Detecting Food Adulteration with Benchtop NMR

Food authenticity is not a new concept, but it remains a ubiquitous issue across the globe. While it is difficult to quantify how prevalent food fraud is throughout the entire supply chain, experts estimate its impact on the food industry to be in excess of $50 billion each year. Incidences of food fraud over the past decade have increased media attention on the issue of food authenticity, which has, subsequently, made it a hot topic in the food industry and regulatory agencies.

Over the last few years, nuclear magnetic resonance (NMR) technology has become an increasingly accessible technique for food safety laboratories, particularly for verifying food and beverage authenticity. NMR analysis can rapidly create a molecular “fingerprint” of a product, identify any adulterants, and establish the true country of origin—a frequent target for fraud.

The Demand for Accurate and Rapid Quality Control in Food Safety Labs

Traditionally, the food safety industry has utilized gas chromatography (GC) and polymerase chain reaction (PCR) testing to determine the chemical composition of products. However, these methods require large quantities of expensive reagents to operate effectively and can take hours, even days, to produce results.

Since its discovery in 1946, NMR spectroscopy has continued to grow as an indispensable analytical tool across a range of applications. NMR is an information rich, non-destructive analytical technique that provides detailed information about molecular structure and dynamic processes. It is also a primary quantitative method that can determine the concentration of molecules, even in complex mixtures.

NMR is utilized in the food industry for a variety of applications, including the determination of the chemical composition of foods and the quantitative analysis of changes induced by processing, storage, and spoilage. NMR has become a particularly popular technique in the food safety sector over the last decade, primarily used for verifying the authenticity of food and beverages and detecting counterfeit products.

In NMR analysis, food or beverage samples are analyzed and compared to large databases of genuine products, generating a “fingerprint” that users can compare with the test sample in order to check for compliance. Information that can be gathered not only includes what components the sample contains, but also details such as geographical origin to confirm if the product is from the source claimed.

The Shift Toward Benchtop NMR

The past 50 years of NMR spectroscopy innovation have, until recently, centered around steadily increasing the magnetic field strength of instruments. Now, new benchtop NMR spectrometers offer the reproducibility and stability of NMR technology in a more accessible, smaller instrument that can be installed on the lab bench.

A benchtop NMR spectrometer is significantly more compact and portable than the conventional NMR instrument. It does not require dedicated infrastructure or an extensive installation process. Benchtop spectrometers offer improved workflow, even for novice users, as they are intuitive in use and do not require extensive user training.

Low-field benchtop NMR can provide a high value solution for the food sector by delivering the same answer as high-field NMR to an array of analytical questions. The advantages of benchtop NMR systems are paving the way for the introduction of this technology:

• No specialist NMR expertise required;
• Same direct quantification and deep structural information as high-field NMR;
• Compact benchtop size;
• No additional infrastructure needed;
• Cryogen-free permanent magnets—no need to refill liquid helium;
• Operates from a single standard power socket; and
• Easy maintenance and minimal cost of ownership.

The significantly reduced costs, low maintenance requirements, and simplicity of benchtop NMR spectrometers are leading this technology. Their advanced electronics and methodology make them ideally suited to high-throughput quality control.

Supporting Food Quality and Authenticity

Olive oil is one of the top-10 most adulterated food products, so detecting its dilution with a lower quality substitute, such as sunflower oil, is critical to the industry. The edible oil industry is a prime target for adulteration, with high quality oil, such as olive oil, often adulterated with significant levels of other edible oils that have a lower market price or are of a lower quality, such as hazelnut oil, sunflower oil, soybean oil, rapeseed oil, or corn oil. The olive oil industry has been petitioning FDA for years for a standard.