Food Samples Research Articles

Two-Dimensional TiS2 Nanosheet- and Conjugated Polymer Nanoparticle-Based Composites for Sensing Applications.

The assessment of phenolic compounds in food samples, environmental samples, and medical applications has gained importance recently. Here, we present research on novel conjugated polymer nanoparticles (P-PimBzBt NPs) and their composites with two-dimensional titanium disulfide nanosheets (2D-TiS2) for electrochemical tyrosinase (TYR)-based catechol detection. P-PimBzBt NPs are decorated with 2D-TiS2 to enhance the electrochemical performance for biosensing. In addition, the interaction of P-PimBzBt NPs with TiS2 was investigated at the molecular level by employing van der Waals (vdW) dispersion-corrected density functional theory (DFT) calculations and classical all-atom molecular dynamics simulations. According to the theoretical studies, the presence of the TiS2 layer increases the interfacial interaction with the conjugated polymer via electrostatic interactions. Using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) analyses, the production of SPE/TiS2@P-PimBzBt NPs/TYR nanobiosensors was examined. With a detection range of 3.0-27.5 μM, 0.33 μM LOD, and 3.89 μA/μM·cm2 sensitivity values, the sensing layer based on the TiS2@P-PimBzBt NP composites has a targeting ability toward catechol. Its selectivity was investigated using commonly used interfering ions and compounds such as citric acid, urea, glucose, uric acid, KCl, and NaCl. Application of nanobiosensors to actual samples (tap water and black tea) was carried out with high accuracy. The fabricated biosensing platform demonstrates that P-PimBzBt NPs with 2D-TiS2 nanomaterial functionalization are appropriate as electrode materials and could be used to create an inexpensive, fast-response, and highly selective electrochemical biosensor for the detection of catechol in actual samples.

MOF-mediated cascade reaction system for ultrasensitive detection of alkaline phosphatase activity and organophosphorus pesticides.

Ametal-organic-framework (MOF) fluorescent sensor is reportedbased on NH2-MIL-101(Fe) propelled pesticide and alkaline phosphatase (ALP) catalytic reaction. Different from previous reports, a cascade reaction system combined with MOF structural changes to generate fluorescence was employed. The rationale is that ALP can hydrolyze L-ascorbic acid 2-phosphate (AAP) into L-ascorbic acid (AA), which can reduce Fe3+ to decompose structurally NH2-MIL-101(Fe), resulting in 2-aminoterephthalic acid (NH2-BDC) with intense fluorescence. The fluorescence can be decreased to different degrees due to inhibition of organophosphate pesticides (OPPs) on the activity of ALP. By taking chlorpyrifos (CPY) as the model compoundof anOPP pesticide and adding ALP and CPY into the NH2-MIL-101(Fe) framework, the resulting cascade reaction fluorescence sensors exhibit a good sensitivity for CPY and ALP sensing. The working ranges are 0.02-2 μg/L and 0.2-20 mU/mL with detection limits (LOD) of 5.31 ng/L and 0.05 mU/mL, respectively. The proposed sensor has been actually applied tosatisfactory detection of CPY and ALP in food and serum samples. This fluorescence-based assay may extend the application of MOF-based biosensors.

A novel approach based on supramolecular solvents microextraction for quick detection of perfluoroalkyl acids and their precursors in aquatic food

Per-and polyfluoroalkyl substances (PFASs) have garnered significant attention owing to their prevalence and adverse effects on humans. The direct dietary intake of perfluoroalkyl acids (PFAAs) and PFAAs precursors (pre-PFAAs) biotransformation are considered major contributors to human exposure to PFASs. However, little information is available on analytical methods for the simultaneous detection of PFAAs and pre-PFAAs. In the present study, a single-step sample-treatment-based supramolecular solvents-dispersed liquid-liquid microextraction (SUPRASs-DLLME) technique was established for the analysis of 16 PFAAs and 7 pre-PFAAs in aquatic food. SUPRASs were synthesized using 1-heptanol (3 mL) and tetrahydrofuran (4 mL), which were self-assembled in water. The parameters for microextraction, such as extraction method and enrichment capacity, were optimized. Under the optimum conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.03–0.15 ng·g−1 and 0.1–0.5 ng·g−1, respectively. Good linearities (R2 > 0.996) were obtained for all the target compounds, and the recoveries ranged 81.1–120 % with relative standard deviations (RSDs) lower than 20 %. This method was applied to the analysis of 16 PFAAs and 7 pre-PFAAs in aquatic food samples (crabs, prawns, and fish). This study provides a new idea for analyzing other pollutants in biological samples.

