Aflatoxins Contamination in Feed Commodities: From Occurrence and Toxicity to Recent Advances in Analytical Methods and Detoxification

Assessment of Alternaria Toxins and Pesticides in Organic and Conventional Tomato Products: Insights into Contamination Patterns and Food Safety Implications

Alternaria toxins (ATs) are a group of toxins produced by Alternaria fungi that frequently contaminate tomatoes and tomato products. Recently, the European Food Safety Authority evaluated ATs for their genotoxic and carcinogenic properties. Alternaria infestation is often controlled using ad hoc treatment strategies (fungicides). In this study, two analytical methods were developed, validated and applied for the determination of five ATs and 195 pesticides in tomato products collected from the Italian market. Two distinct groups, organic (n = 20) and conventional (n = 20) Italian tomato sauces, were characterized in depth. Tenuazonic acid, alternariol and alternariol monomethyl ether were found up to 517, 27 and 7.1 µg/kg, respectively, while pesticides were detected between 0.0026 and 0.0421 mg/kg in conventional products, and, interestingly, up to 0.0130 mg/kg in organic products. No correlation emerged between the detected levels of ATs and pesticides and the type of tomato cultivation, but the probability of pesticide contamination in conventional products was eight times higher than in organics. Some considerations about exposure assessment and risk characterization for ATs were also proposed in the overall population and in more sensitive and/or exposed subgroups, underlining the need for new focused toxicological and monitoring studies to establish reliable reference values. Moreover, these data highlight that fungicide treatments may not protect tomatoes from ATs contamination, although it may remove fungi infestation. As organic product consumption is increasing, it is important to lay down dedicated regulations for maximum permitted levels to ensure the food safety of these products that are often perceived by consumers as a healthier and environmentally friendlier choice.

The Role of AFB1, OTA, TCNs, and Patulin in Forensic Sciences: Applications in Autopsy, Criminal Investigations, and Public Health Prevention

Mycotoxins, specifically aflatoxin B1 (AFB1), ochratoxin A (OTA), trichothecenes (TCNs), and patulin, are a group of secondary metabolites that can contaminate food, leading to severe health implications for humans. Their detection and analysis within forensic toxicology are crucial, particularly as they can be implicated in cases of poisoning, foodborne illnesses, or lethal chronic exposure. However, little is known about the application that mycotoxins could have in forensic investigations and especially about the possibility of extracting and quantifying these molecules on tissues or post-mortem fluids collected at autopsy. We propose a review of the scientific literature on autopsy case studies in which the presence of mycotoxins on cadavers in cases of acute and chronic exposure has been investigated and identified. This review demonstrates how the analysis of mycotoxins on cadavers could be fundamental in the study of mushroom poisonings or even in the investigation of the chronic effects of mycotoxins on the human organism, by virtue of the known carcinogenic and mutagenic effects of many of them. This paper aims to explore the multifaceted role of mycotoxins within forensic sciences, focusing on their detection methods, implications in criminal contexts, and their potential as forensic evidence, thereby underscoring the critical importance they could assume in post-mortem toxicology, public health prevention, and forensic investigations.

Mycotoxins in Food: Cancer Risks and Strategies for Control

Mycotoxins are toxic compounds produced by fungi such as Aspergillus, Penicillium, and Fusarium, contaminating various food crops and posing severe risks to food safety and human health. This review discusses mycotoxins' origins, significance, and impact, particularly in relation to cancer risk. Major mycotoxins like aflatoxins, ochratoxins, fumonisins, zearalenone, and patulin are examined, along with their sources and affected foods. The carcinogenic mechanisms of these toxins, including their biochemical and molecular interactions, are explored, as well as epidemiological evidence linking mycotoxin exposure to cancer in high-risk populations. The review also highlights critical methodologies for mycotoxin detection, including HPLC, GC-MS, MS, and ELISA, and the sample preparation techniques critical for accurate analysis. Strategies for controlling mycotoxin contamination, both pre- and post-harvest, are discussed, along with regulations from organizations like the FAO and WHO. Current challenges in detection sensitivity, cost, and control effectiveness are noted. Future research is needed to develop innovative analytical techniques, improve control strategies, and address the influence of climate change on mycotoxin production. Finally, global collaboration and emerging technologies are essential for advancing mycotoxin control and enhancing food safety.

