Cytotoxicity of gamma irradiated aflatoxin B1 and ochratoxin A

Investigating the individual and mixture cytotoxicity of co-occurring aflatoxin B1, enniatin B, and sterigmatocystin on gastric, intestinal, hepatic, and renal cellular models

This study investigates the individual and combined effects of the mycotoxins, Aflatoxin B1 (AFB1), Enniatin B (ENNB) and Sterigmatocystin (STG), on the cellular viability of gastric (NCI-N87), intestinal (Caco-2), hepatic (Hep-G2) and renal (Hek-293) cells, shedding light on synergistic or antagonistic effects using a constant ratio combination design proposed by Chou-Talalay. These toxins are prevalent in cereal-based foods, frequently consumed by children which raises concerns about their exposure to these mycotoxins. This population is particularly vulnerable to the effects of these toxins due to their underdeveloped organs and incompletely structured physiological processes. Results showed that ENB was the most toxic of the three mycotoxins across all cell lines, while STG and AFB1 showed lower toxicity. The combination of ENNB + STG was found to be the most potent in terms of binary mixtures. In regard to ternary combinations, Caco-2 cells are more sensitive to the tested mycotoxins, whereas NCI-N87 cells show lower levels of cell damage. Worrying dose reduction values (>10-fold) were found for ENNB in binary and ternary combinations at low exposure levels. These findings are significant for establishing initial reference values, which play a pivotal role in estimating reference doses that are subsequently incorporated into the broader risk assessment process.

Evaluating the human neurotoxicity and toxicological interactions impact of co-occurring regulated and emerging mycotoxins

Mycotoxins can inflict harmful effects on diverse organs, and mounting evidence indicates their potential involvement in human neurodegenerative diseases. Given the common occurrence of these toxins in food, there is an increasing demand for a comprehensive assessment of their combined toxicity to enhance our understanding of their potential hazards. This research investigates mycotoxin exposure from widely consumed cereal-based products, including enniatin B (ENNB), sterigmatocystin (STG), aflatoxin B1 (AFB1), cyclopiazonic acid (CPZ), citrinin (CIT), and ochratoxin A (OTA). Employing the median-effect equation based on Chou and Talalay's mass-action law, we assessed their cytotoxicity in human SH-SY5Y neuronal cells. Notably, ENNB displayed the highest neurotoxicity (IC50 = 3.72 µM), followed by OTA (9.10 µM) and STG (9.99 µM). The combination of OTA + STG exhibited the highest toxicity (IC50 = 3.77 µM), while CPZ + CIT showed the least detrimental effect. Approximately 70 % of tested binary combinations displayed synergistic or additive effects, except for ENNB + STG, ENNB + AFB1, and CPZ + CIT, which showed antagonistic interactions. Intriguingly, the senary combination displayed moderate antagonism at the lowest exposure and moderate synergism at higher doses. OTA exhibited predominantly synergistic interactions, comprising approximately 90 %, a noteworthy finding considering its prevalence in food. Conversely, ENNB interactions tended to be antagonistic. The most remarkable synergy occurred in the STG and CIT combination, enabling a 50-fold reduction in CIT dosage for an equivalent toxic effect. These findings highlight the biological relevance of robust synergistic interactions, emphasizing the need to assess human exposure hazards accurately, particularly considering frequent mycotoxin co-occurrence in environmental and food settings.

Unraveling the Nrf2-ARE Signaling Pathway in the DF-1 Chicken Fibroblast Cell Line: Insights into T-2 Toxin-Induced Oxidative Stress Regulation

