Ozonolysis mechanism and influencing factors of aflatoxin B1: A review

Aflatoxins in cereal based products-an overview of occurrence, detection and health implication

Aflatoxins are naturally produced toxins by specific molds, namely Aspergillus flavus and Aspergillus parasiticus. These toxins can be found in various agricultural products, including crops like maize, peanuts, cottonseed, and tree nuts. They have the potential to contaminate the food supply during different stages of production, processing, and storage. Aflatoxin is a very poisonous substance that has been linked to adverse health effects in both humans and animals. It is essential to detect and monitor aflatoxins to ensure the safety of food. Efficient and precise analytical techniques, such as chromatography and immunoassays, have been used to accurately measure the levels of aflatoxins in different substances. Regulatory bodies and worldwide associations have determined maximum permissible limits for aflatoxins in food and nourishment products to protect the well-being of the general public. Effectively addressing aflatoxin contamination necessitates a comprehensive approach that encompasses various strategies in agriculture, post-harvest practices, and regulatory measures. Continuous research and collaborative endeavors are crucial in order to minimize aflatoxin exposure and mitigate the associated risks. This review offers a comprehensive examination of the presence, health consequences, and elimination techniques associated with aflatoxins.

Recent advances in ratiometric electrochemical sensors for food analysis

Ratiometric electrochemical sensors are renowned for their dual-signal processing capabilities, enabling automatic correction of background noise and interferences through built-in calibration, thus providing more accurate and reproducible measurements. This characteristic makes them highly promising for food analysis. This review comprehensively summarizes and discusses the latest advancements in ratiometric electrochemical sensors and their applications in food analysis, emphasizing their design strategies, detection capabilities, and practical uses. Initially, we explore the construction and design strategies of these sensors. We then review the detection of various food-related analytes, including nutrients, additives, metal ions, pharmaceutical and pesticide residues, biotoxins, and pathogens. The review also briefly explores the challenges faced by ratiometric electrochemical sensors in food testing and potential future directions for development. It aims to provide researchers with a clear introduction and serve as a reference for the design and application of new, efficient ratiometric electrochemical sensors in food analysis.

Detoxication and bioconversion of aflatoxin B1 by yellow mealworms (Tenebrio molitor): A sustainable approach for valuable larval protein production from contaminated grain

Yellow mealworm (Tenebrio molitor) is a supplementary protein source for food and feed and represents a promising solution to manage grain contaminated with Aflatoxin B₁ (AFB₁). In this study, AFB₁ present in different concentrations in wheat bran was treated and removed via bioconversion by yellow mealworm of different instars, with emphasis on the bioconversion performance and metabolism of AFB₁. Upon application of wheat bran spiked with 100 μg/kg AFB₁ to 5th-6th instar yellow mealworms, the conversion rate of AFB₁ was up to 87.85 %. Low level of AFB₁ (< 2 μg/kg) was accumulated in the larval bodies, and the survival rate, development and nutrition contents of yellow mealworm were not significantly affected. It was revealed that 1 kg of wheat bran contaminated with AFB₁ increased the weight of yellow mealworms from 138 g to 469 g, containing approximately 103 g of protein. The bioconversion of AFB₁ by yellow mealworms led to generation of 13 metabolites in the frass and 3 metabolites in the larvae. AFB₁ was detoxicated and removed via phase I metabolism comprising reduction, dehydrogenation, hydration, demethylation, hydroxylation, decarbonylation and ketoreduction, followed by phase II metabolism involving conjugation of amino acid, glucoside and glutathione (GSH). The toxicity of AFB₁ metabolites was deemed lower than that of AFB₁ according to their structures. This study provides a sustainable approach and theoretical foundation on using yellow mealworms for cleaner grain contamination management and valuable larval protein production via bioconversion of food and feed contaminated by AFB₁.

Ozonation: an Evolving Disinfectant Technology for the Food Industry

The food processing industry is currently facing challenges in delivering safe, healthy, and high-quality food. Constant monitoring at each step of the supply chain of food is vital to resolve the issue of food contamination. To achieve this aim and to meet consumer prospects, the technologies promoting the concept of clean label food have been widely cherished. Ozonation is one such advanced technology that assists in maintaining food product quality and safety. Its manifold approach and zero-by-product production make it a promising food disinfectant technique. Ozone due to its oxidative property has been widely used in sanitizing, washing, odor removal, water treatment, and in equipment, fruits, vegetable, and meat processing disinfection. Ozonation in foods is done in such a way that no nutritional, sensory, and physicochemical characteristics are altered. In this review, an attempt is made to give an overview of the impact and contribution of ozone as a disinfectant in food processing while comparing it with conventional disinfectants and its overall application in the food industry.