Characterization and genomic analysis of the lytic bacteriophage vB_EclM_HK6 as a potential approach to biocontrol the spread of Enterobacter cloacae contaminating food

BackgroundIncreased prevalence of Enterobacter cloacae within food products underscores food as an underexplored reservoir for antibiotic resistance, thus requiring particular intervention. Bacteriophages have been explored as a promising approach for controlling bacterial growth in different matrices. Moreover, their specific interaction and self-replication, put them apart from traditional methods for controlling bacteria in different matrices.MethodsSixteen Enterobacter cloacae strains were recovered from raw chicken. These strains were used to isolate bacteriophages using enrichment protocol. The broad-spectrum bacteriophage was evaluated in terms of thermal, pH, shearing stress and storge. Moreover, its infection kinetics, in vitro antibacterial activity, cytotoxicity were also assessed. Genomic sequencing was performed to exclude any potential virulence or resistance genes. Finally, the capability of the isolated phages to control bacterial growth in different chicken samples was assessed alone and in combination with sodium nitrite.ResultsThe lytic bacteriophage vB_EclM_HK6 was isolated and showed the broadest spectrum being able to infect 8/16 E. cloacae strains with a lytic activity against its host strain, E. cloacae EC21, as low as MOI of 10–6. The phage displays a latent period of 10 min and burst size of 115 ± 44 and resistance frequency of 5.7 × 10–4 ± 3.0 × 10–4. Stability assessment revealed a thermal tolerance up to 60 ˚C, wide range pH stability (3–10) and the ability to withstand shearing stress up to 250 rpm. HK6 shows no cytotoxicity against oral epithelial cells up to 1012 PFU/ml. Genomic analysis revealed a Strabovirus with total size of 177,845 bp that is free from known resistance and virulence genes. Finally, HK6 pretreatment of raw chicken, chicken nuggets and ready-made cheese salad shows a reduced bacterial count up to 4.6, 2.96 and 2.81 log-units, respectively. Moreover, combing HK6 with sodium nitrite further improved the antibacterial activity in both raw chicken and chicken nuggets without significant enhancement in case of cheese salad.ConclusionEnterobacter bacteriophage vB_EclM_HK6 presents a safe and effective approach for controlling E. cloacae contaminating stored chicken food samples. Moreover, they could be combined with a reduced concentrations of sodium nitrite to improve the killing capacity.

CRISPR/Cas12 System-Based Assay for Rapid, Sensitive Detection of Rotavirus in Food Samples.

Foodborne viruses have become an important threat to food safety and human health. Among the foodborne viruses, group A rotavirus is the most important pathogen of diarrhea in autumn and winter. The field detection of rotavirus is crucial for the early control of infection and patient management. Quantitative real-time reverse transcription-polymerase chain reaction is the most widely used in virus detection. However, the technique relies on high-cost instruments and trained personnel, which limit its use in field detection. In this study, we developed accurate, realizable, and simple detection methods by combining optimized CRISPR (clustered regularly interspaced short palindromic repeats) Cas12 and reverse transcription loop-mediated isothermal amplification (RT-LAMP) (reverse transcription loop-mediated isothermal amplification) to reduce the requirements for temperature control and costly real-time fluorescence polymerase chain reaction instruments. We investigated two nucleic acid detection systems combining RT-LAMP with CRISPR Cas12a and RT-LAMP with CRISPR Cas12b and compared them with reverse transcription-quantitative polymerase chain reaction. The resulting detection system only needs a reaction temperature and in single tube to react for 60 min with the detection sensitivity of 38 copies/μL. Overall, this study developed an innovative method for the rapid detection of rotavirus in food samples, which will help to effectively identify food contaminated by pathogens and prevent human infections and economic losses caused by disease outbreaks.

