Food And Beverage Fraud Prevention Using Stable Isotope Fingerprints

Thursday, November 16th, 2017

In this article, we provide two examples of the use of isotope fingerprints in food and beverage fraud detection and provide an overview of the interpretation of these isotope fingerprints and the technology used. By Christopher Brodie, Oliver Kracht, Dieter Juchelka, Jens Radke and Andreas Hilkert, Thermo Fisher Scientific, Germany

The food and beverage industry suffers from fraudulent activities that include incorrect labelling of products and adulteration, which has a significant impact on food and beverage safety, brand names and reputation, and the market economy. Preventing food and beverage fraud is a key challenge that requires a reliable, cost-effective analytical process that can detect food and beverage fraud.

Detecting food and beverage fraud can be achieved using stable isotope measurements because stable isotopes can differentiate between food and beverage samples which otherwise share identical chemical composition: this is called the isotope fingerprint. Using the isotope fingerprint of food and beverage products is a reliable and unique technique in food and beverage fraud prevention and food safety.

Isotopes In Food & Beverage Origin And Authenticity

Stable isotopes of carbon, nitrogen, sulfur, oxygen and hydrogen can be measured from food and beverage products, such as honey, cheese, olive oil, animal meat, milk powder, vegetables, wine, liquor, water and so forth, using isotope ratio mass spectrometry techniques.

These stable isotope data can subsequently be interpreted to determine the origin, correct-labelling and trace adulteration of food and beverage products, as summarised in Table 1.

Is Your Wine Watered Down?

The most common type of fraud that relates to wine is adulteration, meaning the addition of cheaper products to the original wine, such as fruit juices, water and sweeteners, which are not related to the grapes or fermentation process from which the wine was originally produced.

Adulterated wine is then labelled as the original product, generally an expensive brand, and sold on the market as if the original product. It also relates to the re-labelling of wines, by adding the label of a more expensive wine to a bottle of a different, cheaper version and selling it on the market as an original product.

In Figure 1, we show an example of wine adulteration by the addition of water detected by oxygen isotopes using a Thermo ScientificTM GasBench II interfaced with a Thermo ScientificTM DELTA VTM Isotope Ratio Mass Spectrometer. A genuine red wine sample was measured initially to provide a baseline before the sample was sequentially adulterated by adding water. The watering technique may be used to reduce alcohol content and increase profits by producing more bottles for sale and thus reduce tax and customs duty on exported products in certain countries.

Are Your Vegetables Grown Using Organic Farming?

Supermarkets and market places stock vegetables that are labelled as “organic” because they are believed to be healthier and safer than their non-organic equivalents. Vegetables grown using organic farming methods are sold on the market for higher prices, which relates to the higher costs of production and certification of the product as organic grown. This has led to mislabelled vegetables appearing for sale on the market, with those grown with synthetic fertilisers labelled as organic. The consumer question is: are my vegetables really organic grown?

Organic vegetables are grown using organic fertilisers, such as peat, sewage sludge and animal manure, and tend to have nitrogen isotope values between 10 to 20 percent. Vegetables that are not labelled organic are grown using synthetic fertilisers, such as potash and ammonia, and tend to have nitrogen isotope values of 3 to 5 percent.

This provides a framework within which to distinguish vegetables grown using organic or synthetic fertilisers thanks to an isotope discrimination due to ammonia volatilisation, denitrification, nitrification and other N transformation processes prior to plant uptake.

In Figure 2, we show an example of tomatoes that have been grown using organic and inorganic fertilisers. The nitrogen isotope fingerprint of the tomatoes, measured using an Elemental Analyser Isotope Ratio Mass Spectrometer (EA-IRMS), such as the Thermo ScientificTM EA IsoLinkTM IRMS System, show a clear difference between tomatoes grown using organic fertilisers and synthetic fertilisers.

Summary: Isotope Fingerprints In Food And Beverage Products

Food and beverage products carry a unique chemical signature that relates to the biogeochemical processes that happened during the formation process of the materials that are present in the final product. These biogeochemical processes leave a chemical fingerprint that can be routinely detected in food and beverage products by measuring the stable isotope values of the products: this is what we call the isotope fingerprint of food and beverage products.

These stable isotope values can be interpreted to provide conclusive information on the origin of a product, meaning you can identify where in the world or within a country a product has come from, and the authenticity of a product, which means understanding if a product has been changed from its raw composition to something else.

By using isotope fingerprints to detect food and beverage fraud, laboratories can:

• Trace food and beverage fraud with unique answers about origin and authenticity.

• Extend their analytical capabilities.

• Work with an integrated analytical solution, driven by a single software for automated high sample throughput.