The T-2 toxin (T2) poses a major threat to the health and productivity of animals. The present study aimed to investigate the regulatory mechanism of Nrf2 derived from broilers against T2-induced oxidative damage. DF-1 cells, including those with normal characteristics, as well as those overexpressing or with a knockout of specific components, were exposed to a 24 h treatment of 50 nM T2. The primary objective was to evaluate the indicators associated with oxidative stress and the expression of downstream antioxidant factors regulated by the Nrf2-ARE signaling pathway, at both the mRNA and protein levels. The findings of this study demonstrated a noteworthy relationship between the up-regulation of the Nrf2 protein and a considerable reduction in the oxidative stress levels within DF-1 cells (p < 0.05). Furthermore, this up-regulation was associated with a notable increase in the mRNA and protein levels of antioxidant factors downstream of the Nrf2-ARE signaling pathway (p < 0.05). Conversely, the down-regulation of the Nrf2 protein was linked to a marked elevation in oxidative stress levels in DF-1 cells (p < 0.05). Additionally, this down-regulation resulted in a significant decrease in both the mRNA and protein expression of antioxidant factors (p < 0.05). This experiment lays a theoretical foundation for investigating the detrimental impacts of T2 on broiler chickens. It also establishes a research framework for employing the Nrf2 protein in broiler chicken production and breeding. Moreover, it introduces novel insights for the prospective management of oxidative stress-related ailments in the livestock and poultry industry.

Peppermint essential oil and its nano-emulsion: Potential against aflatoxigenic fungus Aspergillus flavus in food and feed

A facultative parasite called Aspergillus flavus contaminates several important food crops before and after harvest. In addition, the pathogen that causes aspergillosis infections in humans and animals is opportunistic. Aflatoxin, a secondary metabolite produced by Aspergillus flavus, is also carcinogenic and mutagenic, endangering human and animal health and affecting global food security. Peppermint essential oils and plant-derived natural products have recently shown promise in combating A. flavus infestations and aflatoxin contamination. This review discusses the antifungal and anti-aflatoxigenic properties of peppermint essential oils. It then discusses how peppermint essential oils affect the growth of A. flavus and the biosynthesis of aflatoxins. Several cause physical, chemical, or biochemical changes to the cell wall, cell membrane, mitochondria, and associated metabolic enzymes and genes. Finally, the prospects for using peppermint essential oils and natural plant-derived chemicals to develop novel antifungal agents and protect foods are highlighted. In addition to reducing the risk of aspergillosis infection, this review highlights the significant potential of plant-derived natural products and peppermint essential oils to protect food and feed from aflatoxin contamination and A. flavus infestation.

Current physical techniques for the degradation of aflatoxins in food and feed: Safety evaluation methods, degradation mechanisms and products

Aflatoxins are the most toxic natural mycotoxins discovered so far, posing a serious menace to the food safety and trading economy of the world, especially developing countries. How to effectively detoxify has persistently occupied a place on the list of "global hot-point" concerns. Among the developed detoxification methods, physical methods, as the authoritative techniques for aflatoxins degradation, could rapidly induce irreversible denaturation of aflatoxins. This review presents a brief overview of aflatoxins detection and degradation product structure identification methods. Four main safety evaluation methods for aflatoxins and degradation product toxicity assessment are highlighted combined with an update on research of aflatoxins decontamination in the last decade. Furthermore, the latest applications, degradation mechanisms and products of physical aflatoxin decontamination techniques including microwave heating, irradiation, pulsed light, cold plasma and ultrasound are discussed in detail. Regulatory issues related to "detoxification" are also explained. Finally, we put forward the challenges and future work in studying aflatoxin degradation based on the existing research. The purpose of supplying this information is to help researchers have a deeper understanding on the degradation of aflatoxins, break through the existing bottleneck, and further improve and innovate the detoxification methods of aflatoxins.

Remediation Strategies for Mycotoxins in Animal Feed

Mycotoxins occur widely in various animal feedstuffs, with more than 500 mycotoxins identified so far [...].

