Risk management of ochratoxigenic fungi and ochratoxin A in maize grains by bioactive EVOH films containing individual components of some essential oils

Assessment of fungal species in some spices using molecular study with detection of their mycotoxins using chromatography analysis

Spices are food flavouring agents that are highly used in Iraq. However, they may be contaminated by toxicogenic fungi and subsequent production of mycotoxins. The aim of this study was to investigate the contamination of commonly used spices with fungi using polymerase chain reaction (PCR) assay and to detect fungal mycotoxin using high-performance liquid chromatography. Thirty-five spices (seven samples from each black pepper, red pepper, turmeric, cumin and ginger) were cultured on an appropriate medium to identify various fungi species. Later on, the toxigenicity of Aspergillus flavus and Aspergillus niger was determined using a PCR assay. The fungal mycotoxins, including aflatoxins and ochratoxins, were then determined through a high-performance liquid chromatography using the validated Quick, Easy, Cheap, Effective, Rugged, and Safe (QuECHERS) method. Aspergillus species were the predominantly isolated fungi, followed by Penicillium and Fusarium. The PCR results indicate the high toxigenicity of A. flavus as 85.7% of the strains had aflQ/aflR genes and 79% had PKS15KS/PKS15C-MeT genes. Regarding mycotoxin contamination in spices, the highest rates of aflatoxins and ochratoxins were found in black pepper (5.913 μg/kg) and red chilli (6.9055 μg/kg), respectively. Spices are susceptible substrates for the growth of mycotoxigenic fungi. Thus, regular effective surveillance and quality control procedures are highly recommended.

Fortification of polysaccharide-based packaging films and coatings with essential oils: A review of their preparation and use in meat preservation

As the demand for botanical food additives and eco-friendly food packaging materials grows, the use of essential oils, edible biodegradable films and coatings are becoming more popular in packaging. In this review, we discussed the recent research trends in the use of natural essential oils, as well as polysaccharide-based coatings and films: from the composition of the substrates to preparing formulations for the production of film-forming technologies. Our review emphasized the functional properties of polysaccharide-based edible films that contain plant essential oils. The interactions between essential oils and other ingredients in edible films and coatings including polysaccharides, lipids, and proteins were discussed along with effects on film physical properties, essential oil release, their active role in meat preservation. We presented the opportunities and challenges related to edible films and coatings including essential oils to increase their industrial value and inform the development of edible biodegradable packaging, bio-based functional materials, and innovative food preservation technologies.

Impact of environmental factors on ochratoxin A: From natural occurrence to control strategy

Ochratoxin A (OTA) contamination and the associated issues of food security, food safety and economic loss are widespread throughout the world. The occurrence of OTA depends on ochratoxigenic fungi, foodstuffs and their environment. In this review, natural occurrence and control strategy of OTA, with a focus on the impact of environmental factors, are summarized. First, this manuscript introduces potentially contaminated foodstuffs, including the emerging ones which are not regulated in international legislation. Secondly, it gives an update of native producers based on foodstuffs and OTA biosynthesis. Thirdly, complicated environmental regulation is disassembled into individual factors in order to clarify their regulatory effect and mechanism. Finally, to emphasize control OTA at all stages of foodstuffs from farm to table, strategies used at crop planting, harvest, storage and processing stages are discussed.

Cereal and Confectionary Packaging: Background, Application and Shelf-Life Extension

In both public and private sectors, one can notice a strong interest in the topic of sustainable food and packaging. For a long time, the spotlight for optimization was placed on well-known examples of high environmental impacts, whether regarding indirect resource use (e.g., meat, dairy) or problems in waste management. Staple and hedonistic foods such as cereals and confectionary have gained less attention. However, these products and their packaging solutions are likewise of worldwide ecologic and economic relevance, accounting for high resource input, production amounts, as well as food losses and waste. This review provides a profound elaboration of the status quo in cereal and confectionary packaging, essential for practitioners to improve sustainability in the sector. Here, we present packaging functions and properties along with related product characteristics and decay mechanisms in the subcategories of cereals and cereal products, confectionary and bakery wares alongside ready-to-eat savories and snacks. Moreover, we offer an overview to formerly and recently used packaging concepts as well as established and modern shelf-life extending technologies, expanding upon our knowledge to thoroughly understand the packaging’s purpose; we conclude that a comparison of the environmental burden share between product and packaging is necessary to properly derive the need for action(s), such as packaging redesign.

