Food safety is a growing global priority. From pathogens to heavy metals, the list of potential food contaminants continues to expand—and so does the demand for fast, accurate ways to detect them.
Traditional lab tests are reliable, but they can be slow, expensive, and destructive to samples. That’s where lasers come in. These technologies use light to analyze food at the molecular level—quickly, non-invasively, and with increasing precision.
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Some technologies, like laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy, are already being used for rapid onsite screening with handheld devices. Others, like near-infrared spectroscopy, enable non-destructive freshness testing and fraud detection across supply chains.
From identifying trace metals in infant formula to detecting pesticide residues in fruit juice, laser-based spectroscopy is reshaping how we monitor food safety.
In this article, we explore how laser-induced techniques like LIBS, Raman, and NIR spectroscopy work, where they're being applied, and what’s holding them back from wider adoption.
Principles of Laser-Based Contaminant Detection
Laser-based detection works by shining light onto food and analyzing how that light interacts with different components. This reveals chemical or biological signs of contamination. There are three main types of laser-based spectroscopy commonly used in food safety:
Laser-Induced Breakdown Spectroscopy
LIBS uses short, high-energy laser pulses to create a tiny plasma on the surface of a sample. As the plasma cools, it gives off light that shows the elemental makeup of the material. By looking at the light’s spectrum, scientists can detect contaminants like heavy metals or signs of bacterial presence.
For example, LIBS can spot trace amounts of lead or cadmium in infant formula by picking up their unique spectral fingerprints. It requires very little sample prep and gives results in just a few seconds, making it ideal for industrial testing and quality control.1-3
Raman Spectroscopy and SERS
Raman spectroscopy works by measuring how laser light scatters when it hits molecules. This scattering reveals how the molecules vibrate, which can help identify them. While normal Raman signals are often weak, a variation called surface-enhanced Raman spectroscopy (SERS) boosts them using tiny structures made of gold or silver.
SERS makes it possible to detect very small amounts of things like pesticides or bacteria, down to parts-per-billion (ppb).4,5
For instance, a study in Food Chemistry used SERS to find the fungicide thiabendazole in fruit juice at levels as low as 0.032 parts-per-million (ppm), showing it can be used for real-time safety checks.6
Near-Infrared (NIR) Spectroscopy
NIR spectroscopy analyzes the vibrations of molecules such as water, fats, and proteins by measuring their overtone and combination vibrations.
Portable NIR devices can be used to check fruit freshness by spotting signs of spoilage, or to detect if products like honey have been mixed with cheaper ingredients. These devices match the sample’s unique spectral fingerprint against a reference database to find any irregularities.
This non-destructive method helps maintain food quality, allowing consumers to enjoy unadulterated products while also reducing waste and extending shelf life.7
Spectroscopy - how to see the quality in food
How Is This Technology Actually Being Used in Food Safety?
Pathogen Detection
Pathogens like Salmonella and E. coli pose severe health risks. LIBS differentiates live vs. heat-killed bacteria on food surfaces by analyzing elemental composition shifts, achieving results in minutes without culturing.
Raman spectroscopy, combined with machine learning, can also identify different bacterial species in milk by analyzing their unique lipid and protein signals.2,5
Adulterant Identification
Food fraud, such as adding melamine to milk or substituting olive oil with cheaper alternatives, is a growing issue. That’s where laser-based techniques can help.
LIBS rapidly identifies adulterants like whey in milk powder by detecting discrepancies in calcium and potassium levels. Raman spectroscopy excels in spotting synthetic dyes or unauthorized additives, such as Sudan dyes in spices.1,5
Heavy Metal Contamination
Toxic metals like arsenic and mercury can build up in crops through polluted soil or water. LIBS can measure these elements in foods like rice and seafood with minimal sample prep.
