Recently, the demand for safe and high quality foods, as well as changes in consumer preferences have led
to the development of innovative and novel approaches in food packaging technology. One such development
is the smart or intelligent food packaging technology. Intelligent packaging has enabled to monitor
and communicate information about food quality. This technology also helps to trace a product’s history
through the critical points in the food supply chain. In general, occurrence of elevated CO2 gas level is the
prime indicator of food spoilage in packed foods and also its maintenance at optimal levels is essential to
avoid spoilage in foods packed under modified-atmosphere packaging (MAP) conditions. Hence, a CO2
sensor incorporated into food package can efficiently monitor product quality until it reaches the
consumer. Although much progress has been made so far in the development of sensors monitoring CO2,
most of them are not versatile for food packaging applications and suffers from limitations such as high
equipment cost, bulkiness, and energy input requirement, including safety concerns. Therefore, the
development of efficient CO2 sensors that can intelligently monitors the gas concentration changes inside
a food package and specific to food packaging applications is essential. In the present review, progress on
the development of different types of CO2 sensors such as optical sensors, polymer opal films, polymer
hydrogels, etc., which can be readily applicable to food packaging applications, is discussed.