Thymol-Loaded Polymeric Nanoparticles Improve the Postharvest Microbiological Safety of Blueberries.

RESEARCH BACKGROUND

The presence of on raw food products raises the concern of yersiniosis as most of the berries are consumed raw. This is a challenging issue from the food safety aspect since it could increase the occurrence of foodborne diseases among humans. Thus, it is crucial to implement an effective sanitation before the packaging.

EXPERIMENTAL APPROACH

This study aims to synthesize and characterize thymol-loaded polyvinyl alcohol (Thy/PVA) nanoparticles as a sanitizer for postharvest treatment of blueberries. Thy/PVA nanoparticles were characterized by spectroscopic and microscopic approaches, prior to the analyses of antimicrobial properties.

RESULTS AND CONCLUSIONS

The diameter size of the nanoparticles was on average 84.7 nm, with a surface charge of -11.73 mV. Based on Fourier transform infrared (FTIR) measurement, the Thy/PVA nanoparticles notably shifted to the frequency of 3275.70, 2869.66, 1651.02 and 1090.52 cm. A rapid burst was observed in the first hour of release study, and 74.9 % thymol was released from the PVA nanoparticles. The largest inhibition zone was displayed by methicillin-resistant (MRSA), followed by and . However, amongst these bacteria, the inhibition and killing of required a lower concentration of Thy/PVA nanoparticles. The treatment successfully reduced the bacterial load of on blueberries by 100 %.

NOVELTY AND SCIENTIFIC CONTRIBUTION

Thymol is a plant-based chemical without reported adverse effects to humans. In this study, by using the nanotechnology method of encapsulation with PVA, we improved the stability and physicochemical properties of thymol. This nanoparticle-based sanitizer could potentially promote the postharvest microbiological safety of raw berries, which may become an alternative practice of food safety.