Meanwhile, SERS enables ultra-sensitive mercury detection by using chemical probes that amplify the Raman signal when they bind to the metal.3,5
Spoilage and Freshness Monitoring
NIR tools are helping producers evaluate freshness in meat by tracking pH and microbial changes. For fruits, laser-based imaging methods are being used to assess ripeness and spot internal defects, without cutting them open.7,8
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So, What’s Stalling the Rollout of Lasers in Food Testing?
Laser-based tools are opening up exciting possibilities in food safety, but a few key challenges still limit how widely they’re used.
One issue is sensitivity. Detecting contaminants at extremely low levels—like aflatoxins in the parts-per-trillion range—remains difficult, although techniques like SERS are steadily improving.3,5
Complex food types, such as blended or processed products, also produce overlapping spectral signals that can be tricky to interpret without advanced data tools.
There’s also the matter of cost and accessibility. High-end laser systems can be expensive, and there’s currently a lack of universal standards for how they should be used across the industry. That creates a barrier, especially for smaller producers.3,7,9
Despite these hurdles, progress is happening fast. Advances in artificial intelligence (AI) and sensor miniaturization are making laser systems more powerful and portable. Hybrid approaches—like combining LIBS and Raman—could offer a fuller picture by detecting both elemental and molecular contaminants at once. AI is also helping make sense of messy spectral data, improving accuracy in real-world conditions.5,8,9
Some governments and regulatory agencies are already exploring these tools for inspections. The EU, for example, has introduced laser-etched labels on fruit to help track provenance and quality.
To go mainstream, laser-based systems will need clearer standards, lower costs, and more validation across different food types. But if those pieces fall into place, lasers could soon become a frontline tool in global food safety, spotting contaminants quickly, cleanly, and with unprecedented precision.
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References and Further Reading
- Markiewicz-Keszycka, M. et al. (2017). Laser-induced breakdown spectroscopy (LIBS) for food analysis: A review. Trends in Food Science & Technology, 65, 80-93. DOI:10.1016/j.tifs.2017.05.005. https://www.sciencedirect.com/science/article/abs/pii/S0924224417300377
- Rai, D. et al. (2025). Libs–a promising technique for control of food quality. Journal of Optics. DOI:10.1007/s12596-024-02436-2. https://link.springer.com/article/10.1007/s12596-024-02436-2
- Acevedo, A. (2023). Using LIBS to Analyze Food. Spectroscopy Online. https://www.spectroscopyonline.com/view/using-libs-to-analyze-food
- Petersen, M., Yu, Z., & Lu, X. (2021). Application of Raman Spectroscopic Methods in Food Safety: A Review. Biosensors, 11(6), 187. DOI:10.3390/bios11060187. https://www.mdpi.com/2079-6374/11/6/187
- Xiao, L., Feng, S., & Lu, X. (2023). Raman spectroscopy: Principles and recent applications in food safety. Advances in Food and Nutrition Research, 106, 1-29. DOI:10.1016/bs.afnr.2023.03.007. https://www.sciencedirect.com/science/article/abs/pii/S1043452623000220
- Chen, Z. et al. (2022). Facile synthesis of Au@Ag core–shell nanorod with bimetallic synergistic effect for SERS detection of thiabendazole in fruit juice. Food Chemistry, 370, 131276. DOI:10.1016/j.foodchem.2021.131276. https://www.sciencedirect.com/science/article/pii/S0308814621022822
- Fodor, M. et al. (2023). The Role of Near-Infrared Spectroscopy in Food Quality Assurance: A Review of the Past Two Decades. Foods, 13(21), 3501. DOI:10.3390/foods13213501. https://www.mdpi.com/2304-8158/13/21/3501
- Teng, X., Zhang, M., & Mujumdar, A. S. (2021). Potential application of laser technology in food processing. Trends in Food Science & Technology, 118, 711-722. DOI:10.1016/j.tifs.2021.10.031. https://www.sciencedirect.com/science/article/abs/pii/S0924224421005987
- Lasers For Precision Agriculture & Food Safety. Power Technology, Inc. https://www.powertechnology.com/industry/agriculture-timber-food-inspection-safety-lasers/
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