POLYDIACETYLENE SYSTEM DEVELOPMENT FOR COLORIMETRIC TRANSITION-BASED DETECTION OF MICROBIOLOGICAL CONTAMINATION IN FOOD EXTRACTS

Early detection of pathogenic and spoilage microorganisms is essential to ensure food safety. In this context, polydiacetylene (PDA) vesicles can be a promising approach for monitoring the microbiological quality of food products besides being used as intelligent packaging. For that, this study aimed to enable the detection of microorganisms in extracts of cheese and sausages using PDA vesicles produced from a new, cost-effective methodology(Patent BR10202300874). Therefore, sausage and cheese extracts were separately contaminated with Pseudomonas aeruginosa ATCC 15442, Escherichia coli ATCC 11229, Staphylococcus aureus ATCC 6538, Listeria monocytogenes ATCC 15313, and Salmonella enterica serovar Choleraesuis ATCC 10708 (106 CFU.mL-1). Following, 50 µl of bacterial inoculam was added into 150 µL of blue vesicles, and color transitions were observed after 15 minutes, which were increased at the end of 20 hours. In this regard, colorimetric responses (CR) were calculated by measuring the absorbance at 540 nm and 640 nm of the systems in UV-VIS spectroscopy. CR was greater than 10% (significant transition) when vesicles were in contact with sausage extracts contaminated with microorganisms. This color transition was also noticed by the naked eye, except for the bacterium S. aureus (CR = 3.4%). Although, CR values for cheese extracts were less than 10%, the color transition was visible. However, the absorbance reading was hindered due to the precipitation of components in the mixture. In this context, it was observed that the complexity of food matrices influenced the color transition by vesicles. Therefore, controlled conditions shall be optimized to enable PDA systems to ensure the microbiological safety of different food products.