Investigating sustainable and renewable sources of carbon quantum dots for utilization in food packaging systems: A review

Carbon quantum dots (CQDs) have appeared as fascinating nanoscale additives obtained from green sources, including plants, food, animal, human, and microbial waste. The distinctive physicochemical properties of CQDs—possessing stable fluorescence, excellent water solubility, and high biological efficacy—render them appropriate for use within the food sector. Therefore, this paper examines the potential of CQDs as nanofillers in biopolymer-based packaging films, highlighting their contributions to mechanical strength, optical clarity, thermal stability, barrier performance, and environmental sustainability. The research explores environmentally sustainable synthesis methods and uses of CQDs in the food industry, such as smart packaging, spoilage detection, and food analysis. Incorporation of CQDs into biopolymer films greatly enhances mechanical strength, optical transparency, and thermal stability while reducing water vapor permeability. These alterations achieve improved preservation of food by inhibiting microbial growth and retarding oxidative spoilage. Furthermore, their fluorescence-based sensing function allows detection of a broad range of contaminants, such as antibiotics (e.g., kanamycin, tetracycline), heavy metals, pesticides, toxins, and food spoilage indicators. Given their multifunctional properties, the application of CQDs is recommended in the development of food packaging systems, such as active films for perishable items, intelligent labels, and coatings with improved barrier characteristics for shelf life extension and quality improvement.