Postharvest processing of tree nuts: Current status and future prospects-A comprehensive review

Tree nuts are important economic crops and are consumed as healthy snacks worldwide. In recent years, the increasing needs for more efficient and effective postharvest processing technologies have been driven by the growing production, higher quality standards, stricter food safety requirements, development of new harvesting methods, and demand to achieve energy saving and carbon neutralization. Among all, the technologies related to drying, disinfection, and disinfestation and downstream processes, such as blanching, kernel peeling, and roasting, are the most important processes influencing the quality and safety of the products. These processes make up the largest contribution to the energy consumptions and environmental impacts stemming from tree nut production. Although many studies have been conducted to improve the processing efficiency and sustainability, and preserve the product quality and safety, information from these studies is fragmented and a centralized review highlighting the important technology advancements of postharvest processing of tree nuts would benefit the industry. In this comprehensive review, almonds, walnuts, and pistachios are selected as the representative crops of tree nuts. Current statuses, recent advances, and ongoing challenges in the scientific research as well as in the industrial processing practices of these tree nuts are summarized. Some new perspectives and applications of tree nut processing waste and by-products (such as the hulls and shells) are also discussed. In addition, future trends and research needs are highlighted. The material presented here will help both stakeholders and scientists to better understand postharvest tree nut processing and provide technological recommendations to improve the efficiency and sustainability, product quality and safety, and competitiveness of the industry.

Distribution of Aspergillus Fungi and Recent Aflatoxin Reports, Health Risks, and Advances in Developments of Biological Mitigation Strategies in China

Aflatoxins (AFs) are secondary metabolites that represent serious threats to human and animal health. They are mainly produced by strains of the saprophytic fungus Aspergillus flavus, which are abundantly distributed across agricultural commodities. AF contamination is receiving increasing attention by researchers, food producers, and policy makers in China, and several interesting review papers have been published, that mainly focused on occurrences of AFs in agricultural commodities in China. The goal of this review is to provide a wider scale and up-to-date overview of AF occurrences in different agricultural products and of the distribution of A. flavus across different food and feed categories and in Chinese traditional herbal medicines in China, for the period 2000-2020. We also highlight the health impacts of chronic dietary AF exposure, the recent advances in biological AF mitigation strategies in China, and recent Chinese AF standards.

Novel strategies for degradation of aflatoxins in food and feed: A review

Aflatoxins are toxic secondary metabolites mainly produced by Aspergillus fungi, posing high carcinogenic potency in humans and animals. Dietary exposure to aflatoxins is a global problem in both developed and developing countries especially where there is poor regulation of their levels in food and feed. Thus, academics have been striving over the decades to develop effective strategies for degrading aflatoxins in food and feed. These strategies are technologically diverse and based on physical, chemical, or biological principles. This review summarizes the recent progress on novel aflatoxin degradation strategies including irradiation, cold plasma, ozone, electrolyzed oxidizing water, organic acids, natural plant extracts, microorganisms and enzymes. A clear understanding of the detoxification efficiency, mechanism of action, degradation products, application potential and current limitations of these methods is presented. In addition, the development and future perspective of nanozymes in aflatoxins degradation are introduced.

Application of ozone for degradation of mycotoxins in food: A review

Mycotoxins such as aflatoxins (AFs), ochratoxin A (OTA) fumonisins (FMN), deoxynivalenol (DON), zearalenone (ZEN), and patulin are stable at regular food process practices. Ozone (O₃ ) is a strong oxidizer and generally considered as a safe antimicrobial agent in food industries. Ozone disrupts fungal cells through oxidizing sulfhydryl and amino acid groups of enzymes or attacks the polyunsaturated fatty acids of the cell wall. Fusarium is the most sensitive mycotoxigenic fungi to ozonation followed by Aspergillus and Penicillium. Studies have shown complete inactivation of Fusarium and Aspergillus by O₃ gas. Spore germination and toxin production have also been reduced after ozone fumigation. Both naturally and artificially, mycotoxin-contaminated samples have shown significant mycotoxin reduction after ozonation. Although the mechanism of detoxification is not very clear for some mycotoxins, it is believed that ozone reacts with the functional groups in the mycotoxin molecules, changes their molecular structures, and forms products with lower molecular weight, less double bonds, and less toxicity. Although some minor physicochemical changes were observed in some ozone-treated foods, these changes may or may not affect the use of the ozonated product depending on the further application of it. The effectiveness of the ozonation process depends on the exposure time, ozone concentration, temperature, moisture content of the product, and relative humidity. Due to its strong oxidizing property and corrosiveness, there are strict limits for O₃ gas exposure. O₃ gas has limited penetration and decomposes quickly. However, ozone treatment can be used as a safe and green technology for food preservation and control of contaminants.

