjugates occurrence data in food from animal origin but also investigating the origin of associated contamination, the present study deals with the development of an efficient analytical method aiming at monitoring both BPA and BPS conjugated metabolites in food from animal origin. The objective of such monitoring is to determine the origin of BPs contamination (FCM or animal contamination). The targeted compounds were BPA-monoglucuronide (BPA-1G), BPA-diglucuronide (BPA-2G), BPA-monosulfate (BPA-1S), BPA-disulfate (BPA-2S) and BPS-monoglucuronide (BPS-1G). The developed standard operating procedure includes a preliminary solid-liquid extraction step followed by two successive solid phase extraction (SPE) stages, using successively a non-polar phase and a strong cation exchange polymer. Quantification was achieved according to both the isotopic dilution and surrogated quantification methods, using ¹³C-BPA-1G and BPA-d₆-1S as internal standards. Linearity was validated (R² > 0.99) for each molecule within the concentration range [0-10] μg kg^-1. Detection limits ranged from 0.02 μg kg^-1 (BPA-1G in muscle, BPA-1S and BPA-2G in liver) to 0.50 μg kg^-1 (BPA-2S in muscle). The strategy was then proven on liver samples collected from pregnant ewes subcutaneously exposed to BPA during 105 days, at 50 μg kg^-1 per day. BPA-1G, BPA-2G and BPA-1S were detected and quantified at a concentration of 3.81 μg kg^-1, 0.80 μg kg^-1 and 0.09 μg kg^-1, respectively. The analytical method was finally implemented on fifty unpacked food samples from animal origin in which significant free BPA concentrations were previously measured. Since no metabolites of BPA could be measured (<LOD), it means that such free BPA present in the samples originates from direct contact of the food item with a material containing BPA.

Health risks to local residents from the exposure of heavy metals around the largest copper smelter in China

Non-ferrous smelting releases lots of heavy metals to the environment. Although numerous studies have focused on pollution in the environment, fewer have studied the adverse health effects. In the current study, samples of food, hair and urine were collected and analyzed for zinc (Zn), iron (Fe), chromium (Cr), nickel (Ni), lead (Pb) and copper (Cu) from residents of 3 villages near the largest copper smelter in China. The estimated daily intake (EDI), target hazard quotient (THQ), and Hazard Index (HI) were used to estimate and analyze the health risks to local residents (children, adults, and seniors). The Zn, Cr, Ni, Fe, Pb and Cu concentrations in food ranged from 16.02 to 61.48 mg kg^-1, 0.23-13.64 mg kg^-1, 0.10-5.90 mg kg^-1, 19.16-170.05 mg kg^-1, 0.15-3.62 mg kg^-1, and 0.53-2.74 mg kg^-1, respectively. Zn, Cr, Ni and Pb concentrations in all vegetables were above the national tolerance limits. Children had higher EDIs of heavy metals than that of adults and seniors. The THQ of single elements and the HI of combined elements indicated that the EDI of Pb and Cu showed the highest potential health risks, followed by the EDI of Zn and Fe, and Ni, Cr. High EDI of heavy metals resulted in much higher concentrations of heavy metals in hair and urine samples than those of normal Chinese residents, showing that residents around the smelter have potential health risks through daily food intake. The main sources of these heavy metals were from the consumption of rice and vegetables and it is imperative that measures should be taken to control this urgent problem.

Development and validation of a ready to use cryo-EROD assay for the standardized screening of dioxins and dioxin-like compounds in foodstuffs

Recent European regulations have indicated the need for new bioanalytical screening methods capable of monitoring dioxin and dioxin-like compounds in foodstuffs and environmental samples, cost-effectively and with a quicker turnaround. Cryo-cells of the hepatic H4IIE line preserved in 96-well plates were exposed to sample extracts prepared from various foodstuffs and analysed for their content of dioxins and dioxin-like compounds by means of the 7-Ethoxyresorufin-O-Deethylase (EROD)-assay in two laboratories. Assay data were compared between both laboratories and results from instrumental analysis used as a confirmatory method. Additionally, cut-off values for the different studied matrices were derived. The current European regulation regarding methods of analysis for the control of foodstuffs was applied with the aim of determining the feasibility of the cryo-methodology. Results obtained in both laboratories were in congruence with the required validation parameters of the Commission Regulation (EU) No 2017/644. Cut-off values should be established matrix-dependent to reduce the rate of false compliant results and to keep the rate of false non-compliant results under control. In summary, the ready-to-use cryo-assay method for the bioanalytical screening of foodstuffs in control laboratories without cell-culture facilities has successfully proven to be accurate, far quicker and more cost effective than current methods.

