Colorimetric Paper Sensor for Food Spoilage Based on Biogenic Amine Monitoring

Biogenic amines (BAs), nitrogenous molecules usually present in different foods, can be considered an indicator of freshness and food quality since their amount increases during food spoilage. Their detection, possibly in real time via the use of smart packaging, is therefore of crucial importance to ensure food safety and to fulfill consumers' demand. To this end, colorimetric sensors are considered one of the most feasible solutions. Here, we report a user-friendly colorimetric sensing paper able to detect BAs via the naked eye. The sensing molecule is the aglycone genipin, a natural cross-linking agent extracted from gardenia fruit, able to bind BAs producing water-soluble blue pigments. The paper sensor was applied to chicken meat quality monitoring and a quantitative analysis was performed with image acquisition via a smartphone camera, achieving a limit of detection equivalent to 0.1 mM of putrescine. The suitability of the BA sensing paper was assessed by integrating the sensor into smart packaging and analyzing commercial chicken meat samples stored at different temperatures; the results of the sensor paralleled the best before date indicated on the label, confirming the potential applicability of the sensor as a smart label.

Automated summary

Biogenic amines (BAs), nitrogenous molecules present in various foods, can indicate freshness and food quality as their levels increase during spoilage. Detecting BAs in real time using smart packaging is crucial for ensuring food safety and meeting consumer demands. This study developed a user-friendly colorimetric sensing paper that can visually detect BAs. The paper sensor, using the natural cross-linking agent genipin, was able to produce water-soluble blue pigments when binding with BAs. The sensor was successfully applied to monitoring chicken meat quality and achieved a limit of detection equivalent to 0.1 mM of putrescine through quantitative analysis using a smartphone camera. The sensor's suitability was verified by integrating it into smart packaging and analyzing commercial chicken meat samples stored at different temperatures, with results aligning with the labeled best before date and confirming the sensor's potential as a smart label.