Characteristics of a Novel Zearalenone Lactone Hydrolase ZHRnZ and Its Thermostability Modification

Zearalenone (ZEN) is a toxic secondary metabolite produced by the Fusarium fungi, which widely contaminates grains, food, and feed, causing health hazards for humans and animals. Therefore, it is essential to find effective ZEN detoxification methods. Enzymatic degradation of ZEN is believed to be an eco-friendly detoxification strategy, specifically thermostable ZEN degradation enzymes are needed in the food and feed industry. In this study, a novel ZEN lactone hydrolase ZHRnZ from Rosellinia necatrix was discovered using bioinformatic and molecular docking technology. The recombinant ZHRnZ showed the best activity at pH 9.0 and 45 °C with more than 90% degradation for ZEN, α-zearalenol (α-ZOL), β-zearalenol (β-ZOL) and α-zearalanol (α-ZAL) after incubation for 15 min. We obtained 10 mutants with improved thermostability by single point mutation technology. Among them, mutants E122Q and E122R showed the best performance, which retained more than 30% of their initial activity at 50 °C for 2 min, and approximately 10% of their initial activity at 60 °C for 1 min. The enzymatic kinetic study showed that the catalytic efficiency of E122R was 1.3 times higher than that of the wild-type (WT). Comprehensive consideration suggests that mutant E122R is a promising hydrolase to detoxify ZEN in food and feed.

Biodegradation Characteristics and Mechanism of Aflatoxin B1 by Bacillus amyloliquefaciens from Enzymatic and Multiomics Perspectives

Aflatoxin B1 (AFB1), a mycotoxin and natural carcinogen, commonly contaminates cereals and animal feeds, posing serious health risks to human and animal. In this study, Bacillus amyloliquefaciens ZG08 isolated from kimchi could effectively remove 80.93% of AFB1 within 72 h at 37 °C and pH 7.0. Metabolome and transcriptome analysis showed that metabolic processes including glycerophospholipid metabolism and amino acid metabolism were most affected in B. amyloliquefaciens ZG08 exposed to AFB1. The adaptation mechanism likely involved activation of the thioredoxin system to restore intracellular redox equilibrium. The key genes, tpx and gldA, overexpressed in Escherichia coli BL21, achieved degradation rates of 60.15% and 47.16% for 100 μg/kg AFB1 under optimal conditions of 37 °C and pH 8.0 and 45 °C and pH 7.0, respectively. The degradation products, identified as AFD1, were less cytotoxic than AFB1 in HepG2 cells. These findings suggest potential strategies for utilizing probiotics and engineered enzymes in AFB1 detoxification.

Comprehensive Review of Aflatoxin and Ochratoxin A Dynamics: Emergence, Toxicological Impact, and Advanced Control Strategies

Filamentous fungi exhibit remarkable adaptability to diverse substrates and can synthesize a plethora of secondary metabolites. These metabolites, produced in response to environmental stimuli, not only confer selective advantages but also encompass potentially deleterious mycotoxins. Mycotoxins, exemplified by those originating from Alternaria, Aspergillus, Penicillium, and Fusarium species, represent challenging hazards to both human and animal health, thus warranting stringent regulatory control. Despite regulatory frameworks, mycotoxin contamination remains a pressing global challenge, particularly within cereal-based matrices and their derived by-products, integral components of animal diets. Strategies aimed at mitigating mycotoxin contamination encompass multifaceted approaches, including biological control modalities, detoxification procedures, and innovative interventions like essential oils. However, hurdles persist, underscoring the imperative for innovative interventions. This review elucidated the prevalence, health ramifications, regulatory paradigms, and evolving preventive strategies about two prominent mycotoxins, aflatoxins and ochratoxin A. Furthermore, it explored the emergence of new fungal species, and biocontrol methods using lactic acid bacteria and essential mustard oil, emphasizing their efficacy in mitigating fungal spoilage and mycotoxin production. Through an integrative examination of these facets, this review endeavored to furnish a comprehensive understanding of the multifaceted challenges posed by mycotoxin contamination and the emergent strategies poised to ameliorate its impact on food and feed safety.