The control of fungi and mycotoxins by food active packaging: a review

Conventionally used petrochemical-based plastics are poorly degradable and cause severe environmental pollution. Alternatively, biopolymers (e.g., polysaccharides, proteins, lipids, and their blends) are biodegradable and environment-friendly, and thus their use in packaging technologies has been on the rise. Spoilage of food by mycotoxigenic fungi poses a severe threat to human and animal health. Hence, because of the adverse effects of synthetic preservatives, active packaging as an effective technique for controlling and decontaminating fungi and related mycotoxins has attracted considerable interest. The current review aims to provide an overview of the prevention of fungi and mycotoxins through active packaging. The impact of different additives on the antifungal and anti-mycotoxigenic functionality of packaging incorporating active films/coatings is also investigated. In addition, active packaging applications to control and decontaminate common fungi and mycotoxins in bakery products, cereal grains, fruits, nuts, and dairy products are also introduced. The results of recent studies have confirmed that biopolymer films and coatings incorporating antimicrobial agents provide great potential for controlling common fungi and mycotoxins and enhancing food quality and safety.

Combinational inhibitory action of essential oils and gamma irradiation for controlling Aspergillus flavus and Aspergillus parasiticus growth and their aflatoxins biosynthesis in vitro and in situ conditions

The purpose of this study was to investigate the effects of certain essential oils (star anise, lemon leaves, marjoram, fennel, and lavender) on the fungal growth of Aspergillus flavus and Aspergillus parasiticus and their production of aflatoxin B1 (AFB1). The degree of suppression of the aflatoxigenic strains' growth and their production of AFB1 is mainly affected by the kind and the concentration of the tested essential oils (EOs). Star anise essential oil had the lowest minimum inhibitory concentration (0.5 and 1.0 μL/mL) against A. flavus and A. parasiticus, respectively, so it was the best among the five different oils. The study of liquid chromatography with tandem mass spectrometry revealed that star anise EO resulted in a 98% reduction in AFB1 without a breakdown of AFB1 products after treatment thus the complete removal of AFB1 was done without any toxic residues. The combination showed a synergistic effect, the combinational treatment between γ-irradiation at a low dose (2 kGy) and star anise EO at concentrate 0.5 μL/g destroyed A. flavus and A. parasiticus inoculated (individually) in sorghum and peanut, respectively throughout the storage period (8 weeks).

Self-stick membrane based on grafted gum Arabic as active food packaging for cheese using cinnamon extract

Encapsulation of volatile essential oils has been investigated to provide an active food packaging (AFP) material with more control over their fast release and pungent smell. In this work, Gum Arabic-based adhesive membrane was developed as a self-stick AFP material, delivering cinnamon essential oil (CEO) in vapor phase. Gum Arabic (GA) was grafted with butyl acrylate (BA) and hydroxyethyl methacrylate [GA-g-poly(BA-HEMA)]. Adhesive membrane was characterized by means of spectral, physicochemical and rheological analysis. GA-adhesive membrane made of 5% wt/v GA, 3.5 m mol HEMA, and 87 m mol BA with 21 N/m tack are loaded with 4, 8 and 10% v/v of CEO and used for antimicrobial bioassays. GA-g-poly(BA-HEMA) membrane prolonged CEO release up to 2 days. 8%v/v CEO showed superior activities against both Gram negative and positive bacteria. Shelf-life of cheese samples, packed with the self-stick membranes loaded with cinnamon extract, has extended from 3 to 8 weeks. Cheese samples that inoculated with shiga toxin producing E. coli O157:H7 and packed in plastic boxes with the self-stick AFP (4, 8 and 10 % CEO), showed significant reduction in the total bacteria counts.

