IMS and the safety of festive foods

Author: Tim Jenkins,
Director of Food & Environmental, Global Markets

Many festivities come together at this time of year and one of the things they have in common is enormous quantities of food. Indeed, an estimated 1.76 billion candy canes and 22 million turkeys are consumed throughout this time period in the US alone. [1] With such vast quantities, it can be difficult to imagine the work that must go on behind the scenes to manage the complexity of this supply chain. The huge increase in demand during the holiday season, however, can make it difficult to trace the source of many food items and determine their safety. Exacerbating the issue, the food supply chain is increasingly international, with foodstuffs appearing at festive dinner tables from a myriad of sources worldwide. [2] As a consequence of these complicating factors, statistics from 2017-2018 suggest a 60% increase in food fraud over the holidays. [3]

The problem of food adulteration is not new, having roots deep in history. Housewives turned detective in Victorian-era London, uncovering widespread use of adulterants such as chalk in bread to improve whiteness. [4] In the UK, thorough investigation in the 1850s led to the introduction of legislation to ensure quality control, prompting the evolution of analytical methods to enforce it. [4] In today’s global market, however, a cooperative international effort is required to keep food safe. As a result, it is critical that sophisticated analytical methodologies and processes are in place at all points of the food supply chain. [2]

Ion mobility spectrometry (IMS) has emerged as one such analytical technique, working to both keep food safe and ensure its quality. [5] 

IMS for food analysis applications

When interfaced with liquid/gas chromatography (LC/GC) or ambient ionization, IMS coupled with mass spectrometry (MS) offers numerous benefits for food analysis studies. Operating on the millisecond timescale, IMS can improve selectivity by providing an additional dimension of separation, allowing differentiation of isomeric and isobaric species. As food often has a complex chemical make-up, this is highly useful. The technology can also improve method sensitivity by reducing chemical noise, and by providing collision cross section (CCS) data IMS can clarify and corroborate MS findings. As a result of these unique benefits, the use of IMS-MS for food analysis is only expected to grow in coming years. [5]

Maintaining a secure global food supply chain

Over the holiday period, many shoppers hunt around for the best deals. This can tempt some suppliers to break the law by adulterating food with cheaper alternatives to bring down costs and increase profits. [6] To prevent adulterated food from reaching consumers, it is immediately evident why analytical technologies capable of detecting fraudulent substances in complex samples are in such high demand. However, the field of food analysis encompasses more than simply detecting food fraud, further assessing the impact of diet on human health, the nutritional value of foodstuffs, and detection of a wide range of accidental contaminants. These can include pesticides, veterinary drugs, toxins, and pollutants. It can be seen that food analysis is a broad area, requiring the investigation of a wide range of compounds with different chemical relevance. [5]

Consequently, following the commercialization of the technology, there has been increasing interest in the application of IMS for food analysis. IMS works rapidly as a standalone technique, ionising and separating complex mixtures in the gas phase to provide information on the identity and concentration of targeted constituents. 

Increasingly, however, the spotlight is on how IMS can be coupled with MS to increase peak capacity and confidence in identification. While the technology is more widely known for its use in ‘omics’ studies, IMS-MS is increasingly making a name for itself in the field of food analysis. [5] IMS has been successfully used to monitor a variety of foodstuffs, including many common festive foods such as wine, hard cheeses and spice mixtures. [7] By measuring CCS values with IMS, researchers are provided with additional molecular information that characterises each ion. This can serve to greatly simplify analysis and aid compound identification. [5]

Food pesticide analysis

When thinking of all the delicious vegetable dishes on our festive dinner tables, pesticide residue is probably the last thing on our minds. It is known, however, that pesticide toxicity can cause both acute and chronic health problems in humans, prompting the World Health Organisation to establish strict limits on acceptable levels of pesticide residues in foods. [8] This has created a need for robust analytical methods that can accurately identify and quantify hundreds of different pesticides with diverse physicochemical properties within a complex sample. As pesticides generally exist as only a tiny fraction of the total mixture, they can easily be obscured by signals from more dominant components. [9]

Recognising this, a recent study leveraged travelling wave ion mobility-mass spectrometry to develop a rapid method for pesticide screening. By coupling to liquid chromatography and building up a reference library of CCS values corresponding to individual pesticides, researchers could fully exploit the power of the technology. The screening was highly successful, facilitating the confident identification of pesticides by comparing measured CCS with reference CCS data. The results were impressively consistent, differing by no more than 1% from the reference data library. [9] This study highlights the immense potential of the technology for future studies, and underscores the value CCS data can lend to analyses.

Conclusion

With a global food supply chain opening up new opportunities for food fraud, and a spike in demand over the holidays, increasingly advanced analytical methods are required to ensure our food remains safe and authentic. IMS-MS has proved itself worthy of note for this purpose, offering rapid acquisition of CCS data to speed contaminant identification in complex mixtures. With the numerous benefits IMS-MS lends to the field, its use is only expected to grow. So, this holiday season, let’s all spare a thought as we tuck into our festive feasts for the incredible technologies working behind the scenes to keep our food safe, healthy and of good quality. 

References:

  1. https://www.delish.com/food/news/a38889/statistics-about-holiday-food/
  2. Opara LU. Traceability in agriculture and food supply chain: A review of basic concepts, technological implications, and future prospects. (2002) https://pdfs.semanticscholar.org/cae1/d33a81557fbc3791be0d3013f55796d2b6d8.pdf?_ga=2.238009283.2112963769.1576579162-967537433.1576579162
  3. https://www.retaildive.com/news/the-holidays-mean-higher-sales-and-more-fraud/540562/
  4. https://www.hillbrush.com/uk/About/News/The-Victorians-and-Modern-Day-Food-Legislation/
  5. Hernández-Mesa M, Ropartz D, García-Campaña AM, et al. Ion Mobility Spectrometry in Food Analysis: Principles, Current Applications and Future Trends. Molecules. 24 (15), 2019. 10.3390/molecules24152706
  6. https://www.foodmanufacture.co.uk/Article/2014/11/03/Christmas-food-fraud-threat-warns-expert
  7. Acre L, Valcarcel M. Chapter 9 – The Role of Ion Mobility Spectrometry to Support the Food Protected Designation of Origin. Comprehensive Analytical Chemistry, 60, 2013, 221-249. https://doi.org/10.1016/B978-0-444-59562-1.00009-8
  8. World Health Organization. Pesticide residues in food (2018). https://www.who.int/news-room/fact-sheets/detail/pesticide-residues-in-food
  9. Goscinny S, McCullagh M, Fae J, et al. Towards the use of ion mobility mass spectrometry derived collision cross section as a screening approach for unambiguous identification of targeted pesticides in food. Rapid Communications in Mass Spectrometry, 33 (S2), 2019, 34-48.  https://doi.org/10.1002/rcm.8395

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