Advancing Mycotoxin Detection in Food and Feed: Novel Insights from Surface-Enhanced Raman Spectroscopy (SERS)

The implementation of low-cost and rapid technologies for the on-site detection of mycotoxin-contaminated crops is a promising solution to address the growing concerns of the agri-food industry. Recently, there have been significant developments in surface-enhanced Raman spectroscopy (SERS) for the direct detection of mycotoxins in food and feed. This review provides an overview of the most recent advancements in the utilization of SERS through the successful fabrication of novel nanostructured materials. Various bottom-up and top-down approaches have demonstrated their potential in improving sensitivity, while many applications exploit the immobilization of recognition elements and molecular imprinted polymers (MIPs) to enhance specificity and reproducibility in complex matrices. Therefore, the design and fabrication of nanomaterials is of utmost importance and are presented herein. This paper uncovers that limited studies establish detection limits or conduct validation using naturally contaminated samples. One decade on, SERS is still lacking significant progress and there is a disconnect between the technology, the European regulatory limits, and the intended end-user. Ongoing challenges and potential solutions are discussed including nanofabrication, molecular binders, and data analytics. Recommendations to assay design, portability, and substrate stability are made to help improve the potential and feasibility of SERS for future on-site agri-food applications.

Microbial Composition of Water Kefir Grains and Their Application for the Detoxification of Aflatoxin B1

Water kefir grains (WKGs), the starter used to develop a traditional beverage named water kefir, consist of a symbiotic mixture of probiotics with diverse bioactivities, but little is known about their abilities to remove mycotoxins that have serious adverse effects on humans and animals. This study investigated the ability of WKGs to remove aflatoxin B1 (AFB1), one of the most toxic mycotoxins, under different settings, and determined the mechanism of absorption mediated by WKGs and the effect of WKGs on the toxicity induced by AFB1 and the reduction in AFB1 in cow milk and tea soups. The results showed the WKGs used herein were dominated by Lactobacillus, Acetobacter, Phenylobacterium, Sediminibacterium, Saccharomyces, Issatchenkia, and Kodamaea. HPLC analysis demonstrated that the WKGs effectively removed AFB1 at concentrations ranging from 1 to 5 µg/mL, pH values ranging from 3 to 9, and temperatures ranging from 4 to 45 °C. Additionally, the removal of AFB1 mainly depended on absorption, which was consistent with the Freundlich and pseudo-second-order kinetic models. Moreover, only 49.63% of AFB1 was released from the AFB1-WKG complex after four washes when the release of AFB1 was non-detectable. Furthermore, WKG treatment caused a dramatic reduction in the mutagenicity induced by AFB1 according to an Ames test and reduced more than 54% of AFB1 in cow milk and three tea soups. These results suggested that WKGs can act as a potential bio-absorbent with a high binding ability to detoxify AFB1 in food and feed via a chemical action step and multi-binding sites of AFB1 absorption in a wide range of scenarios.

Recombinant Oxidase from Armillaria tabescens as a Potential Tool for Aflatoxin B1 Degradation in Contaminated Cereal Grain

Forage grain contamination with aflatoxin B1 (AFB1) is a global problem, so its detoxification with the aim of providing feed safety and cost-efficiency is still a relevant issue. AFB1 degradation by microbial enzymes is considered to be a promising detoxification approach. In this study, we modified an previously developed Pichia pastoris GS115 expression system using a chimeric signal peptide to obtain a new recombinant producer of extracellular AFB1 oxidase (AFO) from Armillaria tabescens (the yield of 0.3 g/L), purified AFO, and selected optimal conditions for AFO-induced AFB1 removal from model solutions. After a 72 h exposure of the AFB1 solution to AFO at pH 6.0 and 30 °C, 80% of the AFB1 was degraded. Treatments with AFO also significantly reduced the AFB1 content in wheat and corn grain inoculated with Aspergillus flavus. In grain samples contaminated with several dozen micrograms of AFB1 per kg, a 48 h exposure to AFO resulted in at least double the reduction in grain contamination compared to the control, while the same treatment of more significantly (~mg/kg) AFB1-polluted samples reduced their contamination by ~40%. These findings prove the potential of the tested AFO for cereal grain decontamination and suggest that additional studies to stabilize AFO and improve its AFB1-degrading efficacy are required.