Deciphering the Hazardous Effects of AFB1 and T-2 Toxins: Unveiling Toxicity and Oxidative Stress Mechanisms in PK15 Cells and Mouse Kidneys

In China, animal feeds are frequently contaminated with a range of mycotoxins, with Aflatoxin B1 (AFB1) and T-2 toxin (T-2) being two highly toxic mycotoxins. This study investigates the combined nephrotoxicity of AFB1 and T-2 on PK15 cells and murine renal tissues and their related oxidative stress mechanisms. PK15 cells were treated with the respective toxin concentrations for 24 h, and oxidative stress-related indicators were assessed. The results showed that the combination of AFB1 and T-2 led to more severe cellular damage and oxidative stress compared to exposure to the individual toxins (p < 0.05). In the in vivo study, pathological examination revealed that the kidney tissue of mice exposed to the combined toxins showed signs of glomerular atrophy. The contents of oxidative stress-related indicators were significantly increased in the kidney tissue (p < 0.05). These findings suggest that the combined toxins cause significant oxidative damage to mouse kidneys. The study highlights the importance of considering the combined effects of mycotoxins in animal feed, particularly AFB1 and T-2, which can lead to severe nephrotoxicity and oxidative stress in PK15 cells and mouse kidneys. The findings have important implications for animal feed safety and regulatory policy.

Determination and detoxification of aflatoxin and ochratoxin in maize from different regions of Pakistan

The contamination of food commodities with mycotoxins could be a serious health threat to humans and animals. Therefore, identification, quantification and reduction of mycotoxins in food commodities, particularly of aflatoxins (AFs) and ochratoxin A (OTA) in grain foods, is essentially required to guarantee safe food. This study determined the levels of AFs and OTA in 135 maize grains samples belonging to eight salient maize varieties cultivated in Pakistan, and evaluated the usefulness of radiations and adsorbents to reduce their levels. High performance liquid chromatography (HPLC)-based method was validated for the determination of AFs and OTA in maize grains. The results showed that 69 and 61% samples were positive for AFs and OTA, respectively and 54 and 22% of the respective samples had AFs and OTA above the permissible limits set by Pakistan Standards and Quality Control Authority. The concentration of AFs, AFB1and OTA in grains ranged from 14.5 to 92.4, 1.02 to 2.46 and 1.41 to 53.9 μg kg^-1, respectively. Among the varieties, Pearl had the highest level of total AFs and OTA, whereas YH-5427 had the highest AFB1 level. The lowest concentration of AFs and OTA was found in Malaka and 30Y87, respectively. The use of 15 kGy gamma irradiation for 24 h, sunlight-drying for 20 h and UV irradiation for 12 h almost completely degraded the mycotoxins. The microwave heating for 120 s resulted in 9-33% degradation of mycotoxins. Moreover, the treatment of grains' extract with activated charcoal (5% w/w) removed > 96% of total AFs and AFB1, and up to 43% of OTA. The use of bentonite at the same rate removed OTA, total AFs and AFB1 by 93, 73 and 92%, respectively. Thus, it is concluded that contamination of maize grains with mycotoxins was fairly high in the collected maize grain samples in Pakistan, and treatment with radiations and adsorbents can effectively reduce mycotoxins contamination level in maize grains.

Aspergillus flavus and Aspergillus ochraceus inhibition and reduction of aflatoxins and ochratoxin A in maize by irradiation

Grains are susceptible to contamination by molds; some cause spoilage and others produce certain mycotoxins that cause a serious health threat to humans and animals. Aspergillus flavus and Aspergillus ochraceus and their mycotoxins, aflatoxins and ochratoxin A, are natural contaminants of various agricultural commodities. Control of these molds and their mycotoxins in food commodities is of utmost importance; therefore, the target of this research was to explore the effects of gamma irradiation doses on the growth of A. flavus and A. ochraceus in artificially inoculated yellow maize as well as on the production of aflatoxin B1, ochratoxin A, and the formation of toxins in maize. The irradiated dose of 6.0 kGy was found to completely inhibit the growth of the two molds, while a dose of 4.5 kGy reduced the production of their mycotoxins. Maximum degradation of the formed aflatoxins and ochratoxin A in maize occurred at 20 kGy, with best reduction rates of 40.1%, 33.3%, and 61.1% observed for aflatoxin B1, aflatoxin B2, and ochratoxin A, respectively. We recommend grains irradiation by gamma radiation at 6.0 kGy to decontaminate mycotoxin-producing molds before they produce mycotoxins. The study represents a proactive, efficient, and potent method for avoiding potential contamination of fungus during grains storage and transfer for one to two months.