Concentrations and health risks of heavy metals in soils and crops around the Pingle manganese (Mn) mine area in Guangxi Province, China

Heavy metal concentrations in agricultural fields and their ecological risks are a source of extensive concern worldwide. A field survey was conducted to investigate the present situation and health risks of heavy metals (Mn, Pb, Zn, Cu, and Cd) and crops (corn, green soybean, sweet potato, persimmon, cassava, and Chinese chestnut) around the Pingle manganese (Mn) mine site in Guangxi Province, China, which was abandoned 20 years ago. The results showed that the ranges of Mn, Pb, Zn, Cu, and Cd were 2706.54-6760.16, 229.37-275.84, 160.39-215.48, 58.11-75.30, and 5.78-6.98 mg kg^-1, respectively, which were approximately 15.38-38.41, 11.76-14.15, 2.12-2.85, 2.09-2.71, and 21.64-28.75 times greater than their respective background values. Most of these concentrations exceeded the national standard for soil quality (grade 2) developed by the Ministry of Environmental Protection of China (1995). Contamination assessments based on the single contamination index (P_i), Nemerow multi-factor index (P_com), and potential ecological risk index (RI) showed that the sampled soils were severely polluted with these heavy metals, especially Pb and Cd. Similarly, the crops were enriched with Pb and Cd, with concentrations of 10.22-41.78 and 2.33-5.37 mg kg^-1, respectively, which were much higher than the threshold values of the national food standards. Contamination assessments with P_i and P_com also showed that the crops were severely polluted with Pb and Cd. The bioaccumulation factor values for Cd were highest among the heavy metals, with an average mean of 0.66 in these six crops, demonstrating that Cd readily accumulates in these crops. An assessment showed that the health risk for adults living in the mining-impacted areas was significant. Our study strongly recommends that heavy metal contamination in agricultural soils and crops grown around the Pingle Mn mining-affected areas should be treated to mitigate the health risks.

Levels of PCDD/Fs in foodstuffs in Tarragona County (Catalonia, Spain): Spectacular decrease in the dietary intake of PCDD/Fs in the last 20 years

In this study, we determined the levels polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in 45 "composite" samples of food items belonging to 12 food groups. Foodstuffs were purchased in various locations of Tarragona County, Catalonia, Spain. The daily dietary intake of PCDD/Fs was subsequently estimated for the population living in that County. The highest toxic equivalent (WHO-TEQ) value corresponded to fish (0.103 ng/kg ww), followed by seafood (0.071 ng/kg ww) and eggs (0.070 ng/kg ww). In contrast, the lowest PCDD/F concentrations corresponded to vegetables, tubers, pulses, and fruits (each, 0.003 ng/kg ww). The current dietary intake of PCDD/Fs by the adult population was estimated in 8.54 pg WHO-TEQ/day, being fish and seafood the food groups with the greatest contribution to the dietary exposure of PCDD/Fs, followed by eggs, as well as by meat, oils and fats. The current study shows a continued decrease in the exposure to PCDD/Fs by the general population of Tarragona County since the first survey in the area conducted in 1998. The reduction observed in the last 20 years (from 210 pg I-TEQ/day to 8.54 pg WHO-TEQ/day) is certainly spectacular. The current daily intake (0.122 pg WHO-TEQ/kg bw) is also lower than most intakes recently reported in a number of regions and countries.

Rapid and visual detection of aflatoxin B1 in foodstuffs using aptamer/G-quadruplex DNAzyme probe with low background noise

Contamination of foods by aflatoxin B1 (AFB1) is a common serious problem. To improve the efficiency of AFB1 detection, this study aims to develop a sensitive aptasensor for detection of AFB1 in food samples based on the catalytic effect of aptamer/G-quadruplex DNAzyme probe. The resulting reassembly of this probe in the presence of hemin and K⁺ catalyzes the generation of fluorescent 2,3-diaminophenazine (DAP) from o-phenylenediamine (OPD). Interestingly, we first found that the high background induced by the superfluous hemin can be effectively suppressed with the aid of sequential adsorption and magnetic separation by magnetic oxidized multiwall carbon nanotubes (Fe₃O₄@oMWCNTs). This aptasensor exhibits a high sensitivity toward AFB1 with a detection limit of 0.02 ng/mL. The assay also shows higher selectivity for AFB1 compared to other reported agents and can be employed to detect AFB1 in foodstuffs, which might find broad practical applications in other food contaminants determination.

