Food toxins are regarded as a major source of health risks, serious illnesses susceptible to even death. These dangerous pathogens may lead to significant economic impact worldwide. The food production chain undergoes different stages like harvesting, processing, storage, packaging, distribution, and lastly preparation, and consumption. Therefore, each step is susceptible to risks of environmental contamination. Nowadays, the carbon quantum dots (CDs) are regarded as one of the most widely used hybrid carbon nanomaterials due to their different magical physical and chemical properties. The CDs have a size below 10 nm and show the fluorescent property. The CDs find vast applications in different fields like sensing, food safety, drug delivery, bioimaging, catalyst, energy conversion, etc. Compared to other available methods, the fluorescence detection techniques have low cost, easy handling, and safe operating system. There is a need for a review to compile the fluorescence properties of carbon nanodots used to detect food pathogens. This brief review is addressed in that direction and mostly focused on the synthesis of carbon dots-based fluorescence sensors for detecting pathogens and toxins in foods and beverages. The detailed mechanisms and origin of fluorescence properties of carbon quantum dots are also highlighted herewith.

    Abstract
    1 Introduction
    2 Synthesis of carbon dots
        2.1 Top–down process
        2.2 Bottom–up approach
    3 Characterization of carbon dots
    4 Origin of fluorescence properties of CDs
        4.1 The quantum confinement effect or size effect or the core emission
        4.2 The surface states
        4.3 The molecular state
    5 Mechanism of fluorescence sensing using CDs
        5.1 Photo-induced electron transfer (PET)
        5.2 Resonance energy transfer (RET)
        5.3 Photo-induced charge transfer (PCT)
        5.4 Inner filter effect (IFE)
    6 Design of CDs-based fluorescence sensors for food toxin
    7 Food quality assessment through fluorescent CDs
    8 Summary and future perspectives
    Acknowledgements 
    References

• Manash Jyoti Deka(Department of Chemistry, Bimala Prasad Chaliha College)
• Devasish Chowdhury(Material Nanochemistry Laboratory, Physical Sciences Division, Institute of Advanced Study in Science and Technology)
• Bhabesh Kumar Nath(Department of Physics, Birjhora Mahavidyalaya, Birjhora)