Quantification of aflatoxin B1 in vegetable oils using low temperature clean-up followed by immuno-magnetic solid phase extraction

Magnetic-gold nanoparticle-mediated paper-based biosensor for highly sensitive colorimetric detection of food adulteration

Food adulteration presents a significant challenge due to the evasion of legal oversight and the difficulty of identification. Addressing this issue, there is an urgent need for on-site, rapid, visually based small-scale equipment, along with large-scale screening technology, to enable prompt results without providing opportunities for dishonest traders to react. Colorimetric reactions offer advantages in terms of speed, visualization, and miniaturization. However, there is a scarcity of suitable colorimetric reactions for food adulteration detection, and interference from colored food impurities and easily comparable color results affects accuracy. To overcome limitations, this study introduces a novel approach utilizing polydopamine magnetic nanoparticles to enrich DNA in food samples, effectively eliminating interfering components. By employing gold nanoparticles to generate magnetic-gold nanoparticles, a single magnetic bead achieves simultaneous enrichment, impurity removal, and detection. The use of paper-based biosensors and visualization equipment allows for the visualization and digital analysis of results, achieving a low detection limit of 4.59 nmol mL-1. The method also exhibits high accuracy and repeatability, with a RSD ranging from 1.6 % to 4.0 %. This innovative colorimetric method addresses the need for rapid, miniaturized, and large-scale detection, thus providing a solution for food adulteration challenges.

Dual-template magnetic molecularly imprinted polymers for selective extraction and sensitive detection of aflatoxin B1 and benzo(α)pyrene in environmental water and edible oil

The coexistence of multiple contaminates in the environment and food is of growing concern due to their extremely hazard as a well-known class I carcinogen, like aflatoxin B1 (AFB1) and benzo(α)pyrene (BaP). AFB1 and BaP are susceptible to coexistence in environmental water and edible oil, posing a significant potential risk to environmental monitoring and food safety. The remaining challenges in detecting multiple contaminates include unsatisfied sensitivity, insufficient targets selectivity, and interferences in complex matrices. Here, we developed dual-template magnetic molecularly imprinted polymers (DMMIPs) for selective extraction of dual targets in complex matrices from the environment and food. The DMMIPs were fabricated by surface imprinting with vinyl-functionalized Fe3O4 as carrier, 5,7-dimethoxycoumarin and pyrene as dummy templates, and methacrylamide as functional monomer. The DMMIPs showed excellent adsorption ability (12.73-15.80 mg/g), imprinting factors (2.01-2.58), and reusability of three adsorption-desorption cycles for AFB1 and BaP. The adsorption mechanism including hydrogen bond, electrostatic interaction and van der Waals force was confirmed by physical characterization and DFT calculation. Applying DMMIPs in magnetic solid phase extraction (MSPE) followed by high-performance liquid chromatography (HPLC) analysis enabled detection limits of 0.134 μg/L for AFB1 and 0.107 μg/L for BaP. Recovery rates for water and edible oil samples were recorded as 86.2%-110.3% with RSDs of 4.1%-11.9%. This approach demonstrates potential for simultaneous identification and extraction of multiple contaminants in environmental and food.

Investigation of low-temperature partitioning with dispersive solid-phase extraction for quantification of pesticides in apples followed by electrospray-ionization mobility spectrometry: Comparison with conventional procedure

Ion mobility spectrometry (IMS) has a promising application prospect in food surveillance. However, due to the complexity of food matrix and trace levels of pesticide residues, the effective and rapid detection of pesticides by IMS has been a challenge, especially when using electrospray ionization (ESI) as an ion source. In this study, low-temperature partitioning with dispersive solid-phase extraction (LTP-dSPE) was explored and compared with conventional procedures. Both methods were validated for the quantification of eight pesticides in apples, obtaining a limit of detection (LOD) of 0.02-0.12 mg/kg for LTP-dSPE and 0.02-0.09 mg/kg for conventional solid-phase extraction (SPE), lower than those usually stipulated by government legislation in food matrices. For LTP-dSPE, the matrx effect (ME) ranged from -16.3 to -68.6 %, lower than that for the SPE method, ranging from -70.0 to -92.9 %. The results showed satisfactory efficiency and precision, with recovery values ranging from 67.9 to 115.4 % for LTP-dSPE and from 62.0 to 114.8 % for conventional SPE, with relative standard deviations below 13.0 %. Notably, the proposed LTP-dSPE/ESI-IMS has been shown to be more cost-effective, easier to use, more environment-friendly, more accessible, and, most importantly, less matrix effect than the conventional method, thereby being suitably applicable to a wide range of food safety applications.

