Perspective on Advancing FDA Regulatory Monitoring for Mycotoxins in Foods using Liquid Chromatography and Mass Spectrometry (Review)

The screening method for 39 phytotoxins and mycotoxins in blood and urine with liquid chromatography-high resolution mass spectrometry

BACKGROUND

Poisonings caused by plant toxins and mycotoxins occur frequently, which do great harm to human health and social public health safety. When a poisoning incident occurs, biological samples are commonly be used to conduct the detection of toxic substances and their metabolites for targeted clinical treatment and incident analysis.

OBJECTIVE

To establish an efficient and accurate analysis method of 39 phytotoxins and mycotoxins in blood and urine by high performance liquid chromatography quadrupole tandem orbitrap mass spectrometry (HPLC-Orbitrap MS).

METHOD

After 3 mL of methanol being added to 1 mL blood and urine respectively for extraction and protein precipitation, the supernatant was injected into HPLC-Orbitrap MS for analysis. The phytotoxins and mycotoxins were separated by Hypersil GOLD PFP column with gradient elution using methanol-5 mmol/L ammonium acetate as mobile phase. The data were collected in ESI positive ion mode using Full MS/dd-MS2 for mass spectrometry detection.

RESULT

The mass database of 39 phytotoxins and mycotoxins was developed, and accurate qualitative analysis can be obtained by matching with the database using the proposed identification criteria. Limit of detections (LODs) were 1.34 × 10-4 ∼ 1.92 ng/mL and 1.92 × 10-4 ∼ 9.80 ng/mL for blood and urine samples, respectively. Limits of quantification (LOQ) of toxins in blood and urine ranged from 4.47 × 10-4 ∼ 6.32 ng/mL and 6.39 × 10-4 ∼ 32.67 ng/mL, respectively. Intra-day relative standard deviations (RSDs) were 0.79 % ∼ 10.90 %, and inter-day RSDs were 1.08 % ∼ 18.93 %. The recoveries can reach 90 % ∼ 110 % with matrix matching calibration curves.

CONCLUSION

The established method is simple and rapid to operate, which can complete the sample analysis within 30 min, providing technical support for clinical poisoning treatment and public health poisoning analysis.

Challenges and Future State for Mycotoxin Analysis: A Review From a Regulatory Perspective

Mycotoxins are naturally occurring toxins produced by certain fungi. Exposure to mycotoxins may occur through the consumption of contaminated foods or from animals that are fed contaminated feed. To safeguard the nation's food supply, the U.S. Food and Drug Administration (FDA) utilizes a comprehensive mycotoxin program which samples and analyzes foods for surveillance and compliance purposes, including enforcing action levels. Mycotoxin analysis is at the center of the mycotoxin program, as concentration data are needed for data analysis, scientific assessments, and risk management. This review focuses on the Agency's continuous efforts to develop and incorporate fit-for-purpose analytical tools for mycotoxin analysis with particular focus on the relationship between analytical methodologies and scientific assessments. The discussion further highlights challenges and advancements in analytical methods and discusses future possibilities to develop analytical tools and preventative risk management approaches to meet the evolving regulatory needs.

Soil Aspergillus Species, Pathogenicity and Control Perspectives

Five Aspergillus sections have members that are established agricultural pests and producers of different metabolites, threatening global food safety. Most of these pathogenic Aspergillus species have been isolated from almost all major biomes. The soil remains the primary habitat for most of these cryptic fungi. This review explored some of the ecological attributes that have contributed immensely to the success of the pathogenicity of some members of the genus Aspergillus over time. Hence, the virulence factors of the genus Aspergillus, their ecology and others were reviewed. Furthermore, some biological control techniques were recommended. Pathogenic effects of Aspergillus species are entirely accidental; therefore, the virulence evolution prediction model in such species becomes a challenge, unlike their obligate parasite counterparts. In all, differences in virulence among organisms involved both conserved and species-specific genetic factors. If the impacts of climate change continue, new cryptic Aspergillus species will emerge and mycotoxin contamination risks will increase in all ecosystems, as these species can metabolically adjust to nutritional and biophysical challenges. As most of their gene clusters are silent, fungi continue to be a source of underexplored bioactive compounds. The World Soil Charter recognizes the relevance of soil biodiversity in supporting healthy soil functions. The question of how a balance may be struck between supporting healthy soil biodiversity and the control of toxic fungi species in the field to ensure food security is therefore pertinent. Numerous advanced strategies and biocontrol methods so far remain the most environmentally sustainable solution to the control of toxigenic fungi in the field.

