Proving the origin, authenticity and quality of food and beverage products is big business. Adulteration and fraudulent labeling of a foodstuff’s origin costs the global food industry an estimated $10 to $15 billion per year.
Food and beverage fraud and adulteration is not a new phenomenon. In Europe during the Middle Ages, high value imported spices were often combined with cheap substitutes such as ground nutshells, seeds, juniper berries and sometimes even stones and dust. During the 18th and 19th centuries in the United States, milk was often watered down and coloured with chalk or plaster, which were also used to bulk up flour. Lead was added to wine and beer, and coffee, tea and spices were mixed with dirt, sand or other leaves. In London in the 19th Century, preserved fruit and vegetables were artificially coloured with copper salts to improve their appearance and apparent value for consumers.1
In recent times, there have been cases of road salt being sold as food salt, farmed fish being promoted as freshly caught and of course the much‐publicised scandal of horsemeat being sold as beef.2 More seriously, the addition of melamine to milk and infant milk powder to falsely boost its apparent protein content in China in 2008 resulted in the death of six infants, hospitalization of 54,000 babies and an estimated 300,000 children affected in total.3
Apart from food safety, fraudulent activities also impact on food and beverage brand confidence, company reputation and the market economy. Detecting and preventing food and beverage fraud requires a reliable, cost-effective analytical process, based on effective analytical technologies that are able to provide the required sensitivity, selectivity and accuracy.
Applying Isotope Ratio Mass Spectrometry (IRMS) to Food and Beverage Fraud Identification
One particularly effective approach for food and beverage fraud testing is to use stable isotope measurements, because stable isotopes can differentiate between food and beverage samples which otherwise share identical chemical compositions. The ratios of certain isotopes, notably those of hydrogen, carbon, nitrogen, oxygen and sulphur, in food samples provide a fingerprint which can be used to identify with certainty where a particular food originates from and/or whether the food has been adulterated with cheaper ingredients.
Applications where stable isotope ratio analysis, using an elemental analysis system coupled with isotope ratio mass spectrometry (EA-IRMS) has been successfully applied to food authenticity testing include detecting adulteration of honey, proving the provenance of wine and differentiating organic and non-organic grown vegetables .
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As well as EA-IRMS, GC-IRMS, using a suitable interface between the GC and IRMS instruments, is a highly effective technique for some origin and authenticity applications. In an interesting application developed by my colleague, Dr. Dieter Juchelka, at the Thermo Fisher Scientific Mass Spectrometry Center of Excellence in Bremen, Germany, GC-IRMS was applied to proving the geographical origin of tequila.
Agave tequilana is a native plant of the Jalisco region in Mexico and forms an important economic product due to its use as a base ingredient in tequila. The agave tequilana plant is used because of its high sugar (mainly fructose) content. It is photosynthetically part of the C4 plant group, which means that it has a unique carbon isotope fingerprint of -8‰ to -14‰. During the growth of all plants, biosynthesis of organic molecules by the plant uses water that comes mainly from rainfall. Tequila is produced exclusively in 5 areas of Mexico: Jalisco, Nayarit, Michoacan, Guanajuato and Tamaulipas, and the oxygen (and hydrogen) isotope fingerprints of the agave tequilana plant is primarily generated by the relative proportion of these isotopes in the rainwater in those regions. The composition of these isotopes therefore provides a geographical tool for ascertaining the origin of the tequila. The figure below shows an example of carbon and oxygen isotope measurements on various tequila samples, measured using the Thermo Scientific™ GC IsoLink™ II Interface for GC-IRMS.
The above figure clearly isolates genuine tequila from lower grade commercial tequila as well as identifying samples which have been blended with sugar cane extracts.
As this article has shown, isotope ratio mass spectrometry combined with either an elemental analyser (such as the Flash™ Series) or gas chromatography provides a powerful solution for detecting and combating food and beverage fraud. If you’d like to learn more about what these technologies can do for your food testing needs, take a look at our Food Authenticity and Labeling web pages and to browse application notes, scientific posters and webinars visit our dedicated food integrity webpage.
Thermo Scientific offers a wide range of other analytical solutions to help you achieve your food safety, authenticity and QA/QC objectives. If you have any questions about methods, workflows or products for these application areas, from trace elemental analysis and chromatography to organic elemental analysis and high resolution mass spectrometry, just let us know via the comments box below.