Assessment of metal levels in foodstuffs from the Region of Valencia (Spain)

Concentrations of lead, mercury, cadmium, arsenic, tin, copper and chromium were measured in a study carried out in 2010-2011. A total of 8100 food samples were collected and composite samples for 12 food groups were analysed for metal concentration levels. Metal levels were, in general, below the maximum levels set by the current European legislation. The fish group presented the highest Cd, Hg and As levels, whereas sweeteners and condiments group was the most contaminated food group by Pb, Cr and Sn and the meat group had the highest concentrations of Cu. The results of this study are generally similar to or lower than those observed in other studies conducted in other countries, except in the case of Hg, for which high values were obtained, mainly in swordfish. In addition, this survey confirms a decreasing tendency when compared with other studies carried out in Spain.

Occurrence of polybrominated diphenylethers, hexabromocyclododecanes, bromophenols and tetrabromobisphenols A and S in Irish foods

The occurrence of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), tetrabromobisphenol A (TBBPA) and other phenolic brominated flame retardants (BFRs) in Irish foodstuffs has been assessed. A total of 53 food samples including eggs, milk, fish, fat and offal were tested. Eighty-one percent of the samples contained at least one measurable PBDE congener. The most abundant and frequently occurring congeners were BDE-47, BDE-49, BDE-99, BDE-100 and BDE-209 with the highest concentrations found in fish, fat and eggs. Summed concentrations for the measured PBDEs ranged from 0.02 μg/kg to 1.37 μg/kg whole weight. At least one HBCD stereoisomer was found in twenty-six percent of the samples with α-HBCD being the most frequently detected. The highest concentrations were found in fat and oily fish samples. TBBPA was only detected in one farmed salmon sample at 0.01 μg/kg. Bromophenol residues were found in fourteen out of the 53 samples, specifically in eggs and fish, with concentrations ranging from 0.28 to 0.98 μg/kg whole weight. These data contribute to the EU-wide EFSA risk assessment on these contaminants that is currently underway.

Dietary exposure to HCH and DDT congeners and their associated cancer risk based on Pakistani food consumption

Dietary exposure to organochlorine pesticides such as hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) congeners was assessed using diet study approach, and for this purpose, different food items were collected in August 2014. The levels of ∑(HCHs + DDTs) in different food groups were ranged from 2.57 to 206 ng g^-1, ww, with contamination order of fish > poultry > milk > vegetables > cereals > flour > fruits. In the present study, the ratios of β-HCH/∑HCH (0.19-0.40) were < 0.5, where the ratios of (DDE + DDD)/∑DDT (0.48-6.70 with mean value of 0.61) were > 0.5 demonstrated the recent and past inputs of HCH and DDT, respectively. The major contributing groups (6.3-70.3%) to total dietary intake of HCHs and DDTs were animal origin (fish, poultry, and milk), while the less contributing food groups (2-4.5%) were vegetarian origin (vegetables, cereals, flour, and fruits). Cancer risk was estimated for HCHs and DDTs ingested via local foodstuffs. On the basis of both average and high end (95th percentile) exposure levels, the HRs for HCHs and DDTs were found greater than one (safety limit), indicating a potential cancer risk for Pakistani people from life-time consumption of contaminated food items selected in this study. The congener-specific cancer risk was found in order of α-HCH > β-HCH > ∑DDT > γ-HCH > p,p'-DDE > p,p'-DDT. Graphical abstract ᅟ.

Development of an immunoaffinity column for the highly sensitive analysis of bisphenol A in 14 kinds of foodstuffs using ultra-high-performance liquid chromatography tandem mass spectrometry

An immunoaffinity clean-up material based on a monoclonal antibody (mAb) has been prepared for concentrating and purifying bisphenol A (BPA) in 14 kinds of foodstuffs at trace level. Haptens and immunogen of bisphenol A have been synthesized and comprehensively characterized. An mAb towards BPA was prepared and cross-reactivities with 14 BPA analogues were below 5%. The prepared antibody was coupled to N-hydroxysuccinimide-activated Sepharose 4B to manufacture an immunoaffinity column (IAC), which was applied to purify BPA in 14 kinds of foodstuffs. The analyte was then detected by means of ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Under the optimized conditions, compared with two traditional SPE clean-up methods, the IAC showed better selectivity (matrix effect <16.8%) and higher sensitivity. The limits of detection for BPA in 14 kinds of foodstuffs ranged from 0.001 μg L^-1 to 0.01 μg kg^-1, and the limits of quantification were in the range from 0.003 μg L^-1 to 0.04 μg kg^-1. The recoveries of BPA from spiked samples ranged from 82.0% to 104.9%, with RSDs below 13.8%. Besides, the IAC exhibited good reusability, with 40% column capacity remaining and no significant loss of recovery after 25 application cycles in real sample detection. These results demonstrated that the developed IAC-UPLC-MS/MS approach has wide applicability for purifying and detecting BPA in various foodstuffs.