Electrochemical determination of phenolic antioxidant BHT in cosmetic, food and water samples

BHT, an antioxidant often employed in several industries such as food, cosmetics, and food packaging, has raised public health concerns due to its possible toxicological consequences. These concerns originate from both the inherent properties of BHT itself as a result of its usage as an antioxidant. This research presents a novel sensor that uses a combination of a rare lanthanide element and a metal oxide as substrate modifiers on graphene nanopowder. Three independent electrochemical methods, cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy, were used to analyze the electrode modification process. Excellent linearity in the concentration range of 1.0 × 10−12–1.0 × 10−7 M was obtained under the optimal conditions of the technique, with a detection limit of 3.0 × 10−13 M. Repeatability, reproducibility, and stability studies were performed using the proposed sensor. The RSD value for the reproducibility study was 2.91 %. For the within-day repeatability, the repeatability was determined to be 1.97 % for the sensor. After 7 days, the stability studies indicated a decrease up to a value of 90.89 % of the initial value from the first day of assessment.

Carbon‐Nanotube Microelectrodes for Electrochemical Determination of Melatonin

AbstractVoltammetric methods hold promise for the rapid and sensitive quantification of melatonin. This study reports the direct electrochemical quantification of melatonin using carbon nanotube (CNT) fiber cross‐sections as microelectrodes. Six identical highly densified CNT fiber cross‐sections were employed to quantify melatonin in the range of 0.05–100 μM. The limit of detection and quantification were 10 and 35 nM, respectively, with a sensitivity of 0.1322 nA/μM. Interference studies with uric acid, hypoxanthine, and ascorbic acid demonstrate its performance. Real‐world application was highlighted by measuring melatonin in food, pharmaceutical, and human urine samples.

Towards high throughput analysis using 96-well plate solid phase extraction to determine sedatives and β-blocker residues in food control monitoring

BackgroundVeterinary drugs are widely used in animal production to prevent infections and treat diseases but, this may cause a risk to consumers. Due to the high number of food samples required to monitor yearly, simple, fast, sensitive and selective analytical methods are needed in control laboratories to ensure consumers safety. Nevertheless, many analytical methodologies available in these laboratories include multiple steps and therefore are time-consuming and hinder the analysis throughput requiring significant amounts of solvents and reagents. ResultsThis work developed a 96-well plate solid phase extraction (SPE) method for the extraction of seven sedatives and a β-blocker in animal kidney by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC−MS/MS). The developed method was validated based on Implementing Regulation (EU) 2021/808 in kidney, meat and fish. The performance characteristics of the validation (1–5 μg kg−1) showed good linearity (R2 > 0.998) while decision limits (CCα) were between 1 and 1.2 μg kg−1. Trueness and precision were determined at three levels (n = 7) and the results showed values ranging from 85 to 103 % and from 1 to 9 %, respectively. The feasibility of the method was demonstrated for the residue control requirement established by EU. Method was applied to 201 samples of kidney, meat and fish. SignificanceThis study is the first to present an optimized and validated holistic method for sedatives and β-blocker using 96-well plate SPE and UHPLC−MS/MS. The method showed good performance in kidney, meat and fish samples being an universal method for any species along the same type of sample. The fast, easy, efficient, reliable and universal method showed high throughput and so reduced the analysis time by nine-fold and the required solvent amount by four times fulfilling the green chemistry principals.