Magnetic solid phase extraction coupled to HPLC-UV for highly sensitive analysis of mono-hydroxy polycyclic aromatic hydrocarbons in urine

BACKGROUND

As a common pollutant, the carcinogenic properties of polycyclic aromatic hydrocarbons have garnered considerable attention. Trace metabolites of polycyclic aromatic hydrocarbons can be detected in urine as a non-invasively approach to monitor the exposure level. Nonetheless, the urine samples have the disadvantages of being large in volume and containing numerous impurities. Given the growing demand to study metabolites with low abundance and potential biomarkers, there is a pressing need for a preconcentration and high-throughput technique for effectively handling complex liquid samples.

RESULTS

Polystyrene-coated magnetic nanoparticles were used to establish a novel magnetic extraction method for monohydroxy polycyclic aromatic hydrocarbons in urine samples. Polystyrene magnetic nanoparticles are an ideal absorbent for solid-phase extraction. After the material was mixed with the sample and adsorbed the target analyte, the analytes on the material were eluted and quantified using high-performance liquid chromatography. Influencing factors were optimized, and the proposed method achieved desirable sensitivity in analyzing low-abundance metabolites in large volumes of complex urine samples. The recoveries of intra-day and inter-day were 78.0-118.0 % and 81.0 %-115.0 %, respectively. The intra-day and inter-day reproducibility were less than 4.5 % and 8.6 %, respectively. The limits of detection were in the range of 0.009-0.041 ng mL-1, and the limits of quantification were in the range of 0.030-0.135 ng mL-1.

SIGNIFICANCE AND NOVELTY

The application of reusable polystyrene-coated magnetic solid-phase nanoparticles as adsorbents makes the extraction of monohydroxy polycyclic aromatic hydrocarbons from urine samples economical and environmentally benign. The proposed method is simple, sensitive, and efficient compared to existing techniques. The nanoparticles are easy to prepare, showing potential for rapid screening of complex bulk bio-samples in batches with high efficiency and low budget.

Magnetic nanoparticle-based immunosensors and aptasensors for mycotoxin detection in foodstuffs: An update

Mycotoxin contamination of food crops is a global challenge due to their unpredictable occurrence and severe adverse health effects on humans. Therefore, it is of great importance to develop effective tools to prevent the accumulation of mycotoxins through the food chain. The use of magnetic nanoparticle (MNP)-assisted biosensors for detecting mycotoxin in complex foodstuffs has garnered great interest due to the significantly enhanced sensitivity and accuracy. Within such a context, this review includes the fundamentals and recent advances (2020-2023) in the area of mycotoxin monitoring in food matrices using MNP-based aptasensors and immunosensors. In this review, we start by providing a comprehensive introduction to the design of immunosensors (natural antibody or nanobody, random or site-oriented immobilization) and aptasensors (techniques for aptamer selection, characterization, and truncation). Meanwhile, special attention is paid to the multifunctionalities of MNPs (recoverable adsorbent, versatile carrier, and signal indicator) in preparing mycotoxin-specific biosensors. Further, the contribution of MNPs to the multiplexing determination of various mycotoxins is summarized. Finally, challenges and future perspectives for the practical applications of MNP-assisted biosensors are also discussed. The progress and updates of MNP-based biosensors shown in this review are expected to offer readers valuable insights about the design of MNP-based tools for the effective detection of mycotoxins in practical applications.

Determination of multi-mycotoxins in vegetable oil via liquid chromatography-high resolution mass spectrometry assisted by a complementary liquid-liquid extraction

The simultaneous determination of multi-mycotoxins in food commodities are highly desirable due to their potential toxic effects and mass consumption of foods. Herein, liquid chromatography-quadrupole exactive orbitrap mass spectrometry was proposed to analyze multi-mycotoxins in commercial vegetable oils. Specifically, the method featured a successive liquid-liquid extraction process, in which the complementary solvents consisted of acetonitrile and water were optimized. Resultantly, matrix effects were reduced greatly. External calibration approach revealed good quantification property for each analyte. Under optimal conditions, the recovery ranging from 80.8% to 109.7%, relative standard deviation less than 11.7%, and good limit of quantification (0.35 to 45.4 ng/g) were achieved. The high accuracy of proposed method was also validated. The detection of 20 commercial vegetable oils revealed that aflatoxins B1 and B2, zearalenone were observed in 10 real samples. The as-developed method is simple and low-cost, which merits the wide applications for scanning mycotoxins in oil matrices.