Detection of T-2 Toxin in Wheat and Maize with a Portable Mass Spectrometer

T-2 toxin is a mycotoxin routinely found as a contaminant of cereal grains worldwide. A portable mass spectrometer was adapted to enable the detection of T-2 toxin in wheat and maize by APCI-MS. In order to facilitate rapid testing, a rapid cleanup was used. The method was able to detect T-2 toxin in soft white wheat, hard red wheat, and yellow dent maize and could be used to screen for T-2 at levels above 0.2 mg/kg. The HT-2 toxin was only detectable at very high levels (>0.9 mg/kg). Based on these results, the sensitivity was not sufficient to allow the application of the screening method to these commodities at levels recommended by the European Commission. With a cut-off level of 0.107 mg/kg, the method correctly classified nine of ten reference samples of wheat and maize. The results suggest that portable MS detection of T-2 toxin is feasible. However, additional research will be needed to develop an application sensitive enough to meet regulatory requirements.

Opinion: Multi-Mycotoxin Reference Materials

The analysis of mycotoxins in food and feed using liquid chromatography coupled with mass spectrometry is considered advantageous because the hyphenated technology enables simultaneous determination of multiple mycotoxins. Multi-mycotoxin analysis requires special consideration of quality control parameters to ensure proper evaluation of data quality for all target mycotoxins in method development and routine sample analysis. Mycotoxin matrix reference materials, especially certified reference materials, are stable and homogeneous matrices with certified traceability, concentrations, and uncertainty for mycotoxin(s) of interest. The use of these reference materials for single mycotoxin analysis has been a well-accepted practice and should be extended to multi-mycotoxin analysis. This opinion piece discusses the following essential metrological and operational components to improve data quality: (1) purposes of multi-mycotoxin reference materials; (2) comparison of reference materials, certified reference materials, and in-house quality control materials; (3) advantages of using reference materials for multi-mycotoxin analysis; (4) current trends and challenges of multi-mycotoxin reference materials. Potential applications of reference materials discussed here can improve routine mycotoxin determination and will lead to better accuracy and consistency of results. Quality control processes that incorporate reference materials in the field of mycotoxin analysis ensure successful development and implementation of liquid chromatography mass spectrometry-based multi-mycotoxin methods.

Mycotoxin detoxification of food by lactic acid bacteria

Today, a few hundred mycotoxins have been identified and the number is rising. Mycotoxin detoxification of food and feed has been a technically uphill task for the industry. In the twenty-first century, the public demand is healthy food with minimum use of chemicals and preservatives. Among all the fungal inhibition and mycotoxin detoxification methods so far developed for food, biopreservation and biodetoxification have been found safe and reliable. Nowadays, lactic acid bacteria (LAB) are of great interest as biological additives in food owing to their Generally Recognized as Safe (GRAS) classification and mycotoxin detoxification capability. The occurrence of fungul growth in the food chain can lead to health problems such as mycotoxicosis and cancer to humans due to producing mycotoxins such as aflatoxins. Biopreservation is among the safest and most reliable methods for inhibition of fungi in food. This review highlights the great potential of LAB as biodetoxificant by summarizing various reported detoxification activities of LAB against fungal mycotoxins released into foods. Mechanisms of mycotoxin detoxification, also the inherent and environmental factors affecting detoxifying properties of LAB are also covered.

Detection, Contamination, Toxicity, and Prevention Methods of Ochratoxins: An Update Review

Ochratoxins (OTs) with nephrotoxic, immunosuppressive, teratogenic, and carcinogenic properties are thermostable fungal subordinate metabolites. OTs contamination can occur before or after harvesting, during the processing, packing, distribution, and storage of food. Mold development and mycotoxin contamination can occur in any crop or cereal that has not been stored properly for long periods of time and is subjected to high levels of humidity and temperature. Ochratoxin A (OTA) presents a significant health threat to creatures and individuals. There is also a concern of how human interaction with OTA will also express the remains of OTA from feedstuffs into animal-derived items. Numerous approaches have been studied for the reduction of the OTA content in agronomic products. These methods can be classified into two major classes: inhibition of OTA adulteration and decontamination or detoxification of food. A description of the various mycotoxins, the organism responsible for the development of mycotoxins, and their adverse effects are given. In the current paper, the incidence of OTA in various fodder and food materials is discussed, which is accompanied by a brief overview of the OTA mode of synthesis, physicochemical properties, toxic effects of various types of ochratoxins, and OTA decontamination adaptation methods. To our knowledge, we are the first to report on the structure of many naturally accessible OTAs and OTA metabolism. Finally, this paper seeks to be insightful and draw attention to dangerous OTA, which is too frequently neglected and overlooked in farm duplication from the list of discrepancy studies.