Comparative Analysis of Machine Learning Methods to Predict Growth of F. sporotrichioides and Production of T-2 and HT-2 Toxins in Treatments with Ethylene-Vinyl Alcohol Films Containing Pure Components of Essential Oils

The efficacy of ethylene-vinyl alcohol copolymer films (EVOH) incorporating the essential oil components cinnamaldehyde (CINHO), citral (CIT), isoeugenol (IEG), or linalool (LIN) to control growth rate (GR) and production of T-2 and HT-2 toxins by Fusarium sporotrichioides cultured on oat grains under different temperature (28, 20, and 15 °C) and water activity (a_w) (0.99 and 0.96) regimes was assayed. GR in controls/treatments usually increased with increasing temperature, regardless of a_w, but no significant differences concerning a_w were found. Toxin production decreased with increasing temperature. The effectiveness of films to control fungal GR and toxin production was as follows: EVOH-CIT > EVOH-CINHO > EVOH-IEG > EVOH-LIN. With few exceptions, effective doses of EVOH-CIT, EVOH-CINHO, and EVOH-IEG films to reduce/inhibit GR by 50%, 90%, and 100% (ED₅₀, ED₉₀, and ED₁₀₀) ranged from 515 to 3330 µg/culture in Petri dish (25 g oat grains) depending on film type, a_w, and temperature. ED₉₀ and ED₁₀₀ of EVOH-LIN were >3330 µg/fungal culture. The potential of several machine learning (ML) methods to predict F. sporotrichioides GR and T-2 and HT-2 toxin production under the assayed conditions was comparatively analyzed. XGBoost and random forest attained the best performance, support vector machine and neural network ranked third or fourth depending on the output, while multiple linear regression proved to be the worst.

Edible Films and Coatings as Food-Quality Preservers: An Overview

Food preservation technologies are currently facing important challenges at extending the shelf-life of perishable food products (e.g., meat, fish, milk, eggs, and many raw fruits and vegetables) that help to meet the daily nutrient requirement demand. In addition, food preservation has gone beyond only preservation; the current techniques are focused on the fulfillment of two additional objectives, the suitability of the used processes and generation of environmentally friendly products with non-presence of any side effect on health. Moreover, they are also looking for additional nutritional properties. One of these preservation protocols deals with the use of edible films and coatings. Therefore, this review shows an overview of synthetic materials (e.g., glass, aluminum, plastic, and paperboard), as well as the regulations that limit their application in food packaging. Further, this review releases the current-state-of-the-art of the use of films and edible coatings as an alternative to conventional packaging, providing the main features that these biodegradable packaging should meet towards specific uses for the conservation and improvement of various food products. Herein, particular attention has been paid to the main used components (e.g., biopolymers, additives, bioactive, and probiotic components), manufacturing methods (for edible films or coatings) and their application to specific products. In addition, an outlook of the application of edible films and coatings as quality indicators of perishable products is shown.

Machine learning approach for predicting Fusarium culmorum and F. proliferatum growth and mycotoxin production in treatments with ethylene-vinyl alcohol copolymer films containing pure components of essential oils

Fusarium culmorum and F. proliferatum can grow and produce, respectively, zearalenone (ZEA) and fumonisins (FUM) in different points of the food chain. Application of antifungal chemicals to control these fungi and mycotoxins increases the risk of toxic residues in foods and feeds, and induces fungal resistances. In this study, a new and multidisciplinary approach based on the use of bioactive ethylene-vinyl alcohol copolymer (EVOH) films containing pure components of essential oils (EOCs) and machine learning (ML) methods is evaluated. Bioactive EVOH-EOC films were made incorporating cinnamaldehyde (CINHO), citral (CIT), isoeugenol (IEG) or linalool (LIN). Several ML methods (neural networks, random forests and extreme gradient boosted trees) and multiple linear regression (MLR) were applied and compared for modeling fungal growth and toxin production under different water activity (a_w) (0.96 and 0.99) and temperature (20 and 28 °C) regimes. The effective doses to reduce fungal growth rate (GR) by 50, 90 and 100% (ED₅₀, ED₉₀, and ED₁₀₀) of EOCs in EVOH films were in the ranges 200 to >3330, 450 to >3330, and 660 to >3330 μg/fungal culture (25 g of partly milled maize kernels in Petri dish), respectively, depending on the EOC, a_w and temperature. The type of EVOH-EOC film and EOC doses significantly affected GR in both species and ZEA and FUM production. Temperature also affected GR and a_w only affected GR and FUM production of F. proliferatum. EVOH-CIT was the most effective film against both species and ZEA and FUM production. Usually, when the EOC levels increased, GR and mycotoxin levels in the medium decreased although some treatments in combination with certain a_w and temperature values induced ZEA production. Random forest models predicted the GR of F. culmorum and F. proliferatum and ZEA and FUM production better than neural networks or extreme gradient boosted trees. The MLR mode provided the worst performance. This is the first approach on the ML potential in the study of the impact that bioactive EVOH films containing EOCs and environmental conditions have on F. culmorum and F. proliferatum growth and on ZEA and FUM production. The results suggest that these innovative packaging systems in combination with ML methods can be promising tools in the prediction and control of the risks associated with these toxigenic fungi and mycotoxins in food.