Mycotoxins in Vegetable Oils: A Review of Recent Developments, Current Challenges and Future Perspectives in Sample Preparation, Chromatographic Determination, and Analysis of Real Samples

Mycotoxins are toxic compounds that are formed as secondary metabolites by some fungal species that contaminate crops during pre- and postharvest stages. Exposure to mycotoxins can lead to adverse health effects in humans, such as carcinogenicity, mutagenicity, and teratogenicity. Hence, there is a need to develop analytical methods for their determination in vegetable oils that possess high sensitivity and selectivity. In the current review (116 references), the recent developments, current challenges, and perspectives in sample preparation techniques and chromatographic determination are summarized. It is impressive that current sample preparation techniques such as dispersive liquid-liquid microextraction (DLLME), quick, easy, cheap, rugged, and safe method (QuEChERS) and solid phase extraction (SPE) have exhibited high extraction recoveries and minimal matrix effects. However, a few studies have reported signal suppression or enhancement. Regarding chromatographic techniques, high sensitivity and selectivity have been reported by liquid chromatography coupled to fluorescence detection, tandem mass spectrometry, or high-resolution mass spectrometry. Furthermore, current challenges and perspectives in this field are tentatively proposed.

Rapid and Sensitive Detection of Polycyclic Aromatic Hydrocarbons in Tea Leaves Using Magnetic Approach

A rapid and efficient method using an alkyl-functionalized magnetic nanoparticles-based extraction technique combined with Ultra-High Performance Liquid Chromatography was developed for the detection of trace amounts of polycyclic aromatic hydrocarbons in tea leaves. As a popular coating for chromatographic column packing materials, C₁₈-alkyl has been demonstrated to be effective in separating polycyclic aromatic hydrocarbons. Additionally, the magnetism of the nanomaterials accelerates the extraction process while their high surface ratio enables desirable dispersity in the sample matrix. Meanwhile, the adsorbents can be washed and reused 30 times without compromising recovery, which greatly reduces the budget. The effects of various parameters were investigated and optimized, and the recoveries for five analytes were in the range of 84.8-105.4%. The RSD of intra-day and inter-day were below 11.9% and 6.8%, respectively. The limits of detection and limits of quantification ranged from 1.69-9.97 ng g^-1 and 5.12-30.21 ng g^-1, indicating satisfactory sensitivity. Thus, the proposed methodology is rapid, highly efficient, and economical, and it expands the application of magnetic cleanup approaches in complex food matrices.

A global systematic review and meta-analysis on prevalence of the aflatoxin B1 contamination in olive oil

Olive oil can be contaminated by fungal toxins; therefore, it is necessary to monitor the incidence of mycotoxins in this oil. In the present study, the pooled prevalence of detectable aflatoxin B₁ (AFB₁) in olive oil was evaluated using systematic review and meta-analysis approach from 1 January 1991 to 31 December 2020 (30 years study). The search was conducted via electronic databases involving Scopus, Web of Science, PubMed, Agris and Agricola. Synonyms were collected from combination of the MESH, Agrovoc and free text method. After screening and selection process of primary researches, full texts of eligible researches (46 studies) were evaluated and data of the nine studies as included researches were extracted. Random effect model was used to estimate the pooled prevalence of AFB₁ in olive oil and weighing model of Dersimonian-Laired was applied. Summary measure of mycotoxin prevalence was estimated using Metaprop module of STATA and 95% confidence interval (CI) were calculated using the Binomial Exact Method. Pooled prevalence of AFB₁ in olive oils were 32% (95% CI 8-56%) which means that 68% of olive oil were free of detectable contaminants of AFB₁. Due to controversy over the results of primary studies, future researches and consequent subgroup analysis based on the main variables affecting the aflatoxins contamination in olive oil are recommended to achieve the conclusive results.

Recent Progress on Techniques in the Detection of Aflatoxin B1 in Edible Oil: A Mini Review

Contamination of agricultural products and foods by aflatoxin B1 (AFB1) is becoming a serious global problem, and the presence of AFB1 in edible oil is frequent and has become inevitable, especially in underdeveloped countries and regions. As AFB1 results from a possible degradation of aflatoxins and the interaction of the resulting toxic compound with food components, it could cause chronic disease or severe cancers, increasing morbidity and mortality. Therefore, rapid and reliable detection methods are essential for checking AFB1 occurrence in foodstuffs to ensure food safety. Recently, new biosensor technologies have become a research hotspot due to their characteristics of speed and accuracy. This review describes various technologies such as chromatographic and spectroscopic techniques, ELISA techniques, and biosensing techniques, along with their advantages and weaknesses, for AFB1 control in edible oil and provides new insight into AFB1 detection for future work. Although compared with other technologies, biosensor technology involves the cross integration of multiple technologies, such as spectral technology and new nano materials, and has great potential, some challenges regarding their stability, cost, etc., need further studies.