Efficacy of lactic acid bacteria supplementation against Fusarium graminearum growth in vitro and inhibition of Zearalenone causing inflammation and oxidative stress in vivo

Fusarium graminearum invasion and Zearalenone (ZEN)-mycotoxin contamination are considered the most global threat to food and feed. This study investigates the effect Lactobacillus plantarum MON03 viable cells (LPVC) and LP free cells supernatant (LPFCS) against Fusarium graminearum growth and ZEN production in vitro and evaluates if treatment with LP viable cells can counteract the negative effect of ZEN on inflammation and oxidative stress in mesenteric lymph nodes and serum biochemical parameters in mice. For the in vitro study, 7 days of LPVC, LPFCS and F. graminearum co-incubation at different concentrations was done in order to determine the antifungal activity and ZEN- production inhibition. Regarding the in vivo study, Balb/c mice were treated as following: Control, ZEN group, LP group and ZEN + LP group for 30 days. In vitro, LPVC showed an excellent antifungal activity after 7 days of co-incubation (10³ CFU/ml). LPVC was succeeded also to inhibit ZEN production by the fungi. In vivo, ZEN has shown an important oxidative damage. As a result of the exposure to ZEN, an increase cytokines, as effectors of an inflammatory response, were observed in the mesenteric lymph nodes (MLN) of intoxicated mice. In parallel, a serum biochemical change was also observed. LPVC induced a reduction of ZEN-induced oxidative stress and counteracts also the biochemical parameters damage and the inflammatory markers increased by ZEN. LPVC can be valorized as an anti-cating agent in the vitro and in the gastro-intestinal tract to decrease ZEN-toxic effects.

Advancing the FDA/Office of Regulatory Affairs Mycotoxin Program: New Analytical Method Approaches to Addressing Needs and Challenges

The U.S. Food and Drug Administration (FDA), Office of Regulatory Affairs (ORA) oversees FDA field laboratories, monitoring the occurrence and levels of toxic mycotoxins in domestic and imported human and animal food products that have the potential to impact human and animal health when consumed. The mycotoxins being routinely monitored in human and animal foods and feeds by the Agency include aflatoxins (B1, B2, G1, G2, and M1), fumonisins (FB1, FB2, and FB3), deoxynivalenol, ochratoxin A, patulin, and zearalenone. There has been an ongoing expansion of the Sample Collection Operation Planning Effort (SCOPE) for the mycotoxin program to monitor more mycotoxins in a wider variety of food and feed matrices. To meet this pressing need, we are in the process of modernizing and harmonizing the FDA/ORA mycotoxin program in the field laboratories using approaches such as adopting new analytical technologies/methods to further advance the service. This short perspective gives an overview of the FDA mycotoxin program in the field laboratories and the current program status, discusses the need to advance the program, strategies for modernization and harmonization by implementing liquid chromatography-mass spectrometry technologies for multi-mycotoxin analysis, benefits of doing this, and challenges in taking this new approach. Perspectives on finding solutions to tackle challenges and addressing emerging issues are also discussed.

Aflatoxins: History, Significant Milestones, Recent Data on Their Toxicity and Ways to Mitigation

In the early 1960s the discovery of aflatoxins began when a total of 100,000 turkey poults died by hitherto unknown turkey "X" disease in England. The disease was associated with Brazilian groundnut meal affected by Aspergillus flavus. The toxin was named Aspergillus flavus toxin-aflatoxin. From the point of view of agriculture, aflatoxins show the utmost importance. Until now, a total of 20 aflatoxins have been described, with B1, B2, G1, and G2 aflatoxins being the most significant. Contamination by aflatoxins is a global health problem. Aflatoxins pose acutely toxic, teratogenic, immunosuppressive, carcinogenic, and teratogenic effects. Besides food insecurity and human health, aflatoxins affect humanity at different levels, such as social, economical, and political. Great emphasis is placed on aflatoxin mitigation using biocontrol methods. Thus, this review is focused on aflatoxins in terms of historical development, the principal milestones of aflatoxin research, and recent data on their toxicity and different ways of mitigation.

A Review: Sample Preparation and Chromatographic Technologies for Detection of Aflatoxins in Foods

As a class of mycotoxins with regulatory and public health significance, aflatoxins (e.g., aflatoxin B1, B2, G1 and G2) have attracted unparalleled attention from government, academia and industry due to their chronic and acute toxicity. Aflatoxins are secondary metabolites of various Aspergillus species, which are ubiquitous in the environment and can grow on a variety of crops whereby accumulation is impacted by climate influences. Consumption of foods and feeds contaminated by aflatoxins are hazardous to human and animal health, hence the detection and quantification of aflatoxins in foods and feeds is a priority from the viewpoint of food safety. Since the first purification and identification of aflatoxins from feeds in the 1960s, there have been continuous efforts to develop sensitive and rapid methods for the determination of aflatoxins. This review aims to provide a comprehensive overview on advances in aflatoxins analysis and highlights the importance of sample pretreatments, homogenization and various cleanup strategies used in the determination of aflatoxins. The use of liquid-liquid extraction (LLE), supercritical fluid extraction (SFE), solid phase extraction (SPE) and immunoaffinity column clean-up (IAC) and dilute and shoot for enhancing extraction efficiency and clean-up are discussed. Furthermore, the analytical techniques such as gas chromatography (GC), liquid chromatography (LC), mass spectrometry (MS), capillary electrophoresis (CE) and thin-layer chromatography (TLC) are compared in terms of identification, quantitation and throughput. Lastly, with the emergence of new techniques, the review culminates with prospects of promising technologies for aflatoxin analysis in the foreseeable future.