A label-free, direct solid-phase fluorimetric analysis of ochratoxin A in agricultural products with monoclonal antibody-immobilized monolith

We established a method for directly measuring mycotoxin ochratoxin A (OTA) in foods by solid-phase fluorescence of monolith-immobilized antibodies. The antibody was introduced onto only one side of an 8 mm-diameter, 3 mm-thick monolith via covalently immobilized protein G. 4 μg (2.7 × 10^-11 mol) of antibody was immobilized per one monolith. A maximum of 10 μg (2.4 × 10^-11 mol) OTA adsorbed to the activated side of each monolith. The amount of OTA adsorbed and the fluorescence intensity showed good linearity in the range of 0.5-3 ng OTA. Loading the sample solution onto the non-antibody side on the monolith blocked the hydrophobic fluorescent matrices from reaching the immobilized surface of the antibody. The proposed method was able to detect 1 ng OTA/g in solid samples with complex matrices. Mean recoveries obtained at spiked concentration of 3 ng g^-1 OTA/g were 78-90% with relative standard deviations of <7.9%.

Preparation of Antimicrobial Fibres from the EVOH/EPC Blend Containing Silver Nanoparticles

The article presents a new fabrication method for bioactive fibres with a microporous structure of ethylene–vinyl alcohol copolymers (EVOH)/ethylene−propylene copolymer (EPC) blends. The experimental work carried out resulted in obtaining EVOH/EPC polymer blends fibres with the addition of glycerol and sodium stearate. Different concentrations of glycerol (38%, 32%) and sodium stearate (2%, 8%) were used to prepare the fibres. The purpose of using different concentrations of stearate and glycerol was to evaluate the effect of additives on the structure and properties of the fibres. A significant influence of the additives used on the morphological structure of the fibres was found. The resulting fibres were modified with an AgNO₃ solution and reduced to silver nanoparticles (AgNPs), to give the fibres bioactive properties. The fibres obtained with the addition of 8% stearate have a more developed surface, which may influence the amount of adsorbed silver particles inside the fibre. However, the durability of depositing silver particles after multiple washes has not been tested. Three types of microorganisms were selected to assess the microbiological activity of the obtained fibres, i.e., Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli. The fibres have antibacterial activity against gram positive and negative bacteria. The largest inhibition zones were obtained for gram-positive bacteria Staphylococcus aureus, ranging from 3 to 10 mm depending on the concentration of AgNPs. The morphology of the blends fibres was characterized by scanning electron microscopy (SEM) and optical microscopy (OM). The occurrence of elemental silver was analysed by energy dispersive spectroscopy (EDS) analysis. The changes of the polymer structure chemistry are studied by Fourier transform infrared spectroscopy (FTIR).

Preparation and application of a high-temperature–resistant EVOH-SO3Li/PI fiber membrane with self-closing pores