Surfactant-Enhanced and Automated Pretreatment Based on Immunoaffinity Magnetic Beads Coupled with Ultra-Performance Liquid Chromatography with Fluorescence Detection for the Determination of Aflatoxins in Peanut Oils

Sample pretreatment is an important step in the detection and analysis of mycotoxins. However, conventional pretreatment methods are complex, time-consuming, and labor-intensive; moreover, they generate a large amount of organic waste that pollutes the environment. An environmentally friendly and automated pretreatment method is proposed. Without extraction using organic solvents in advance, aflatoxins in peanut oil are directly cleaned and concentrated by immunomagnetic beads with the aid of a reaction solution containing surfactant Tween-20. Under optimal conditions, the proposed pretreatment method requires 40 min to simultaneously pretreat 10-24 samples without any centrifugation or filtering steps, and virtually no organic waste was produced. This pretreatment step was coupled with ultra-performance liquid chromatography-fluorescence detection to develop an effective detection method. The recovery of spiked aflatoxins in peanut oils at different concentrations ranged from 91.6 to 100.8%, and the relative standard deviation was below 5.3%. This reliable method overcomes the drawbacks of conventional methods and offers great application prospects.

Risk Assessment of Hepatocellular Carcinoma with Aflatoxin B1 Exposure in Edible Oils

Contamination of edible oils with aflatoxins (AFs) is a universal issue due to the detrimental effects of aflatoxins on human health and the fact that edible oils are a major source of fungal growth, particularly storage fungi (Aspergillus sp.). The objective of this study was to assess aflatoxin B1 (AFB1) in edible oil used in fried food in order to determine the risk of cancer from AFB1 exposure through cooked food using the FAO/WHO’s and EFSA’s margin of exposure (MOE) quantitative liver cancer risk approaches. Using Mycosep 226 columns and HPLC-FLD, 100 samples of cooking oils (soybean, canola, and sunflower oil) from different food points were analyzed for contamination with aflatoxins. Of all the samples tested, 89% were positive for total aflatoxins and AFB1, with 65% indicating AF concentrations beyond permitted levels. Canola oil was found to contain higher levels of AFB1 and AFs than soybean and sunflower oil. Almost 71 percent of canola oil samples (range of 54.4–281.1 µg/kg) were contaminated with AF levels higher than the proposed limits of the European Union (20 µg/kg). The consumption of canola oil samples used in fried foods had MOE values that were significantly lower as compared to sunflower and soybean oils, indicating that risk reduction is feasible. Additionally, compared to soybean and sunflower oil, canola oil exhibited a greater threat of liver cancer cases linked to AFB1 exposure (17.13 per 100,000 males over 35 and 10.93 per 100,000 females over 35). Using a quantitative liver cancer approach, health risk valuation demonstrated that males and females over the age of 35 are at significant risk of developing liver cancer. The health risk assessment exposed that the males and female over the age of 35 are at considerable risk of liver cancer by using a quantitative liver cancer approach. The innovation of this study lies in the fact that no such study is reported related to liver cancer risk evaluation accompanied with AFB1 exposure from consumed edible oil. As a result, a national strategy must be developed to solve this problem so that edible oil products are subjected to severe regulatory examination.

Recent Advances on the Function and Purification of Milk Exosomes: A Review

Exosomes are nano-scale extracellular vesicles, which can be used as drug carriers, tumor treatment, intestinal development and immune regulator. That is why it has great potential in pharmacy, functional foods, nutritional supplements, especially those for infants, postoperative patients, chemotherapy patients and the elderly. In addition, abnormal exosome level is also related to diseases such as cardiovascular diseases, tumor, diabetes, neurodegenerative and autoimmune diseases, as well as infectious diseases. Despite its high biological significance, pharmaceutical and nutritional value, the low abundancy of exosomes in milk is one of the bottlenecks restricting its in-depth research and real-life application. At present, there is no unified standard for the extraction of breast milk exosomes. Therefore, choosing the proper extraction method is very critical for its subsequent research and development. Based on this, this paper reviewed the purification techniques, the function and the possible applications of milk exosomes based on 47 latest references. Humble advices on future directions, prospects on new ideas and methods which are useful for the study of exosomes are proposed at the end of the paper as well.

Application of Nanomaterials for Coping with Mycotoxin Contamination in Food Safety: From Detection to Control

Mycotoxins, which are toxic secondary metabolites produced by fungi, are harmful to humans. Mycotoxin-induced contamination has drawn attention worldwide. Consequently, the development of reliable and sensitive detection methods and high-efficiency control strategies for mycotoxins is important to safeguard food industry safety and public health. With the rapid development of nanotechnology, many novel nanomaterials that provide tremendous opportunities for greatly improving the detection and control performance of mycotoxins because of their unique properties have emerged. This review comprehensively summarizes recent trends in the application of nanomaterials for detecting mycotoxins (fluorescence, colorimetric, surface-enhanced Raman scattering, electrochemical, and point-of-care testing) and controlling mycotoxins (inhibition of fungal growth, mycotoxin absorption, and degradation). These detection methods possess the advantages of high sensitivity and selectivity, operational simplicity, and rapidity. With research attention on the control of mycotoxins and the gradual excavation of the properties of nanomaterials, nanomaterials are also employed for the inhibition of fungal growth, mycotoxin absorption, and mycotoxin degradation, and impressive controlling effects are obtained. This review is expected to provide the readers insight into this state-of-the-art area and a reference to design nanomaterials-based schemes for the detection and control of mycotoxins.