Retrospective and Prospective Look at Aflatoxin Research and Development from a Practical Standpoint

Among the array of structurally and toxicologically diverse mycotoxins, aflatoxins have attracted the most interest of scientific research due to their high toxicity and incidence in foods and feeds. Despite the undeniable progress made in various aspects related to aflatoxins, the ultimate goal consisting of reducing the associated public health risks worldwide is far from being reached due to multiplicity of social, political, economic, geographic, climatic, and development factors. However, a reasonable degree of health protection is attained in industrialized countries owing to their scientific, administrative, and financial capacities allowing them to use high-tech agricultural management systems. Less fortunate situations exist in equatorial and sub-equatorial developing countries mainly practicing traditional agriculture managed by smallholders for subsistence, and where the climate is suitable for mould growth and aflatoxin production. This situation worsens due to climatic change producing conditions increasingly suitable for aflatoxigenic mould growth and toxin production. Accordingly, it is difficult to harmonize the regulatory standards of aflatoxins worldwide, which prevents agri-foods of developing countries from accessing the markets of industrialized countries. To tackle the multi-faceted aflatoxin problem, actions should be taken collectively by the international community involving scientific research, technological and social development, environment protection, awareness promotion, etc. International cooperation should foster technology transfer and exchange of pertinent technical information. This review presents the main historical discoveries leading to our present knowledge on aflatoxins and the challenges that should be addressed presently and in the future at various levels to ensure higher health protection for everybody. In short, it aims to elucidate where we come from and where we should go in terms of aflatoxin research/development.

The enzymatic detoxification of the mycotoxin deoxynivalenol: identification of DepA from the DON epimerization pathway

The biological detoxification of mycotoxins, including deoxynivalenol (DON), represents a very promising approach to address the challenging problem of cereal grain contamination. The recent discovery of Devosia mutans 17-2-E-8 (Devosia spp. 17-2-E-8), a bacterial isolate capable of transforming DON to the non-toxic stereoisomer 3-epi-deoxynivalenol, along with earlier reports of bacterial species capable of oxidizing DON to 3-keto-DON, has generated interest in the possible mechanism and enzyme(s) involved. An understanding of these details could pave the way for novel strategies to manage this widely present toxin. It was previously shown that DON epimerization proceeds through a two-step biocatalysis. Significantly, this report describes the identification of the first enzymatic step in this pathway. The enzyme, a dehydrogenase responsible for the selective oxidation of DON at the C3 position, was shown to readily convert DON to 3-keto-DON, a less toxic intermediate in the DON epimerization pathway. Furthermore, this study provides insights into the PQQ dependence of the enzyme. This enzyme may be part of a feasible strategy for DON mitigation within the near future.

Development of a LC-MS/MS Method for the Multi-Mycotoxin Determination in Composite Cereal-Based Samples

The analytical scenario for determining contaminants in the food and feed sector is constantly prompted by the progress and improvement of knowledge and expertise of researchers and by the technical innovation of the instrumentation available. Mycotoxins are agricultural contaminants of fungal origin occurring at all latitudes worldwide and being characterized by acute and chronic effects on human health and animal wellness, depending on the species sensitivity. The major mycotoxins of food concern are aflatoxin B1 and ochratoxin A, the first for its toxicity, and the second for its recurrent occurrence. However, the European legislation sets maximum limits for mycotoxins, such as aflatoxin B1, ochratoxin A, deoxynivalenol, fumonisins, and zearalenone, and indicative limits for T-2 and HT-2 toxins. Due to the actual probability that co-occurring mycotoxins are present in a food or feed product, nowadays, the availability of reliable, sensitive, and versatile multi-mycotoxin methods is assuming a relevant importance. Due to the wide range of matrices susceptible to mycotoxin contamination and the possible co-occurrence, a multi-mycotoxin and multi-matrix method was validated in liquid chromatography-tandem mass spectrometry (LC-MS/MS) with the purpose to overcome specific matrix effects and analyze complex cereal-based samples within the Italian Total Diet Study project.

Developments in mycotoxin analysis: an update for 2015-2016

This review summarises developments in the determination of mycotoxins over a period between mid-2015 and mid-2016. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed liquid chromatography mass spectrometry based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of presented methodologies.