According to the WHO, about 1 in 10 people get sick after consuming contaminated food, with close to 420,000 dying. Meanwhile, food companies lose billions of dollars yearly because of food spoilage.
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In this article, we provide a background to what food spoilage is, the consequences it has on the food industry, and how sensors can be used to monitor food spoilage. We also discuss some commercially available sensor technologies and the prospects of sensor use in monitoring food spoilage.
Food Spoilage: What it is and How it Occurs
Food spoilage is a term used to refer to food that has become inedible because it can cause undesirable effects on its consumer.
Food spoilage occurs when microorganisms originally in food or through contamination grow beyond a minimal level consuming nutrients from it to form other undesirable by-products. These by-products change the appearance, texture, taste, and smell of food, making it unfit for consumption. This is often referred to as microbiological food spoilage.
In some cases, the microorganisms can also be pathogenic and cause lethal diseases. Bacteria, yeasts, molds, parasites, and higher animals can be the cause of food spoilage.
Chemical food spoilage can also occur whereby chemical entities in the food react on their own with each other forming new compounds that are undesirable and can alter the food's characteristics. Compounds that can cause spoilage include toxins, heavy metals, organic compounds, and more.
Consequences of Food Spoilage on the Food Industry
Food spoilage and related incidents cause problems at various levels in the food industry. When food spoilage occurs, consumer confidence is affected, and the food industry incurs several losses as a result. For example, the impact of food recall on the food industry is often severe. It can lead to severe financial losses of several billions of dollars yearly. In addition, it affects the industry's social corporate responsibility image, which can affect in the long run investments and share price of companies, ultimately leading to business failure and bankruptcy.
How Can Sensor Technologies be Used to Prevent/Monitor Food Spoilage?
To deal with losses from food spoilage, food companies employ many approaches.
Expiration dates are widely used as a food quality metric to estimate the time for which food retains an acceptable quality. To go further, companies resort to using technologies that monitor food quality as it moves along the value and distribution chain. One of these is sensor technologies that are already being successfully used. Some of these technologies are advanced in that they report the quality of food in real-time.
Sensor technologies can be used to monitor food spoilage by tracking changes in quality indicators like temperature, pH change, humidity, gases produced, and the growth of microorganisms.
Researchers are actively looking into food packaging as a platform to incorporate sensors for monitoring food quality. Food packages traditionally preserve the food content from the external environment by acting as a barrier that prevents contaminants, oxygen, or moisture from reaching it.
The idea is to develop packaging systems with sensors that interact with both the food and the environment to provide information that can be used to improve the product's shelf life. This is achieved by using specifically designed materials like polymers that react to these changes and display a detectable outcome.
Examples of Sensors Used to Monitor Food Spoilage and Industry Examples
Different types of sensors are being developed that exploit different quality indicators to provide informative data about the state of food. For example, two sensors that have been developed and are now commercially available are based on time-temperature and oxygen detection.
The time-temperature detection target utilizes a redox reaction to oxygen defusion sensing mechanism that reports through a color change using a paper or plastic substrate. This is the case of the Tempix indicator, which retains its black bands when a product has been handled within the recommended temperatures during its movement to the consumer.
Another example is Timestrip plus, which is reported to be a low-cost and high-tech option that can monitor temperature breaches.
There is also the Mitsubishi ageless eye oxygen indicator that reports the presence of oxygen as an in-package monitor.
Other detection systems like tracing devices are increasingly conjugated with hand-held smartphones due to their high computational power and wide availability. Their high functionality can be used for high-resolution imaging helpful for pathogen testing or even to detect allergens.
RFID technology uses sensors and an automated identification system with little or no human intervention.
They are considered cost-effective options because they can modify food packages with simple devices like inkjets. This is the case of a passive vapor sensor developed by the Yan group at the University of Toronto, which is based on carbon black known to swell in the presence of some volatile compounds.
Future of Sensors in Preventing Food Spoilage
Sensor technologies are proving to be relevant to improving the quality, safety, and shelf-life of food products. Researchers are developing several sensing techniques that detect different indicators of food quality.
Only a few of these are available commercially because manufacturing costs are high. Improvements in technology and materials used in sensing probes will, in the long run, improve the cost-effectiveness of the process. Sensors will ultimately provide advanced assurance of quality and maximize the shelf life of food making the food industry more sustainable.
Artificial Intelligence technologies are also researched intensively to provide real-time and easy-to-use systems that can provide rapid information about food quality. In some cases, controlling the environment to avoid food spoilage and increase the shelf life of food.
References and Further Reading
Gunawan, I., Vanany, I., and Widodo, E. (2022). Bulk food recall decisions: Postponement and preponement to sustain food business. Journal of Food Engineering, 317, 110843. https://doi.org/10.1016/j.jfoodeng.2021.110843
Sonwani, E., Bansal, U., Alroobaea, R., Baqasah, A. M., and Hedabou, M. (2022). An artificial intelligence approach toward food spoilage detection and analysis. Frontiers in Public Health, 9. https://www.frontiersin.org/article/10.3389/fpubh.2021.816226
Yousefi, H., Su, H.-M., Imani, S. M., Alkhaldi, K., M. Filipe, C. D., and Didar, T. F. (2019). Intelligent food packaging: A review of smart sensing technologies for monitoring food quality. ACS Sensors, 4(4), 808–821. https://doi.org/10.1021/acssensors.9b00440