Effects of Air Frying on French Fries: The Indication Role of Physicochemical Properties on the Formation of Maillard Hazards, and the Changes of Starch Digestibility

This study focused on the formation of Maillard hazards in air fried fries, highlighting the correlation between the resultant physical properties of the fries and the formation of Maillard hazards. In the meantime, the effects of air frying on the in vitro starch digestibility of fries were explored. Potato strips were fried at various temperatures (180-200°C) and time (12-24 min). Results indicated that the extent of browning, hardness, and the contents of Maillard hazards (acrylamide, 5-hydroxymethylfurfural, methylglyoxal, and glyoxal) all increased steadily with air frying temperature and time. Moisture content were negatively correlated (p < 0.001) with Maillard hazards content and physicochemical properties except for L^* with the correlation coefficients range from -0.53 to 0.94, and positively correlated with L^* value with correlation coefficient was 0.91, hence, reducing the Maillard hazard exposure while maintaining the desired product quality can be achieved by controlling the moisture content of the air fried French fries. Compared with deep frying (180°C-6 min), air frying decreased acrylamide and 5-hydroxymethylfurfural content with the maximum reduction rate were 47.31 and 57.04%, respectively. In addition, the in vitro digestion results suggested that air frying resulted in higher levels of slowly digestible starch (48.54-58.42%) and lower levels of resistant starch (20.08-29.34%) as compared to those from deep frying (45.59 ± 4.89 and 35.22 ± 0.65%, respectively), which might contribute to more balanced blood sugar levels after consumption. Based on the above results, it was concluded that air frying can reduce the formation of food hazards and was relatively healthier.

Solid-phase extraction techniques based on nanomaterials for mycotoxin analysis: An overview for food and agricultural products

Mycotoxin contamination is a globally concerned problem for food and agricultural products since it may directly or indirectly induce severe threats to human health. Sensitive and selective screening is an efficient strategy to prevent or reduce human and animal exposure to mycotoxins. However, enormous challenges exist in the determination of mycotoxins, arising from complex sample matrices, trace-level analytes, and the co-occurrence of diverse mycotoxins. Appropriate sample preparation is essential to isolate, purify, and enrich mycotoxins from complicated matrices, thus decreasing sample matrix effects and lowering detection limits. With the cross-disciplinary development, new solid-phase extraction strategies have been exploited and integrated with nanotechnology to meet the challenges of mycotoxin analysis. This review summarizes the advance and progress of solid-phase extraction techniques as the methodological solutions for mycotoxin analysis. Emphases are paid on nanomaterials fabricated as trapping media of SPE techniques, including carbonaceous nanoparticles, metal/metal oxide-based nanoparticles, and nanoporous materials. Advantages and limitations are discussed, along with the potential prospects. This article is protected by copyright. All rights reserved.

Rapid Determination of Vitamin D3 in Aquatic Products by Polypyrrole-Coated Magnetic Nanoparticles Extraction Coupled with High-Performance Liquid Chromatography Detection

A method using polypyrrole-coated Fe₃O₄ (Fe₃O₄@PPy composites) based extraction coupled with high performance liquid chromatography was developed for adsorption and detection of trace vitamin D₃ (VD₃) in aquatic products. The fabricated Fe₃O₄@PPy composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Fe₃O₄@PPy composites showed efficient adsorption of VD₃ at pH 9.0 and 25 °C with a dose of 25 mg per 10 mL of sample solution and an adsorption time of 11 min. Methanol was selected as the desorption solvent to recover VD₃ from Fe₃O₄@PPy composites after 3 min of static treatment. Fe₃O₄@PPy composites can be used for VD₃ adsorption at least two times. The developed method showed a good linearity for VD₃ determination in the range of 0.1-10 μg/mL with a correlation coefficient of 0.9989. The limits of detection and quantification were 10 ng/mL and 33 ng/mL, respectively. The recovery of VD₃ in a spiking test was 97.72% with a relative standard deviation value of 1.78%. The content of VD₃ in nine aquatic products was determined with this method. Our results show that Fe₃O₄@PPy composites provide a convenient method for the adsorption and determination of VD₃ from the complex matrix of aquatic products.