Residuals of organophosphate esters in foodstuffs and implication for human exposure

Foodstuffs may be contaminated by organophosphate esters (OPEs) and become an important source of human exposure since OPEs are ubiquitous in the environment. In the present study, 10 OPEs were analyzed in various food matrices collected from a city in Eastern China including chicken, pork, fishes, vegetables, tofu, eggs, milk and cereals. The concentrations of Σ₁₀OPEs ranged from 1.1 to 9.6 ng g^-1 fresh weight (fw) in the foodstuffs. Cereals had the highest residual level of total OPEs with a mean value of 5.7 ng g^-1 fw. Tris(2-ethylhexyl) phosphate was detected in all foodstuff samples and showed the highest median residual concentration of 1.3 ng g^-1 fw among the OPE analogs. The daily dietary intake of OPEs was calculated as 3.6 and 2.4 μg d^-1 for adults and children. Cereals were identified as the major contributor to the total OPEs among different types of foodstuffs. Preliminary exposure assessment revealed that the current non-cancer health risks of OPEs via dietary intake were in the range of 10^-5-10^-3, indicating low risk levels. Moreover, the hazard index of OPEs indicated that the risk for children (3 × 10^-3) was higher than adults (2 × 10^-3).

Chromium speciation in foodstuffs: A review

Numerous critical reviews have evaluated exposure to toxic and carcinogenic hexavalent chromium (Cr(VI)) from a number of pathways; including workplace air, cement and packaging materials. The contribution of foodstuffs to dietary Cr(VI) has been increasingly under investigation, however no summary of this work has been carried out. The objective of this article is to review the last twenty years of chromium speciation research in foodstuffs. Alkaline extraction, used for chromium speciation in other solids, is the most widely-reported procedure. Previous measurement of Cr(VI) in foodstuffs is questionable due to the reducing power of organic matter and antioxidants, leading to the development of speciated isotope dilution mass spectrometry (SIDMS) techniques to monitor interconversions. Evaluation of the genotoxicity of trivalent chromium (Cr(III)), which acts through a different pathway to that of Cr(VI), requires reconsideration towards measurement of Cr(III), which is present at higher concentrations in foodstuffs following reduction of the more-bioavailable Cr(VI).

A rapid method for simultaneous quantification of 13 sugars and sugar alcohols in food products by UPLC-ELSD

A novel, rapid, simultaneous analysis method for five sugars (fructose, glucose, sucrose, maltose, and lactose) and eight sugar alcohols (erythritol, xylitol, sorbitol, mannitol, inositol, maltitol, lactitol, and isomalt) was developed using UPLC-ELSD, without derivatization. The analysis conditions, including the gradient conditions, modifier concentration and column length, were optimized. Thirteen sugars and sugar alcohols were separated well and the resolution of their peaks was above 1.0. Their optimum analysis condition can be analyzed within 15min. Standard curves for sugars and sugar alcohols with concentrations of 5.0-0.1% and 2.0-0.05% are presented herein, and their correlation coefficients are found to be above 0.999 and the limit of detection (LOD) was around 0.006-0.018%. This novel analysis system can be used for foodstuffs such as candy, chewing gum, jelly, chocolate, processed chocolate products, and snacks containing 0.21-46.41% of sugars and sugar alcohols.

Migration of aluminum from food contact materials to food-a health risk for consumers? Part III of III: migration of aluminum to food from camping dishes and utensils made of aluminum

BACKGROUND

When cooking on a barbecue grill, consumers often use aluminum grill pans. For one, the pan catches the fats and oils that would drip into the embers causing the formation of potentially noxious smoke, and the pan also protects the food from being burned by direct heat from the coals. In addition, new aluminum products for use in ovens and grills are becoming increasingly popular. Due to their light weight and excellent heat transfer camping, utensils made of aluminum are, for example, often used by fishermen and mountain climbers. Preparing food in aluminum utensils can, however, result in migration of the aluminum to the foodstuffs.