Detoxification of aflatoxin B1 in corn by chlorine dioxide gas

Chlorine dioxide (ClO₂) gas was utilized for detoxifying aflatoxin B₁ (AFB₁) in corn for the first time. Four degradation compounds were identified by LC-MS as C₁₇H₁₃O₈, C₁₇H₁₅O₁₀, C₁₆H₁₅O₁₀, and C₁₅H₁₁O₈. Structurally, the biological activity of ClO₂-treated AFB₁ was removed due to the disappearance of C8-C9 double bond in the furan ring and the modification of cyclopentanone and methoxy after ClO₂ treatment. The cell viability assay on human embryo hepatocytes confirmed little toxicity of the degradation products. The degradation efficiency of AFB₁ on corn peaked near 90.0% under the optimized conditions and reached 79.6% for low initial contamination of AFB₁ at 5-20 μg/kg. Accordingly, ClO₂ has the potential to be developed into an effective, efficient, and economic approach to detoxify AFB₁ in grains.

Functionalized nanoflower-like hydroxyl magnesium silicate for effective adsorption of aflatoxin B1

Aflatoxin B1 (AFB1), which is widely found in food and feed, poses a serious threat to the health of human and livestock. In this work, functionalized nanoflower-like hydroxyl magnesium silicate (FNHMS) was synthesized for adsorption of AFB1. First, bulk magnesium silicate (MS) was converted into nanoflower-like hydroxyl magnesium silicate (NHMS) by hydroxylation. Cetyltrimethylammonium bromide (CTMAB) modification then enhanced the hydrophobicity and the affinity to AFB1 of NHMS. The adsorption performance for AFB1 followed the order of MS < NHMS < FNHMS, and the adsorption performance increased with the increase of the dose of CTMAB. Isothermal adsorption analysis indicated that the surface of FNHMS was heterogeneous. The adsorption capacity of FNHMS-0.4 to AFB1 was estimated to be 27.34 mg g^-1 and 28.61 mg g^-1 by Freundlich and Dubinin-Radushkevich isotherm adsorption model, respectively. By analyzing the adsorption kinetics and adsorption thermodynamics, both physical adsorption and chemisorption existed in the process of AFB1 being adsorbed on FNHMS-0.4. Adsorption mechanisms analysis indicated that the adsorption followed the adsorption site priority of H > O > Mg. This work demonstrates that FNHMS could be a promising adsorbent for removal of AFB1.

Control of aflatoxin M1 in milk by novel methods: A review

Aflatoxin M₁ (AFM₁) in milk and milk products has been recognised as an issue for over 30 years. Controlling AFM₁ in milk is important to protect human health and trade. Preventing contamination by avoiding fungal contamination of cattle feed is the best method of control, however this is hard to avoid in some countries. Treating milk containing AFM₁ is an alternative control measure, however, there is no single approved method. The challenge is to select a treatment method that is effective but does not affect the organoleptic quality of milk. This study reviews the strategies for degrading AFM₁ in milk including yeast, lactic acid bacteria, enzyme, peroxide, ozone, UV light and cold plasma. This review compares the efficacy, influencing factors, (possible) mechanisms of activity, advantages, limitations and potential future trends of these methods and provides some recommendations for the treatment of milk to reduce the risk of AFM₁ contamination.

Cytotoxicity of Deoxynivalenol after Being Exposed to Gaseous Ozone

In this study, deoxynivalenol (DON) in aqueous solution was exposed to gaseous ozone for periods ranging from 0 to 20 min. The degradation efficiency and cytotoxicity of DON were investigated after being treated by ozone. The results showed that DON was rapidly degraded from 10.76 ± 0.09 mg/L to 0.22 ± 0.04 mg/L within 15 min (P < 0.05), representing a reduction of 97.95%, and no DON was detected after being exposed to 14.50 mg/L of ozone at a flow rate of 80 mL/min for 20 min. The degradation of DON depended on the ozone exposure time, and followed the first-order kinetic model (R2 = 0.9972). Human hepatic carcinoma (HepG2) and Henrietta Lacks (Hela) cells were used to evaluate the cytotoxicity of DON treated by ozone using the 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The half-maximal inhibitory concentrations (IC50) values of DON on HepG2 and Hela cells were 2.10 and 1.33 mg/L after 48 h of exposure, respectively, and showed a dose-dependent manner. The cell vitalities of HepG2 and Hela cells on DON were both evidently improved after being exposed to ozone for 15 min, and there were no significant differences between the negative control and that treated at 20 min of ozone exposure. Gaseous ozone can potentially be used as a new method to detoxify DON in agricultural products.

