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Chromatography Techniques Shed Light on the Pervasive Toxins in Our Food Supply

A scientist with gloved hands using tweezers to pick up a sample of a dried bean from a selection of pots of pulses.
Credit: Chaiyan Anuwatmongkolchai / Pixabay.
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With greater scientific understanding and rising public awareness of health risks posed by food contaminants, the need to detect toxic molecules within our food supply swiftly and robustly has become increasingly pertinent. These risks are associated with a spectrum of hazards, ranging from mycotoxins and endogenous toxins to pesticides and excessive drug residues. A multi-institutional study led by Rey Juan Carlos University of Madrid explores the prevalence of toxic molecules in the food supply chain since 2020, investigating data from the Rapid Alert System for Food and Feed (RASFF). Published in Molecules, the research sheds light on the pervasive presence of natural toxins, environmental pollutants and food-processing contaminants. Reviewing chromatographic methods, particularly liquid chromatography (LC) and gas chromatography (GC), the findings underscore the necessity for enhanced analytical procedures to ensure food safety.

Efforts for increasing food safety: EU alerts on chemical contaminants

As food standards evolve in response to new information on the risks associated with contaminants, the food industry is increasingly adopting advanced analytical methods to ensure compliance. Chromatography has emerged as a leading analytical approach to examine molecules and other substances in food products resulting from agricultural treatments, production processes and packaging materials. The European Union (EU) coordinated the RASFF to increase accessibility to the findings of this analysis on food safety systematically. The current study aimed to review these food alerts in the EU from the last several years in an effort to identify the primary chemical contaminants prompting the notifications and to raise awareness for how these health risks are detected.

Pesticide residues and mycotoxins dominate EU food alerts

Using the RASFF database to analyze food alerts in the EU from January 2020 to June 2023, this study focused on abiotic organic chemical contaminants. Filters were applied to identify relevant alerts in hazard categories related to contaminants, biotoxins, chemical contamination, environmental pollutants, industrial contaminants, mycotoxins, natural toxins, pesticide residues and residues of veterinary medicinal products. Once collected, data were processed using Microsoft Excel to identify the primary compounds responsible for the alerts. Additionally, the researchers used Google Scholar and PubMed databases to conduct a review of chromatographic techniques used to detect these compounds in food samples, focusing on articles published in the last five years and limited to those written in English and appearing in peer-reviewed journals.

The key findings of the paper were:

  • Almost 60% of the total food alerts were issued due to the occurrence of pesticide residues, and 29% due to the presence of mycotoxins; toxic compounds naturally produced by fungi that thrive under specific temperature and humidity conditions.
  • Classified based on their chemical structure, organophosphorus pesticides, notably chlorpyrifos and dimethoate, were prominent in recent food alerts.
  • Mycotoxins, specifically, aflatoxins (B1, B2, G1, G2, M1 and M2), ochratoxin A, patulin and fusarium toxins (fumonisins, deoxynivalenol, T-2 toxin, HT-2 toxin and zearalenone) were common mycotoxins reported in recent food alerts. Consumption resulted in varying effects from acute gastrointestinal issues to more severe long-term health complications such as nephrotoxicity, hepatotoxicity, carcinogenicity, genotoxicity and mutagenicity.
  • Methods combining multidimensional (MD) chromatography and LC have become increasingly popular for separating non-volatile analytes from complex matrices, providing increased selectivity and sensitivity compared to conventional one-dimensional LC.
  • Micellar LC was shown — after rigorous evaluation with three tools; the Green Analytical Procedure Index (GAPI), National Environmental Method Index (NEMI) and Analytical Eco-Scale — to offer an environmentally friendly approach to contaminant detection in food, requiring minimal organic modifiers and offering easy recycling of the mobile phase, reducing the use of excess solvents.

Advancements in analytical tools for detecting the sources and risks of abiotic contaminants in food

Unexpected substances detected in food samples often fall into categories such as agrochemicals used in food production, veterinary drugs found in animal-derived foods and organic contaminants from the environment. At any stage, improper food storage increases the risk of contamination by mycotoxins – secondary metabolites naturally produced by several species of mold, such as Aspergillus, Penicillium and Fusarium. The abiotic chemical contaminants found in foods at various stages of production, processing and transportation are highlighted by the findings of this study and underline the need for careful monitoring.

While the review underscored the prominence of LC in detecting contaminants, continuous advancements in extraction methods, such as employing molecularly imprinted polymers and magnetic solid-phase extraction, are revolutionizing toxin detection. The findings also shed light on emerging trends like MD chromatography and portable chromatography solutions, which aim to enhance the efficiency and sensitivity of food safety analysis. The push for advancements in chromatographic techniques reflect the growing importance of identifying and quantifying food contaminants and residues for enhanced food safety.

Monitoring systems and regulations paired with advancements in chromatography pave the way for enhanced contaminant detection, thereby facilitating more informed food recalls and improved food safety for consumers. The development of large-scale multiresidue methods have streamlined the detection process by enabling analysis for numerous compounds simultaneously. Further, more environmentally friendly approaches, such as micellar liquid chromatography, underscores a commitment to more sustainable analytical practices. These findings collectively represent a step forward in safeguarding food safety and public health while promoting environmental responsibility in analytical methodologies. 

It is important to note that this review concentrated on alerts concerning abiotic chemical contaminants, excluding alerts associated with other types of contaminants or hazards in food products. Additionally, while the aim was to offer a comprehensive overview of chromatographic techniques for detecting chemical compounds in food samples, the scope was restricted to articles published in English and peer-reviewed journals within the past five years. Consequently, it is possible that relevant studies published in other languages or in non-peer-reviewed sources might have been overlooked.

Improving food safety through chromatographic innovations

Future research should aim to broaden the scope of food safety studies to compare a wider array of contaminants and toxins, beyond abiotic chemical contaminants alone. Efforts should focus on overcoming language and publication biases by including studies published in languages other than English and in non-peer-reviewed sources. There is also a need for continued monitoring of innovation in chromatographic techniques for contaminant detection and analysis in food samples. Moreover, interdisciplinary collaborations and advancements in technology could further advance our understanding of food safety issues and improve detection methods. One avenue for future research involves a closer examination of the advancement of large-scale multiresidue methods, focusing on their potential to enhance sensitivity, specificity and efficiency in detecting contaminants. Additionally, a crucial direction for investigation is the implementation of environmentally friendly techniques, which can further contribute to sustainable and responsible practices in the food industry.

Reference: Casado N, Berenguer CV, Câmara JS, Pereira JA. What are we eating? Surveying the presence of toxic molecules in the food supply chain using chromatographic approaches. Molecules. 2024;29(3):579. doi:10.3390/molecules29030579