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.

Incidence and exposure assessment of aflatoxins and ochratoxin A in Egyptian wheat

Aflatoxins and ochratoxin A occur frequently in grains and are associated with carcinogenic, and nephrotoxic properties. Therefore, the aim of this study was to determine the level of aflatoxins and ochratoxin A contamination in wheat samples obtained from different Egyptian governorates and to assess the effect of gamma irradiation on AFB₁ in spiked wheat samples, as well as to evaluate the estimated daily intake and hazard index. Thirty-six wheat grain samples purchased from different sale points were analyzed by High-Performance Liquid Chromatography. Data revealed that 33.33 % of the wheat grain samples were contaminated by aflatoxin B₁, whereas only 16.66 % of the wheat samples were above the maximum limits (2 μg/kg) set by the European Commission. Ochratoxin A was only detected in two wheat grain samples, and the results were considered below the maximum limit (5 μg/kg) set by the European Commission. On studying the effect of gamma irradiation on wheat samples spiked by aflatoxin B₁ (20 μg/kg), results revealed that aflatoxin B₁ was reduced to 1.22 and 0.94 μg/kg for samples gamma-irradiated at a dose of 10 and 20 KGy respectively. Estimated daily intake of ochratoxin A in wheat samples was found to be higher than that of the tolerable daily intake; however, hazard index values were below one, thus demonstrating no threat to human health.

Control of Foodborne Biological Hazards by Ionizing Radiations

Ionization radiations are used to ensure food safety and quality. This irradiation process uses ions of beta or gamma rays to inactivate or destroy the food spoilage pests, microorganisms and their toxins without significantly increasing the temperature of the treated product. Meanwhile, various intrinsic and extrinsic factors are involved in determining the efficacy of ionization irradiation against these organisms. Therefore, the dose of radiations is recommended according to the type of irradiation, substrate and microorganisms. However, controversies are surrounding the use of irradiations in the food industry due to a negative perception of irradiations. This manuscript described the use of ionization radiations to control the foodborne biological hazards and increase shelf life. Firstly, the characteristics and mode of action of irradiations were discussed. Secondly, the role of extrinsic and intrinsic factors influencing the radioresistance of biological hazards were elaborated. This literature review also detailed the differential effects of irradiations on different microorganisms and pests having a role in food safety and deterioration. Finally, the regulatory status and the consumer values along with the controversies surrounding the use of ionization irradiations in the food sector were explained.

Inhibitory Effects of Eurotium cristatum on Growth and Aflatoxin B1 Biosynthesis in Aspergillus flavus

Probiotic strain Eurotium cristatum was isolated from Chinese Fuzhuan brick-tea and tested for its in vitro activity against aflatoxigenic Aspergillus flavus. Results indicated that E. cristatum can inhibit the radial growth of A. flavus. Furthermore, this inhibition might be caused by E. cristatum secondary metabolites. The ability of culture filtrate of strain E. cristatum against growth and aflatoxin B₁ production by toxigenic A. flavus was evaluated in vitro. Meanwhile, the influence of filtrate on spore morphology of A. flavus was analyzed by scanning electron microscopy (SEM). Results demonstrated that both radial growth of A. flavus and aflatoxin B₁ production were significantly weakened following increases in the E. cristatum culture filtrate concentration. In addition, SEM showed that the culture filtrate seriously damaged hyphae morphology. Gas chromatography mass spectrometry (GC/MS) analysis of the E. cristatum culture supernatant revealed the presence of multiple antifungal compounds. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis showed that the expression of aflatoxin biosynthesis-related genes (aflD, aflQ, and aflS) were down-regulated. Importantly, this latter occurrence resulted in a reduction of the AflS/AflR ratio. Interestingly, cell-free supernatants of E. cristatum facilitated the effective degradation of aflatoxin B₁. In addition, two degradation products of aflatoxin B₁ lacking the toxic and carcinogenic lactone ring were identified. A toxicity study on the HepG2 cells showed that the degradation compounds were less toxic when compared with AFB₁.