A lithium ethylene-vinyl alcohol copolymer sulfate (EVOH-SO3Li)/polyimide (PI) composite fiber membrane prepared via high-voltage electrospinning and impregnation was used as a lithium-ion battery separator for research purposes. The polyamic acid spinning solution was synthesized from 3,3′′,4,4′′-benzophenone tetracarboxylic dianhydride and 4,4-diaminodiphenyl ether. The PI fiber membrane was prepared via high-voltage electrospinning and thermal imidization, and EVOH-SO3Li was then coated on the surface of the PI fiber to prepare an EVOH-SO3Li/PI composite fiber membrane material (t-EVOH-SO3Li/PI). Overall, the EVOH-SO3Li/PI membrane exhibits excellent basic physical properties, given the clear three-dimensional network microstructure. When compared with EVOH-SO3Li/PI composite fiber membrane prepared via the cospinning method (s-EVOH-SO3Li/PI), its electrolyte uptake and tensile strength can increase to 739% and 17.56 MPa, respectively. Additionally, the EVOH-SO3Li/PI composite fiber membrane prepared via high-voltage electrospinning and impregnation exhibits better heat shrinkage stability, electrochemical performance, and high-temperature self-closing pores function. The electrochemical stability window, electrochemical impedance, and ionic conductivity correspond to 5.8 V, 310 Ω, and 3.753 × 10−3 S cm−1, respectively. Specifically, at 200°C, the internal pores can close effectively, and this is extremely important for the safety of lithium-ion batteries.

Inhibitory effect of C. zeylanicum, C. longa, O. basilicum, Z. officinale, and C. martini essential oils on growth and ochratoxin A content of A. ochraceous and P. verrucosum in maize grains

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Essenetial oils (EOs) extrcated by hydrodistillation and chemical profile deduced by GC–MS.

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EOs shown potential antioxidant activity by DPPH and ABTS assay.

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EOs presented superlative antifungal activity against P. verrucosum related to A. ochraceus.

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C. zeylanicum and C. martini EOs presented superlative antifungal activity related to other EOs.

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C. zeylanicum EO inhibited the growth and OTA of fungi at 1500 μg/g in maize grains.

In the study, antifungal and ochratoxin A (OTA) production inhibitory activities of essential oils (EOs) of Cinnamomum zeylanicum, Curcuma longa, Ocimum basilicum, Zingiber officinale, and Cymbopogon martini were reported on Aspergillus ochraceus and Penicillium verrucosum. EOs were obtained by hydrodistillation and GC–MS technique was chosen to deduce their chemical profile. Major chemical compounds in EOs of C. zeylanicum, C. longa, O. basilicum, Z. officinale, and C. martini were (E)-cinnamaldehyde (35.81 %), ar-turmerone (46.13 %), eugenol (36.58 %), geranyl proprionate (18.93 %), and geranyl acetate (14.88 %), respectively. The EOs shown potent antioxidant activity by DPPH and ABTS assays. The EOs presented superlative antifungal activity against P. verrucosum related to A. ochraceus. The C. zeylanicum and C. martini EOs shown superlative antifungal activity related to other EOs. The C. zeylanicum and C. martini EOs completely inhibited the growth and OTA production of P. verrucosum and A. ochraceous at 1500 and 2500 μg/g in maize grains, respectively.

A structural determinant of mycophenolic acid resistance in eukaryotic inosine 5'-monophosphate dehydrogenases

Mycophenolic acid (MPA) is a potent natural product inhibitor of fungal and other eukaryotic inosine 5'-monophosphate dehydrogenases (IMPDHs) originally isolated from spoiled corn silage. MPA is produced by the filamentous fungi Penicillium brevicompactum, which contains two IMPDHs, PbIMPDHA and PbIMPDHB, both of which are MPA-resistant. The MPA binding sites of these enzymes are identical to MPA-sensitive IMPDHs, so the structural determinants of resistance are unknown. Here we show that a single residue, Ser267, accounts for the MPA resistance of PbIMPDHA. Substitution of Ser267 with Ala, the residue most commonly found in this position in eukaryotic IMPDHs, makes PbIMPDHA sensitive to MPA. Conversely, Aspergillus nidulans IMPDH becomes MPA-resistant when the analogous Ala residue is substituted with Ser. These substitutions have little effect on the catalytic cycles of either enzyme, suggesting the fitness costs are negligible despite the strong conservation of Ala at this position. Intriguingly, while only 1% of fungal IMPDHs contain Ser or Thr at position 267, these residues are found in the IMPDHs from several Aspergillus species that grow at the low temperatures also favored by Penicillium. Perhaps Ser/Thr267 is an evolutionary signature of MPA exposure.