Using disease-burden method to evaluate the strategies for reduction of aflatoxin exposure in peanuts

Aflatoxin is a fungal secondary metabolite with high toxicity that is capable of contaminating various types of food crops. It has been identified as a Group 1 human carcinogen by the International Agency for Research on Cancer. Chronic aflatoxin exposure has caused worldwide concern as a matter of public food safety. Peanuts and peanut products are the major sources of aflatoxin exposure. Therefore, some reduction interventions have been developed to minimize contamination throughout the peanut production chain. The purpose of this study is to estimate the efficacy of interventions in reducing the health impact of hepatocellular carcinoma caused by aflatoxin contamination in peanuts. The estimated total Disability-Adjusted Life Years (DALYs) were calculated using FDA-iRISK software. Six aflatoxin reduction strategies were evaluated, including good agricultural practice (GAP), biocontrol, Purdue Improved Crop Storage packaging, basic processing, ozonolysis, and ultraviolet irradiation. The results indicated that basic processing could prevent huge public health loss of 4,079.7-21,833 total DALYs per year. In addition, GAP and biocontrol were both found to be effective strategies in the farm field. Meanwhile, the other three interventions had limited effectiveness in reducing total DALYs. In conclusion, this study could help farmers, processing plants, and government policy makers to alleviate aflatoxin contamination issues in the peanut production chain.

Aflatoxins in Food and Feed: An Overview on Prevalence, Detection and Control Strategies

Aflatoxins produced by the Aspergillus species are highly toxic, carcinogenic, and cause severe contamination to food sources, leading to serious health consequences. Contaminations by aflatoxins have been reported in food and feed, such as groundnuts, millet, sesame seeds, maize, wheat, rice, fig, spices and cocoa due to fungal infection during pre- and post-harvest conditions. Besides these food products, commercial products like peanut butter, cooking oil and cosmetics have also been reported to be contaminated by aflatoxins. Even a low concentration of aflatoxins is hazardous for human and livestock. The identification and quantification of aflatoxins in food and feed is a major challenge to guarantee food safety. Therefore, developing feasible, sensitive and robust analytical methods is paramount for the identification and quantification of aflatoxins present in low concentrations in food and feed. There are various chromatographic and sensor-based methods used for the detection of aflatoxins. The current review provides insight into the sources of contamination, occurrence, detection techniques, and masked mycotoxin, in addition to management strategies of aflatoxins to ensure food safety and security.

Structure Elucidation and Toxicity Analysis of the Degradation Products of Deoxynivalenol by Gaseous Ozone

Fusarium Head Blight (FHB) or scab is a fungal disease of cereal grains. Wheat scab affects the yield and quality of wheat and produces mycotoxins such as deoxynivalenol (DON), which can seriously threaten human and animal health. In this study, gaseous ozone was used to degrade DON in wheat scab and the degradation products of ozonolysis were analyzed by ultra-performance liquid chromatography quadrupole-orbitrap mass spectrometry (UHPLC Q-Orbitrap). Toxicology analyses of the degradation products were also studied using structure-activity relationships. Ozone (8 mg L^-1 concentration) was applied to 2 μg mL^-1 of DON in ultrapure water, resulted in 95.68% degradation within 15 s. Ten ozonized products of DON in ultrapure water were analyzed and six main products (C₁₅H₁₈O₇, C₁₅H₁₈O₉, C₁₅H₂₂O₉, C₁₅H₂₀O₁₀, C₁₅H₁₈O_8, and C₁₅H₂₀O₉) were analyzed at varying concentrations of ozone and DON. Structural formulae were assigned to fragmentation products generated by MS² and Mass Frontier^® software. According to structure-activity relationship studies, the toxicities of the ozonized products were significantly decreased due to de-epoxidation and the attack of ozone at the C_9-10 double bond in DON. Based on the results of the study above, we can find that gaseous ozone is an efficient and safe technology to degrade DON, and these results may provide a theoretical basis for the practical research of detoxifying DON in scabby wheat and other grains.

