Free-standing carboxymethyl cellulose film incorporating nanoformulated pomegranate extract for meat packaging.

This study aimed to explore an innovative approach to enhancing the shelf-life and quality of meat products through the application of an active packaging system. The study involved the development of new free-standing carboxymethyl cellulose (CMC) nanocomposite films incorporated with nanoencapsulated flavonoids derived from pomegranate extract. The loaded flavonoids, known for their antioxidant and antimicrobial properties, were nanoencapsulated via a self-assembly approach in a mixture of chitosan and sodium alginate to improve their stability, solubility, and controlled release characteristics. Chemical structure, size, and morphology of the obtained nanoparticles (Pg-NPs) were studied with FTIR, zeta-sizer, and TEM. The Pg-NPs showed particle size of 232 nm, and zeta-potential of -20.7 mV. Various free-standing nanocomposite films were then developed via incorporation of Pg-NPs into CMC-casted films. FTIR, SEM, thermal and mechanical properties, and surface wettability were intensively studied for the nanocomposite films. Barrier properties against water vapor were investigated at 2022 g·m-2d-1. The nanocomposite films possessed superior properties for inhibiting bacterial growth and extending the shelf-life of beef and poultry meat for 12 days compared with the Pg-NPs-free CMC films. This study presented a promising approach for development of active packaging systems with improved antimicrobial and antioxidant properties, and economic and environmental impacts.

Voltammetric determination of Salmonella typhimurium in minced beef meat using a chip-based imprinted sensor.

Early detection of pathogens is necessary for food quality monitoring, and increasing the survival rate of individuals. Conventional microbiological methods used to identify microorganisms, starting from bacterial culture and ending with advanced PCR gene identification, are time-consuming, laborious and expensive. Thus, in this study, a bacterial imprinted polymer (BIP)-based biosensor was designed and fabricated for rapid and selective detection of Salmonella typhimurium. Bio-recognition sites were made by creating template-shaped cavities in the electro-polymerized polydopamine matrices on a gold screen-printed electrode. The overall changes of the sensor, during the imprinting process, have been investigated with cyclic voltammetry, atomic force microscopy and scanning electron microscopy. The assay optimization and validation were accomplished, hence the highest sensitivity and selectivity towards S. typhimurium were achieved. As a result, a very low limit of detection of 47 CFU ml-1, and a limit of quantification of 142 CFU ml-1 were achieved using the newly-developed biosensor. No interference signals were detected when the S. typhimurium was tested in a mixed culture with other non-targeted pathogens such as Staphylococcus aureus, Listeria monocytogenes and Campylobacter jejuni. Eventually, the biosensor was applied to minced beef meat samples offering not only fast detection but also direct determination with no bacterial enrichment steps.

User-friendly lab-on-paper optical sensor for the rapid detection of bacterial spoilage in packaged meat products.

A lab-on-paper colorimetric sensor for detection and quantification of bacterial meat spoilage is reported. Bromocresol purple (BCP) and bromothymol blue (BTB) were used for the construction of the proposed sensor. An Android application allowing fast detection and accurate quantification of bacteria in the spoiled chicken meat samples was developed. The sensor was applied to the determination of spoilage in real chicken-meat samples, at chiller and room temperatures, and can be used for producing smart meat-packaging films. Linearity ranges were found to be 11.2 × 103 to 1.12 × 106 and 38.0 × 103 to 1.12 × 106 CFU g-1 for BTB and BCP, respectively. The calibration plots showed correlation coefficients (r) of 0.9998 (slope: 2.48 g CFU-1) and 0.9999 (slope: 1.95 g CFU-1) in case of bromothymol blue and bromocresol purple, respectively. The Android application uses standard images to plot a calibration curve for calculating the microbial count in the samples and relates it to the standard limits. Thereafter, the application shows a message with the product's freshness degree ranging from excellent to poor.