Antifungal effect of engineered silver nanoparticles on phytopathogenic and toxigenic Fusarium spp. and their impact on mycotoxin accumulation

Cereal grains are essential ingredient in food, feed and industrial processing. One of the major causes of cereal spoilage and mycotoxin contamination is the presence of toxigenic Fusarium spp. Nanoparticles have immense applications in agriculture, nutrition, medicine or health but their possible impact on the management of toxigenic fungi and mycotoxins have been very little explored. In this report, the potential of silver nanoparticles (AgNPs) (size 14-100 nm) against the major toxigenic Fusarium spp. affecting crops and their effect on mycotoxin accumulation is evaluated for the first time. The studied Fusarium spp. (and associated mycotoxins) were F. graminearum and F. culmorum (deoxynivalenol, 3-acetyldeoxynivalenol and zearalenone), F. sporotrichioides and F. langsethiae (T-2 and HT-2 toxins), F. poae (nivalenol), F. verticillioides and F. proliferatum (fumonisins B₁ and B₂) and F. oxysporum (mycotoxins no detected). The factors fungal species, AgNP dose (range 2-45 μg/mL), exposure time (range 2-30 h) and their interactions significantly influence spore viability, lag period and growth rate (GR) in subsequent cultures in maize-based medium (MBM) of all the studied species. The effective lethal doses (ED₅₀, ED₉₀ and ED₁₀₀) to control spore viability and GR were in the range 1->45 μg/mL depending on the remaining factors. At high exposure times (20-30 h), the three effective doses ranged 1-30 μg/mL for all the studied species. At the end of the incubation period (10 days) mycotoxin levels in MBM cultures inoculated with fungal spores from treatments were strongly related with the size reached by the colony at that time. None of the treatments produced stimulation in conidia germination, GR or mycotoxin biosynthesis with respect to controls. Thus, the antifungal effect of the assayed AgNPs against the tested Fusarium spp. suggests that AgNPs could be a new antifungal ingredient in bioactive polymers (paints, films or coating) likely to be implemented in the agro-food sector for controlling these important toxigenic Fusarium spp. and their main associated mycotoxins.

An iridium(III) complex/G-quadruplex ensemble for detection of ochratoxin A based on long-lifetime luminescent

A G-quadruplex-based platform has been developed for the time-resolved monitoring of ochratoxin A (OTA). The simple platform displays good sensitivity for OTA with a detection limit of 40 nM via steady-state emission spectroscopy. Notably, the platform showed a detection limit of 10.8 nM via time-resolved emission spectroscopy (TRES), which is about 4 times more sensitive than steady-state mode. Moreover, the probe showed excellent selectivity for OTA over other mycotoxins. Furthermore, OTA was successfully detected in actual herbal plant extracts samples. Our platform is the first to detect OTA using TRES to distinguish between the target signals versus the auto-fluorescence of real samples. This platform shows improved detection speed, accuracy and sensitivity with simple operation, low cost, and no requirement for complicated pre-processing.

Evaluation of the antifungal activity of individual and combined monoterpenes against Rhizopus stolonifer and Absidia coerulea

The development of natural plant extracts and essential oils will help to decrease the negative effects of synthetic chemicals. In the present study, the antifungal activity of individual and combined monoterpenes against Rhizopus stolonifer and Absidia coerulea was evaluated. The results from antifungal tests showed that eugenol, carvacrol, and isoeugenol, among all the tested compounds, exhibited strong antifungal activity against the two tested fungi. Furthermore, carvacrol exhibited the most toxic effects against R. stolonifer and A. coerulea, and the IC₅₀ values of carvacrol for the two fungi were 44.94 μg/ml and 50.83 μg/ml, respectively. The compounds (±)-menthol, b-citronellol, geraniol, 3,7-dimethyl-1-octanol, citral, and cuminaldehyde had only strong antifungal activity against R. stolonifer. In addition, the value of the synergistic co-efficient (SR) of a combination of isoeugenol and eugenol (1:1) showed an additive effect against R. stolonifer. The combination of isoeugenol and cuminaldehyde (1:1) showed an antagonistic effect against A. coerulea. Our results indicated that carvacrol and isoeugenol had potential antifungal effects against the two tested fungi and could be utilized in novel biological fungicide development.