A highly sensitive ratiometric fluorescent sensor for copper ions and cadmium ions in scallops based on nitrogen doped graphene quantum dots cooperating with gold nanoclusters

Based on the electrostatic interaction, we constructed a ratiometric fluorescence nanomixture of graphene quantum dots-gold nanoclusters (GQDs-AuNCs) for the quantitative detection of Cu²⁺ and Cd²⁺. When Cu²⁺ or Cd²⁺ was added into the reaction system, the fluorescence of GSH-AuNCs at 565 nm can be quenched by Cu²⁺ and enhanced by Cd²⁺ while the intensity of N-GQDs at 403 nm stayed constant. Under the optimized conditions, the fluorescence intensity ratio (I₅₆₅/I₄₀₃) of the GQDs-AuNCs system was proportional to the concentration of Cu²⁺ and Cd²⁺ in the range of 8×10^-8 mol/L-6×10^-6 mol/L and 1×10^-6 mol/L-4×10^-5 mol/L, respectively, with detection limits of 4.12×10^-9 mol/L and 9.43×10^-7 mol/L, respectively. In the presence of Cu²⁺ and Cd²⁺, the paper-based vision sensor would produce visible fluorescent color changes, which can be used for rapid detection on site. The method has been successfully applied to the determination of Cu²⁺ and Cd²⁺ in scallops with satisfactory results.

Design, Preparation, and Application of Magnetic Nanoparticles for Food Safety Analysis: A Review of Recent Advances

This review (with 126 references) aims at providing an updated overview of the recent developments and innovations of the preparation and application of magnetic nanoparticles for food safety analysis. During the past two decades, various magnetic nanoparticles with different sizes, shapes, and surface modifications have been designed, synthesized, and characterized with the prospering development of material science. Analytical scientists and food scientists are among the ones who bring these novel materials from laboratories to commercial applications. Powerful and versatile surface functional groups and high surface to mass ratios make these magnetic nanoparticles useful tools for high-efficiency capture and preconcentration of certain molecules, even when they exist in trace levels or complicated food matrices. This is why more and more methods for sensitive detection and quantification of hazards in foods are developed based on these magic magnetic tools. In this review, the principles and superiorities of using magnetic nanoparticles for food pollutant analysis are first introduced, like the mechanism of magnetic solid phase extraction, a most commonly used method for food safety-related sample pretreatment. Their design and preparation are presented afterward, alongside the mechanisms underlying their application for different analytical purposes. After that, recently developed magnetic nanoparticle-based methods for dealing with food pollutants such as organic pollutants, heavy metals, and pathogens in different food matrices are summarized in detail. In the end, some humble outlooks on future directions for work in this field are provided.

The selective recognition mechanism of a novel highly hydrophobic ion-imprinted polymer towards Cd(ii) and its application in edible vegetable oil

Edible vegetable oils are easily contaminated by heavy metals, resulting in the oxidative degradation of oils and various health effects on humans. Therefore, it is very important to develop a rapid and efficient method to extract trace heavy metals from vegetable oils. In this work, a highly hydrophobic ion-imprinted polymer (IIP) was synthesized on a novel raspberry (RS)-like particle surface. The synthesized IIP@RS was characterized and used in solid-phase extraction (SPE) for the selective and fast adsorption of Cd(ii) from vegetable oils. The results showed that IIP was successfully coated onto RS particles with a high specific surface area (458.7 m² g⁻¹) and uniform porous structure. The contact angle (θ) value (141.8°) of IIP@RS was close to the critical value of super-hydrophobic materials, which is beneficial to their adsorption in hydrophobic vegetable oils. The IIP@RS also exhibited excellent adsorption ability and selectivity to Cd(ii) with a maximum adsorption capacity of 36.62 mg g⁻¹, imprinting factor of 4.31 and equilibrium adsorption rate of 30 min. According to isothermal titration calorimetry results, the recognition behavior of IIP@RS for Cd(ii) was mainly contributed by Cd(ii)-induced cavities during gel formation and coordination between Cd(ii) and –SH groups in imprinted cavities. Furthermore, the adsorption process driven by entropy and enthalpy was spontaneous at all temperatures. In real vegetable oil samples, IIP@RS-SPE adsorbed approximately 96.5–115.8% of Cd(ii) with a detection limit of 0.62 μg L⁻¹. Therefore, IIP@RS has wide application prospects in enriching and detecting Cd(ii) from vegetable oil.

Edible vegetable oils are easily contaminated by heavy metals, resulting in the oxidative degradation of oils and various health effects on humans.

