Assessment of the quality of food is crucial to ensure the safety of consumers and prevent food-borne illness. Therefore, stringent laws and regulations are exercised on the preparation, packaging and transportation of almost all food products. Conventional methods for the assessment of food contamination, of which include culturing of microbial growth, chromatographic techniques and immunoassays are often time consuming and tedious processes. To address these limitations, the advent of biosensors has emerged as a revolutionary way to evaluate the quality of food products.
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As a result of their specificity, portability and quick response, biosensors have been widely used for a variety of applications in the food industry. In particular, optical biosensors exhibit a unique potential for the detection of pathogens, pesticides, drug residues and other toxic elements, such as heavy metals, that may be present within various food products.
Various types of transducers that work based on electrochemical, piezoelectric, thermometric and optical techniques are used in biosensors. Biosensors are devices that generate a measurable response to specific elements following the binding of the analyte in the sample to the biological recognition element of the device. This response is then analyzed and transmitted as an output value that is displayed in the form of either qualitative or quantitative units of the amount of analyte present.
During the biosensor’s analysis of a food sample, any contaminants will be detected by immobilization of the bioreceptor molecules present in the sample onto the bio-recognition layer of the sensor that is in close proximity to the transducer. Biosensors therefore exhibit a unique versatility in their ability to rapidly analyze multiple food samples once the reusable probe is properly cleaned.
Optical biosensors utilize optical fibers, surface plasmon resonance, planar wave guides and microarrays to detect specific analytes by measuring changes in the amplitude, frequency, phase and polarization of light within the sample. These types of biosensors are particularly useful due to minimal sample treatment requirements and their unique ability to detect contaminants or pathogens present in complex matrices. Due to the sensitivity, detection limit and their capacity to detect analytes in a variety of samples, optical biosensors are often used for a variety of quality control purposes within the food industry.
Applications of Optical Biosensors in Quality and Safety Assessment of Food Products
Detection of Pathogens
Microbial contamination of food products can cause infectious diseases to arise in both humans and animals. Optical biosensors provided an effective alternative to the traditional, and often tedious and time-consuming, quality assessment techniques. In particular, luminescence-based optical detection techniques that measure enzyme-mediated reactions carried out by the microorganisms in the food samples have proven to be both rapid and incredibly useful in ensuring food safety.
Detection of Pesticide Residues
Due to the widespread use of pesticides in agriculture, it is unfortunately not uncommon for agricultural food products to be contaminated with traces of pesticides. Both acute and chronic exposure to pesticide residues can arise as a result of the passive consumption of these molecules within our food products. Biosensors are a therefore a quick and efficient way to detect the levels of unwanted pesticide in food products.
Detection of Drug Residues
Animals, such as cows, pigs and chickens, raised for food can be treated with various veterinary medicines during their lifetime for a wide range of reasons. In an effort to prevent the unwanted ingestion of these medications, optical biosensors can be used to detect the presence of these compounds in meat and dairy products, which could potentially cause illnesses when ingested by humans.
Detection of Other Toxic Elements
Elements such as adulterants, heavy metals and other toxic compounds that may be present in food products can also be detected by optical biosensors.
Humans have adopted various ways to preserve and store food products in an effort to increase their shelf life. These methods have allowed for the efficient transportation of food products across the globe, which has largely benefited the health and economy in various nations. The potential contamination of food products by the chemicals used to extend their storage life, as well as by various other pathogens and elements prior to, during and following their transportation remains a huge concern. The development of quick and efficient methods to quantify the levels of these contaminants and assess the quality of food products therefore remains imperative to ensuring food safety for the global population. The specificity, speed and ease of use associated with optical biosensors has already provided significant improvements in food safety and quality control.
- Narsaiah, K., Jha, S. N., Bhardwaj, R., Sharma, R., & Kumar, R. (2012). Optical biosensors for food quality and safety assurance – a review. Journal of Food Science Technology 49(4); 383-406. DOI: 10.1007/s13197-011-0437-6.