Amplification-free quantification of Lactiplantibacillus plantarum in food fermentations based on CRISPR/Cas12a with multi-crRNAs

Food fermentations involve numerous microorganisms that are crucial for the quality of the fermented food. Quantifying microorganisms would be beneficial for regulating food fermentations. Recently, clustered regularly interspaced short palindromic repeat (CRISPR)-associated (Cas) systems have emerged as efficient methods for detecting microorganisms. However, it shows great limitations in detection sensitivity and quantitative capability. Herein, we developed a novel amplification-free CRISPR/Cas12a-based quantification method (AFCQ) to effectively quantify Lactiplantibacillus plantarum by adding multiple crRNAs and chemical additives. The trans-cleavage rate using a combination of 5 CRISPR RNAs (crRNAs) and dithiothreitol (DTT) was 89.4 times that of single crRNA. Under the optimized condition, AFCQ allows for quantifying L. plantarum genome from 1.563 × 107 copies/reaction to 1.000 × 109 copies/reaction (R2 = 0.995) with the limit of detection (LOD) at 3.142 × 106 copies/reaction. Finally, quantitative performances of AFCQ were well consistent with quantitative real-time PCR by detecting L. plantarum spiked in 7 real fermented food samples. We expected that AFCQ could be widely used to quantify various target microbes in food fermentations and standardize relevant microbial detection sectors in the food field in the near future.

The characterisation of mercury pollution in the faeces of Baltic region breeding black storks

Mercury is a pollutant that negatively impacts wildlife's physical fitness, reproduction success, as well as foraging and migrating abilities; especially high risk is posed to the animals that consume fish as their main food source, such as black storks Ciconia nigra. The black stork is a sensitive and solitary bird species, whose populations in north-eastern Europe have declined in recent years for various reasons. In this study, we present the first-ever multi-year assessment of mercury pollution in black stork faeces, analysing samples collected over a six-year period (2018–2023) from 121 nests across Latvia. We found a temporal and spatial total mercury pollution pattern and a distinction between total mercury pollution in juvenile (range: 4.75–521.78 ng/g) and adult (range: 7.32–365.60 ng/g) black stork faeces. Total mercury concentrations also differed based on faeces colour – light faeces had a statistically significant lower mercury concentration than dark faeces. In addition, we tested juvenile black stork food samples gathered from the nests and found up to five times higher total mercury concentrations than the government-permitted limit. Causes for the variability of mercury pollution across different nest sites as well as between adult and juvenile black storks are still open for future studies.

Recent Advances in Monitoring Microbial Toxins in Food Samples by HPLC-Based Techniques: A Review

This study examines the significant impact of bacterial, algal, and fungal toxins on foodborne illnesses, and stresses the importance of advanced detection techniques, such as high-performance liquid chromatography (HPLC)-based methodologies. It emphasizes the urgent need for further advancements in these techniques to ensure food safety, as they offer significant benefits, including low detection limits and the ability to be combined with other techniques to detect a wide range of toxins. In this regard, HPLC has emerged as a versatile and sensitive analytical technique for this purpose. Various HPLC methods, often enhanced with detectors such as ultraviolet (UV), fluorescence (FD), and mass spectrometry (MS), have been developed to identify and quantify microbial toxins in a wide variety of food samples. Recent advancements include HPLC-FD methods that utilize the natural fluorescence of certain aflatoxins, improving detection sensitivity. HPLC-MS/MS and UHPLC-MS/MS techniques offer high selectivity and sensitivity, making them suitable for detecting a wide range of toxins in trace quantities. The adaptability of HPLC, combined with innovative detection technologies and sample preparation methods, holds significant potential for enhancing food safety monitoring and reducing the global burden of foodborne diseases.