Recognizing adsorption of Cd(Ⅱ) by a novel core-shell mesoporous ion-imprinted polymer: Characterization, binding mechanism and practical application

A novel monodispersed Cd(II) ion-imprinted polymer (IIP) was synthesized inside core-shell mesoporous silica (C-SMS) particles to improve the diffusion kinetics of the polymer. The synthesized IIP@C-SMS was characterized and subsequently used in solid-phase extraction (SPE) for the selective adsorption of Cd(II) in aquatic samples. The results indicated that IIP had been successfully assembled inside the C-SMS particles with a high specific surface area (546.3 m² g^-1) and uniform mesoporous size (2.07 nm). The obtained IIP@C-SMS takes only 15 min to reach the adsorption equilibrium due to the highly developed mesoporous structure. IIP@C-SMS also presented a maximal adsorption capacity (201.9 μmol g^-1) for Cd(II), which was much higher than that of NIP@C-SMS (80.3 μmol g^-1). The relative selectivity coefficient of IIP@C-SMS for Cd(II)/M(II) (M = Cu(II), Pb(II), Cr(II), and Ni(II)) were 7.15, 8.70, 7.18, and 7.36, respectively, further confirming the satisfactory selectivity of IIP@C-SMS. The adsorption isotherms of IIP@C-SMS toward Cd(II) could be described by Langmuir model; whereas the adsorption kinetics could be fitted by the pseudo-second-order model, indicating chemisorption was the rate-limiting step. The FT-IR, ITC and XPS analysis further confirmed that the Cd(II)-induced cavities during the ion-imprinting process and the coordination between Cd(II) and -SH groups were the main adsorption mechanism. Furthermore, in real samples, IIP@C-SMS-SPE adsorbed approximately 93-104% of Cd(II). This work provides new insights for the design of novel macroporous sorbents for Cd(II).

Contrastive analysis of lipid composition and thermal and crystallization behavior of olein/stearin fractionated by novel layer melt crystallization from palm oil

BACKGROUND

Melt crystallization is typically recognized as a highly efficient and green method for oil fractionation. This work concentrated on novel layer melt crystallization for preparing desirable olein and stearin products from palm oil and the evaluation of fraction quality. Layer melt crystallization was performed at various temperatures and the effects on fractions were evaluated using iodine value (IV), solid fat content (SFC) and melting point. The lipid composition, thermal and crystallization properties, and phase behaviors of the final optimized fractions were determined using gas chromatography, high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry and differential scanning calorimetry.

RESULTS

Increasing crystallization tube temperatures under the same jacket temperature increased the melting point and SFC, while decreasing the IV of the olein product. Opposite results were observed for the stearin product. Major fatty acids in fractions were determined as palmitic acid and oleic acid. 1,2-Dioleoyl-3-palmitoylglycerol and 1,3-dipalmitoyl-2-oleoylglycerol were identified as the main triacylglycerols in olein and stearin fractions, respectively. A critical effect of crystallization temperature on co-crystallization of oleins and stearins was revealed. A transition from plate-like crystal growth to spherulitic growth with spontaneous nucleation was indicated in palm oil and stearin fractions with increasing crystallization temperature. As for olein fractions, a temperature increase resulted in heterogeneous nucleation from instantaneous nucleation.

CONCLUSIONS

Novel layer melt crystallization was successfully applied and optimized for fractionating palm oil. The composition and property changes of obtained fractions were analyzed and explained at both macroscopic and microscopic levels. © 2021 Society of Chemical Industry.

Size-exclusion chromatography selective cleanup of aflatoxins in oilseeds followed by HPLC determination to assess the potential health risk

Aflatoxins (AFs) are one of the most harmful carcinogenic natural toxins that affect food. Crops containing reasonably high oil content may be affected by Aspergillus species and consequently by AF contamination. In this study, a proposed testing method for AF detection in oilseed was developed, validated, and used for a market survey to assess the probabilistic risk exposure caused by consuming contaminated oilseeds including corn, sunflower seed, and soybean. The test method was optimized for selective extraction and then validated for fitness of purpose; the limits of quantification (LOQs) were 0.2, 0.4, 0.2, and 0.2 μg kg^-1 for aflatoxin G1 (AFG1), aflatoxin B1 (AFB1), aflatoxin G2 (AFG2), and aflatoxin B2 (AFB2), respectively. The method was linear from the LOQs up to 20 μg kg^-1, and its budget of measurement uncertainties were estimated at 25, 24, 26, and 30 for AFG1, AFB1, AFG2, and AFB2, respectively. The contamination levels were from <LOQ to 2.65 μg kg^-1 and from <LOQ to 26.9 μg kg^-1 for corn and sunflower oilseed samples, respectively, whereas the soybean samples were AF-free. According to the consumption rate of corn and sunflower seeds, the estimated margins of exposure to AFB1 were 721 and > 10,000 body weight (BW) day^-1, respectively. The main finding of the present study highlights the possibility of some risk of AF exposure from corn consumption, which may represent a health concern.

