New Raman Spectroscopy Techniques Promise Safer Produce

Fruits and vegetables are two important staples in human nutrition. These two food groups contain essential nutrients, such as potassium, fiber, zinc, and vitamins C, E, and A, among others (1). As a result, these two food groups could have a noticeable impact on human health. For adults who regularly consume five servings of fruits and vegetables per day compared to adults who only have two servings of fruits and vegetables per day, they experience a 13% lower risk of any-cause mortality, a 10% decrease in risk of contracting cancer, and a 35% lower risk of cardiovascular disease (1).

Top view of colorful vegetables and fruits arranged in a rainbow color gradient. Generated with AI. | Image Credit: © mister - stock.adobe.com

Fruits and vegetables are also thought to provide mental health benefits. Numerous studies have been conducted that shows how consuming fruits and vegetables have tangible benefits to the mental well-being of humans (2,3). For example, a study observed that fruit and vegetable consumption had an inverse correlation with anxiety and depression symptoms, where the more of these types of foods consumed led to reduced likelihood of the individual exhibiting symptoms associated with anxiety and depression (2).

Armed with this knowledge, consumers therefore seek to incorporate fruit and vegetables into their diet, which increases demand for these food products. The problem, though, is that these foods are often at risk of contamination from organic pollutants throughout their growth and distribution phases (4). Therefore, analytical methods are required to help manufacturers identify pesticide restudies, toxin contamination, and harmful microorganisms in these foods before they go to market.

A recent review published in Food Chemistry explores this issue. Zhiming Guo of Jiangsu University and his team examined the role of surface-enhanced Raman spectroscopy (SERS) in enhancing the safety of fruits and vegetables in food safety, highlighting both the current capabilities and future potential of this method in ensuring the health of consumers (4).

SERS is a powerful analytical technique that enhances Raman scattering, allowing for the detection of molecules at very low concentrations. According to the review, the two main detection modes employed by SERS in food safety are direct (label-free) detection and indirect (labeled) detection (4). In direct detection, the SERS substrate enhances the signal of the target molecule itself, making it possible to obtain both qualitative and quantitative results through the molecule's Raman fingerprint (4). In indirect detection, molecules are tagged with labels that make their presence more easily detectable (4).

SERS technology has already proven how useful it can be. Its ability to detect a wide array of contaminants makes SERS a good technique to use in food analysis (4). It also can detect harmful chemicals at low levels, a benefit other analytical methods do not provide (4).

In addition to pesticides, SERS has also proven effective in identifying harmful microbial infections and microbial toxins in fruits and vegetables. This is particularly relevant in preventing outbreaks of foodborne illnesses caused by bacteria like E. coli and salmonella, which can thrive on produce if not properly detected and managed (4). SERS technology offers a quicker, more sensitive alternative to traditional detection methods, which are often time-consuming and labor-intensive (4).

Guo’s article also discusses current challenges with SERS technology that need to be addressed moving forward. For example, a major limitation is that SERS substrates are not reproducible. Because these substrates play a critical role in amplifying the signal of the target molecule, inconsistencies in their performance can lead to unreliable results (4). For SERS to become more practical for large-scale use, researchers must focus on improving the design and manufacturing of these substrates (4).

Another major challenge in SERS technology is that it is falling behind other analytical techniques when it comes to portability. For example, Raman spectrometers have emerged as a popular technique of choice when on-site analysis must be conducted because it does not require sample preparation beforehand (5). If portable SERS analyzers were to be developed, they could revolutionize the way food safety inspections are carried out, allowing for on-site testing of produce in supermarkets, farms, and processing facilities (4).

With these advancements, the authors assert that SERS could become an indispensable tool for not only for safeguarding human health, but for also improving the economic value of agricultural products by ensuring their safety and quality (4).

References

1. Darby, M. 7 Mental and Physical Health Benefits That Come From Eating Fruits and Vegetables. Deseret News. Available at: https://www.deseret.com/2024/2/13/24070916/mental-physical-health-benefits-fruits-vegetables/#:~:text=Fruits%20and%20veggies%20aid%20in%20digestive%20health.,both%20of%20which%20aid%20in%20healthy%20digestion (accessed 2024-10-18).
2. Ainamani, H. E.; Bamwerinde, W. M.; Rukundo, G. Z.; et al. Fruit and Vegetable Intake and Mental Health Among Family Caregivers of People with Dementia in Uganda. Ment. Health Prev. 2021, 24. DOI: 10.1016/j.mhp.2021.200223
3. Glabska, D.; Guzek, D.; Groele, B.; Gutkowska, K.; et al. Fruit and Vegetable Intake and Mental Health in Adults: A Systematic Review. Nutrients 2020, 12 (1), 115. DOI: 10.3390/nu12010115
4. Guo, Z.; Wu, X.; Jayan, H.; et al. Recent Developments and Applications of Surface Enhanced Raman Scattering Spectroscopy in Safety Detection of Fruits and Vegetables. Food Chem. 2024, 434, 137469. DOI: 10.1016/j.foodchem.2023.137469
5. George, N.; Singh, H.; Jotaniya, R.; Pandya, S. R. Raman Spectroscopy for the Determination of Forensically Important Bio-fluids. Forensic Sci. Int. 2022, 340, 111441. DOI: 10.1016/j.forsciint.2022.111441