RESULTS/CONCLUSIONS

In this study presented here, it was found that the transfer limit of 5.00 mg/L for aluminum is not exceeded using simulants for oil or for tap water; however, with an aqueous solution of 0.5% citric acid, the limit is clearly exceeded at 638 mg/L. This means that the Tolerable Weekly Intake (TWI) is exceeded by 298% for a child weighing 15 kg and for an adult weighing 70 kg it is equivalent to 63.8% of the TWI, assuming a daily uptake of 10 mL marinade containing lemon juice over a period of 1 week. Preparation of a fish dish with a marinade containing lemon juice in camping dishes would result in the TWI being exceeded by 871% for a child weighing 15 kg and by 187% for an adult weighing 70 kg assuming a daily uptake of 250 g over a period of 1 week.

Reconstruction of radionuclide intakes for the residents of East Urals Radioactive Trace (1957-2011)

The East Urals Radioactive Trace (EURT) was formed after a chemical explosion in the radioactive waste-storage facility of the Mayak Production Association in 1957 (Southern Urals, Russia) and resulted in an activity dispersion of 7.4 × 10¹⁶ Bq into the atmosphere. Internal exposure due to ingestion of radionuclides with local foodstuffs was the main factor of public exposure at the EURT. The EURT cohort, combining residents of most contaminated settlements, was formed for epidemiological study at the Urals Research Center for Radiation Medicine, Russia (URCRM). For the purpose of improvement of radionuclide intake estimates for cohort members, the following data sets collected in URCRM were used: (1) Total β-activity and radiochemical measurements of ⁹⁰Sr in local foodstuffs over all of the period of interest (1958-2011; n = 2200), which were used for relative ⁹⁰Sr intake estimations. (2) ⁹⁰Sr measurements in human bones and whole body (n = 338); these data were used for average ⁹⁰Sr intake derivations using an age- and gender-dependent Sr-biokinetic model. Non-strontium radionuclide intakes were evaluated on the basis of ⁹⁰Sr intake data and the radionuclide composition of contaminated foodstuffs. Validation of radionuclide intakes during the first years after the accident was first carried out using measurements of the feces β-activity of EURT residents (n = 148). The comparison of experimental and reconstructed values of feces β-activity shows good agreement. ⁹⁰Sr intakes for residents of settlements evacuated 7-14 days after the accident were also obtained from ⁹⁰Sr measurements in human bone and whole body. The results of radionuclide intake reconstruction will be used to estimate the internal doses for the members of the EURT cohort.

Patterns and dietary intake of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in food products in China

The health risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like PCBs (dl-PCBs) to human being should be assessed regularly. To evaluate the contamination levels in various food products in the Chinese market and to assess the dietary exposure of the Chinese population, 11 varieties of food groups totaling 634 samples including beef and mutton, chicken and duck, pork, fish and seafood, milk and dairy products were evaluated. The average concentrations of PCDD/Fs in all groups ranged from 0.291 to 8.468pg/g whole weight (w.w.). The average toxic equivalency concentrations were from 0.012pg TEQ/g w.w. for cereal to 0.367pg TEQ/g fat for marine oil. OCDD and 2,3,7,8-TCDF were the dominant congeners in foodstuffs. The dietary estimated mean intake for the Chinese rural and urban populations were 0.656 and 0.514pg TEQ/kg body weight/day, respectively, however, the cereal group exposure were higher to the estimate daily intake and contributed 81% for rural and 48% for urban population, followed by fish and seafood which contributed 4% and 16% to the estimate daily intake. The estimated dietary intakes were compared with the toxicological reference values and showed that both rural and urban populations were well below those values.

Supercritical fluid chromatography for lipid analysis in foodstuffs

The task of lipid analysis has always challenged separation scientists, and new techniques in chromatography were often developed for the separation of lipids; however, no single technique or methodology is yet capable of affording a comprehensive screening of all lipid species and classes. This review acquaints the role of supercritical fluid chromatography within the field of lipid analysis, from the early developed capillary separations based on pure CO₂ , to the most recent techniques employing packed columns under subcritical conditions, including the niche multidimensional techniques using supercritical fluids in at least one of the separation dimensions. A short history of supercritical fluid chromatography will be introduced first, from its early popularity in the late 1980s, to the sudden fall and oblivion until the last decade, experiencing a regain of interest within the chromatographic community. Afterwards, the subject of lipid nomenclature and classification will be briefly dealt with, before discussing the main applications of supercritical fluid chromatography for food analysis, according to the specific class of lipids.