Metal-organic framework for the extraction and detection of pesticides from food commodities

Pesticide residues in food matrices, threatening the survival and development of humanity, is one of the critical challenges worldwide. Metal-organic frameworks (MOFs) possess excellent properties, which include excellent adsorption capacity, tailorable shape and size, hierarchical structure, numerous surface-active sites, high specific surface areas, high chemical stabilities, and ease of modification and functionalization. These promising properties render MOFs as advantageous porous materials for the extraction and detection of pesticides in food samples. This review is based on a brief introduction of MOFs and highlights recent advances in pesticide extraction and detection through MOFs. Furthermore, the challenges and prospects in this field are also described.

Magnetic hollow bimetallic zinc/cobalt zeolitic imidazolate framework as sorbent for efficiently enriching aflatoxins combined with UHPLC-IT-MSn determination

A novel magnetic hollow bimetallic zinc/cobalt-based zeolitic imidazolate framework (MHB-Zn/Co-ZIF-8) was prepared via a microwave-assisted chemical etching in methanol. The structure, morphology, and specific surface area were characterized by X-ray diffraction and FTIR spectroscopy, scanning and transmission electron microscopy, and N₂ adsorption. The hollow nanostructures with high internal specific surface area, abundant active sites, and reduced aggregation of nanoparticles endow the hollow zeolitic imidazolate framework (ZIF) nanoparticle with high chemical stability, desirable durability, and excellent adsorption abilities. The MHB-Zn/Co-ZIF-8 nanoparticle was used as an effective sorbent for magnetic solid-phase extraction (MSPE) of trace aflatoxins B₁, B₂, G₁, and G₂ from fruit juice and fruit samples. The main parameters affecting the efficiency of MSPE procedures were investigated and optimized. The results show that, under optimized conditions, enrichment factors ranging from 67- to 355-fold are obtained for the target analytes. The method is linear in the range 1.0 to 100.0 ng mL^-1 with correlation coefficients (R²) from 0.9960 to 0.9992. The limits of detection of four aflatoxins are in the range 0.18 to 1.50 ng mL^-1 and the average recoveries range from 75.1 to 102.4%, with relative standard deviations (RSDs) less than 13.6%. This work presents the excellent extraction performance of aflatoxins B₁, B₂, G₁, and G₂ on MHB-Zn/Co-ZIF-8. In addition, the applicability of the MSPE coupling with ultrahigh-performance liquid chromatography-ion trap tandem mass spectrometry (UHPLC-IT-MSⁿ) for trace analysis in complex matrices is shown. Graphical abstract Schematic presentation of magnetic hollow bimetallic zinc/cobalt zeolitic imidazolate framework as sorbent for efficiently enriching aflatoxins B₁, B₂, G₁, and G₂ from fruit juice samples prior to ultrahigh-performance liquid chromatography-ion trap tandem mass spectrometry (UHPLC-IT-MSⁿ) determination.

Dietary Intake of Mycotoxin Susceptible Foods by Brazilian Nursing Mothers

Background:

The human milk has several health benefits to the mother and child, and it is the ideal form of nutrition for infants. However, some food contaminants such as mycotoxins can be transferred from the mother to the child through breast milk.

Objective:

To access the dietary intake of mycotoxin susceptible foods by nursing mothers.

Methods:

The dietary intake of mycotoxin susceptible foods was investigated by interviewing nursing mothers (n = 86), who were registered donors of the Human Milk Bank (HMB) of Blumenau (Brazil), through a food frequency questionnaire (FFQ). The mothers were contacted and those who agreed to answer the FFQ were recruited for the study group. The interview was conducted individually, face to face with each mother, by a trained researcher. The FFQ was divided into three food Groups (vegetables, animal and beverages, respectively), considered most prone to mycotoxins contamination. Socio-demographic characteristics of the mothers were also obtained.

Results:

The FFQ revealed a high weekly intake of foods susceptible to fungi and mycotoxin contamination. Consumption of wheat, coffee and cow’s milk was reported by 52, 44 and 51% of the mothers, respectively. The consumption of those foods occurred daily to more than 7 times per week.

Conclusion:

The study revealed that Brazilian nursing mothers frequently consume foods susceptible to mycotoxin contamination, especially wheat and its by-products. Brazilian health, environmental and agriculture authorities should pay permanent attention by applying monitoring programs to grains and cereals - both imported and domestically produced - as they are highly susceptible to fungi and mycotoxin contamination, which can be transferred to infants via breastfeeding, apart from harming the general population health.