Rational design of carbon dot nanozymes for ratiometric dual-signal and smartphone-assisted visual detection of nitrite in food matrices

Developing reliable nitrite (NO2−) sensors is essential for food safety and reducing health risks from NO2− exposure. In this study, we strategically designed nitrogen-doped carbon dot (N-CD) nanozymes to establish an accessible dual-signal ratiometric sensing system for detecting NO2− in food matrices. This system utilizes the photoluminescence and enzyme-like properties of N-CD nanozymes combined with NO2−-triggered diazotization reactions of substrates such as o-phenylenediamine (OPD) or 3,3′,5,5′-tetramethylbenzidine (TMB). The resulting N-CD/OPD and N-CD/TMB composites provide dual-mode detection—fluorescence and colorimetric—with high selectivity for NO2− and excellent resistance to interference. These sensors exhibit clear color changes under both ultraviolet and visible light, and can be combined with smartphones for visual, on-site detection of NO2−. By incorporating a ratiometric strategy, dual-signal output, and smartphone compatibility, our system achieved a low detection limit (≤ 1.92 μM) and satisfactory recovery rates (85.6–115 %) in environmental water and food samples. This highlights the potential of smartphone-assisted sensors for environmental monitoring and food safety applications. Our carbon dot-based platform offers a practical and effective solution for on-site NO2− detection, contributing valuable insights to the field.

Smartphone-based electrochemical sensing of propyl gallate in food samples by employing NiFe-Oxide decorated flexible laser-induced graphene electrode

Flexible graphene electronics utilizing laser-induced graphene (LIG) technology offer an efficient, cost-effective, and mask-free approach to produce graphene in a single step. LIG can be directly patterned on polyimide films, impacting their surface properties, chemical composition, and electrical conductivity. However, the electrochemical performance of standalone LIG is limited. To address this, the study enhances LIG by synthesizing nickel-iron Prussian blue analogues through co-precipitation and calcination, forming porous NiFe-Oxide, which is subsequently deposited onto the LIG surface via a facile physical deposition method. The porous NiFe-Oxide@LIG electrode material demonstrates excellent electrochemical sensing capabilities due to its high conductivity, improved surface area, enhanced active sites, and superior electrocatalytic performance for detecting the antioxidant propyl gallate (PG). This porous NiFe-Oxide@LIG electrode material features a linear detection range (0.5–5 μM), low detection limit (0.01 μM), high sensitivity (17.12 μAμM−1cm−2), and strong selectivity for PG. Additionally, it offers high reproducibility and repeatability, evidenced by the low relative standard deviation values of 2.61 % and 1.96 %, respectively. The practicality of the proposed sensor was validated using food samples, integrated into a smartphone-based sensing device, achieving satisfactory recovery rates above 79.2 %. This smartphone-based sensor enables effective onsite food quality and safety monitoring.

A colorimetric fluorescent probe for reversible detection of HSO3−/H2O2 and effective discrimination of HSO3−/ClO− and its application in food and bioimaging

In view of the significant role of reactive sulfur species (RSS) and reactive oxygen species (ROS) in maintaining the redox homeostasis of organisms, we proposed a colorimetric fluorescent probe (HTN) for reversible detection of HSO3−/H2O2 and effective discrimination of HSO3−/ClO−. C = C is the active site for the Michael addition of HSO3− and the oxidation of ClO−. When HTN interacts with HSO3− and ClO−, it exhibits fluorescence quenching. The addition of oxidizing H2O2 to the system can restore the conjugate structure of the addition product of HSO3− (HTN-HSO3−) and the fluorescence recovery, but it cannot restore the structure of the oxidation product of ClO− (HTN-ClO−). By studying the change of the reversibility/non-reversibility of the probe structure with the addition of H2O2, the purpose of reversible detection of HSO3−/H2O2 and distinguishing HSO3−/ClO− is achieved. In addition, HTN can not only be used as a fluorescent ink to detect HSO3− on the test paper, but also has excellent detection effect on HSO3− and ClO− in real food samples and water samples. Meantime, HTN has good biocompatibility and can target mitochondria to achieve reversible detection of HSO3−/H2O2 and effective discrimination of HSO3−/ClO− in living cells. Therefore, HTN has great potential as a molecular tool for studying redox homeostasis in the interaction network of complex living systems.