Epigenetic alterations caused by aflatoxin b1: a public health risk in the induction of hepatocellular carcinoma

Aflatoxin B1 (AFB1) is currently the most commonly studied mycotoxin due to its great toxicity, its distribution in a wide variety of foods such as grains and cereals and its involvement in the development of + (hepatocellular carcinoma; HCC). HCC is one of the main types of liver cancer, and has become a serious public health problem, due to its high incidence mainly in Southeast Asia and Africa. Studies show that AFB1 acts in synergy with other risk factors such as hepatitis B and C virus leading to the development of HCC through genetic and epigenetic modifications. The genetic modifications begin in the liver through the biomorphic AFB1, the AFB1-exo-8.9-Epoxy active, which interacts with DNA to form adducts of AFB1-DNA. These adducts induce mutation in codon 249, mediated by a transversion of G-T in the p53 tumor suppressor gene, causing HCC. Thus, this review provides an overview of the evidence for AFB1-induced epigenetic alterations and the potential mechanisms involved in the development of HCC, focusing on a critical analysis of the importance of severe legislation in the detection of aflatoxins.

Cold Plasma for Effective Fungal and Mycotoxin Control in Foods: Mechanisms, Inactivation Effects, and Applications

Cold plasma treatment is a promising intervention in food processing to boost product safety and extend the shelf-life. The activated chemical species of cold plasma can act rapidly against micro-organisms at ambient temperatures without leaving any known chemical residues. This review presents an overview of the action of cold plasma against molds and mycotoxins, the underlying mechanisms, and applications for ensuring food safety and quality. The cold plasma species act on multiple sites of a fungal cell resulting in loss of function and structure, and ultimately cell death. Likewise, the species cause chemical breakdown of mycotoxins through various pathways resulting in degradation products that are known to be less toxic. We argue that the preliminary reports from cold plasma research point at good potential of plasma for shelf-life extension and quality retention of foods. Some of the notable food sectors which could benefit from antimycotic and antimycotoxin efficacy of cold plasma include, the fresh produce, food grains, nuts, spices, herbs, dried meat and fish industries.

Use of Cold Atmospheric Plasma to Detoxify Hazelnuts from Aflatoxins

Aflatoxins, produced by Aspergillus flavus and A. parasiticus, can contaminate different foodstuffs, such as nuts. Cold atmospheric pressure plasma has the potential to be used for mycotoxin detoxification. In this study, the operating parameters of cold atmospheric pressure plasma were optimized to reduce the presence of aflatoxins on dehulled hazelnuts. First, the effect of different gases was tested (N₂, 0.1% O₂ and 1% O₂, 21% O₂), then power (400, 700, 1000, 1150 W) and exposure time (1, 2, 4, and 12 min) were optimized. In preliminary tests on aflatoxin standard solutions, this method allowed to obtain a complete detoxification using a high power for a few minutes. On hazelnuts, in similar conditions (1000 W, 12 min), a reduction in the concentration of total aflatoxins and AFB₁ of over 70% was obtained. Aflatoxins B₁ and G₁ were more sensitive to plasma treatments compared to aflatoxins B₂ and G₂, respectively. Under plasma treatment, aflatoxin B₁ was more sensitive compared to aflatoxin G₁. At the highest power, and for the longest time, the maximum temperature increment was 28.9 °C. Cold atmospheric plasma has the potential to be a promising method for aflatoxin detoxification on food, because it is effective and it could help to maintain the organoleptic characteristics.

Effect of ozone treatment on deoxynivalenol and quality evaluation of ozonised wheat

Deoxynivalenol (DON) is the secondary metabolite of Fusarium graminearum, which is always found in Fusarium head blight of wheat. In this study, gaseous ozone was used to treat both DON solution and scabbed wheat to investigate the effectiveness of ozone treatment on DON degradation and the effect of ozone on the quality parameters of wheat. It was found that gaseous ozone had a significant effect on DON reduction in solution, when 10 mg l(-1) gaseous ozone was used to treat a 1 μg ml(-1) of DON solution, the degradation rate of DON was 93.6% within 30 s. Lower initial concentrations of DON solution treated with higher concentrations of ozone, and longer times showed higher DON degradation rates. Gaseous ozone was effective against DON in scabbed wheat. The degradation rate of DON increased with ozone concentration and processing time. The correlation between the time and degradation rate was y = -1.1926x(2) + 11.427x - 8.7787. In the process of ozone oxidation, a higher moisture content of wheat was more sensitive than that of lower moisture content to ozone under the same conditions. All samples were treated with different concentrations of ozone for 4 h to investigate the effect of ozone on wheat quality. No significant detrimental changes in the starch pasting properties of wheat were observed after all the samples were treated with ozone within 4 h. On the other hand, there was a slight rise in the dough development time and stability time, which meant the quality of flour improved after ozone treatment.