Advanced electrochemical detection of carbendazim in staple food samples using cobalt hydroxide/titanium dioxide nanocomposite

This research introduces a novel composite material, cobalt hydroxide/titanium dioxide (Co(OH)2/TiO2), engineered for the detection of the fungicide carbendazim (CBZ) in environmental samples. A glassy carbon electrode (GCE) was modified with Co(OH)2/TiO2 to create an electrochemical sensor capable of highly sensitive CBZ detection. Differential pulse voltammetry was utilized to quantify various CBZ concentrations, revealing that the Co(OH)2/TiO2-GCE sensor provided robust response signals across a concentration range from 0.039 μM to 2630.1 μM, with a detection limit of 0.007 μM. The sensor demonstrated notable stability, reproducibility, and selectivity towards CBZ, attributable to the synergistic effects of Co(OH)2/TiO2. Additionally, the Co(OH)2/TiO2-GCE sensor proved effective for analyzing CBZ in fruit and vegetable samples. Thus, this sensor presents significant potential for widespread application in environmental monitoring and food safety assessments.

Novel Colorimetric and Near-Infrared Ratiometric Fluorescent Probe for Sensing Cysteine in Food Samples, Plants, and Living Cells.

Cysteine (Cys) is a crucial biothiol that acts a significant function in food samples and biological systems, including plant roots and living cells. Hence, we developed a novel colorimetric and near-infrared ratiometric fluorescent probe (CT), composed of coumarin and tetrahydroacridine-conjugated indole salt, for the detection of Cys. Upon reaction with Cys, the probe undergoes a specific N-substitution reaction, resulting in a notable colorimetric change and a significant ratiometric fluorescent response in both visible and near-infrared emission channels. These dual-channel ratiometric fluorescence changes are completely independent, enabling the probe to obtain great selectivity, sensitivity, and exceptional detection accuracy. Leveraging these attributes, the probe was employed to provide accurate quantitative analysis of Cys in food samples. Furthermore, confocal imaging demonstrated that the probe could monitor both exogenous and endogenous Cys levels in living cells and track Cys changes in plant roots under heavy metal stress. This work presents a dependable and accurate imaging solution for tracking and identifying Cys of real food, plants, and living cells.

Trimetallic ZIFs-derived nanoarchitecture for portable wireless electrochemical determination of chlorogenic acid in natural medicine and food samples

In this paper, a novel trimetallic zeolitic imidazolate frameworks (ZnCoMn-ZIFs) was successfully synthesized by a facile one-pot method at room temperature, which was further used to prepare a triatomic site anchored in N-doped carbon (Co2MnN8@C) hybrid nanostructure via a pyrolysis method. The synthesized Co2MnN8@C was modified on the screen-printed carbon electrode, and the modified electrode was used for the portable wireless sensitive determination of chlorogenic acid (CGA) by differential pulse voltammetry. The Co2MnN8@C exhibited large surface area and excellent catalytic activity with increasing Co and Mn sites, which could selectively combine with CGA to enhance the sensitivity of the electrochemical sensor. Under the optimized conditions, the constructed sensor had wider linear ranges for CGA analysis from 0.05–10.0 μmol/L and 10.0–100.0 μmol/L with a detection limit of 0.0075 μmol/L (3S0/S). The sensor was successfully applied to detect CGA in natural medicine and food samples with satisfied recoveries. Therefore, the proposed strategy may stimulate the exploration of trimetallic ZIFs with more active sites for the development of sensitive electrochemical sensors.

Environmental monitoring of Listeria monocytogenes contamination in dairy processing facilities combining culturing technique and molecular methods

Objectiveof the present study was to investigate Listeria contamination in Sardinian sheep cheese-making plants using culture and DNA-based methods. Food and environmental samples were collected from different surfaces of 14 facilities. Samples were collected using pre-moistened sponge swabs. Each site was sampled using two sponges used one for microbiological detection and the other for extraction of total DNA. The DNA was submitted to real time PCR targeting the prs gene for Listeria spp., the gene inlA for Listeria monocytogenes and the gene iap for Listeria innocua. DNA metabarcoding was also conducted on the total DNA. Overall were collected 254 environmental and 36 food samples. The prevalence of Listeria spp. and Listeria monocytogenes was 18.6% and 10.0%, respectively. Samples enrichment coupled with quantitative PCR (qPCR) showed a greater sensitivity than the conventional culture method with an overall prevalence of 12.1% for L. monocytogenes. Both, qPCR and ribosomal DNA-metabarcoding conducted on total DNA extracted from the sponges performed poorly in comparison to the culture-based method detecting the presence of Listeria genus in as little as 7 (2.4%) and 4 (1.4%) samples respectively. The present study supports the use of a culture enrichment coupled with qPCR for routine monitoring of contamination in food premises.

Assessment of Fungal and Contamination of Ochratoxin A and Patulin in Foods Susceptible to Contamination in the Yangzhou Market, China

The conducive conditions of warm and humid climates can facilitate mold proliferation and subsequent mycotoxin production during food processing and distribution, thereby posing a potential risk to consumer health. However, there exists a significant lack of research regarding the diversity of molds and the presence of ochratoxin A (OTA) and patulin (PAT) in food products available in the Yangzhou market. This study was conducted to assess OTA contamination levels and fungal presence in 57 cereal-based food samples, as well as PAT contamination levels and fungal presence in 50 types of foods, including apples, hawthorn berries, pears, and their derivatives. Ochratoxin A (OTA) was detected in 17 out of 57 cereal-based food samples, with concentrations ranging from 0.93 to 32.69 μg/kg. The contamination rate was determined to be 31.48%, and no samples exceeded the established regulatory limits. Furthermore, seven apple products were identified as contaminated with patulin (PAT), exhibiting concentrations between 26.85 and 192.78 μg/kg. Additionally, three food samples derived from hawthorn showed PAT contamination levels ranging from 29.83 to 88.56 μg/kg. Through purification on potato dextrose agar (PDA) medium, observation of colony morphology, and analysis of internal transcribed spacer (ITS) sequences, a total of 35 fungal strains belonging to 13 genera were identified in cereal-based foods. The predominant genera in cereals included Talaromyces, Fusarium, Aspergillus, and Penicillium. Additionally, twelve fungal strains from five genera (Penicillium, Cladosporium, Aureobasidium, Curvularia, and Alternaria) were isolated and identified in fruits and their derivatives. The findings indicate that OTA and PAT toxins are one of the important risk factors that threaten consumer health. Furthermore, the contamination of some other toxigenic strains is also a matter of substantial concern, with potential implications for consumer health.

A novel mechanistic model for predicting shrinkage kinetics in plant-based foods by integrating solid matrix mobility and viscoelasticity

Deformation during drying is a major physical change influencing drying kinetics and final product quality. Therefore, accurate prediction of shrinkage kinetics is essential for determining the optimal drying conditions for these foods. Shrinkage kinetics is greatly influenced by their structural mobility (rubbery-glassy transition) and viscoelastic properties. The current deformation models lack a comprehensive integration of structural mobility and viscoelasticity concepts, resulting in limitation in attaining insights on physiochemical state variations and viscoelastic stresses developed during drying. In order to overcome this limitation, this study proposes a novel mechanistic shrinkage model that combines solid matrix mobility-based shrinkage velocity and viscoelasticity consideration, incorporating variable mechanical properties to simulate deformation arising from moisture loss and pressure gradient respectively. Comparison between predicted drying kinetics and shrinkage evolution with experimental observation yielded close agreement, achieving low mean absolute error values. As the drying process progressed, a distinct anisotropic shrinkage pattern emerged, which is attributed to varied structural mobility based on temperature and moisture distribution across the food sample. Notably, shrinkage driven by moisture loss significantly outweighed that induced by pressure, exerting a predominant influence on overall volume change. Furthermore, the model demonstrated heightened sensitivity to water transport parameters compared to mechanical factors, which indicates the significance of moisture dynamics in shaping the drying process. Combined consideration of physiochemical changes and viscoelastic concept in the developed deformation model extends new possibility towards optimizing the drying process as well as quality aspect evaluation.