Protein Chips for Detection of Salmonella spp. from Enrichment Culture

Survival of beneficial microbes in liquid bioformulation and optimization of different carrier materials using RSM technique

Soil salinity in rice cultivation areas is considered a severely limiting factor that adversely affects the quantity and quality of rice production in wetlands. Recently, the alternative use of salt-tolerant plant growth-promoting rhizobacteria (PGPR) inhabiting extreme saline conditions has gained remarkable attention and had positive effects on soil and crops. Therefore, a study has been initiated to develop a liquid biofertilizer formulation from locally isolated multi-strain salt-tolerant PGPR strains such as Bacillus tequilensis and Bacillus aryabhattai, using glycerol (5 mM), trehalose (10 mM), and polyvinylpyrrolidone (PVP) at 1% as additives to prolong the shelf-life of the bacteria. After 3 months of incubation, the bacterial population in the trehalose-supplemented mixed strain was highest at 9.73×107 CFU/mL, followed by UPMRE6 and UPMRB9 at 9.40×107 CFU/mL and 8.50×107 CFU/mL respectively. The results showed that the optimal trehalose concentration successfully prolonged the shelf-life of bacteria with minimal cell loss. Validation of quadratic optimization by response surface methodology revealed that the cell density of the mixed strain was 4.278×107 log CFU/mL after 24 h. The precision ratio was 99.7% higher than the predicted value in the minimized medium formulation: 0.267 g/mL trehalose, 1% glycerol, at 120 rpm agitation using the data analysis tools of Design Expert software. The population study confirmed the better and longer survival of salt-tolerant PGPR fortified with 10 mM trehalose, which was considered the best liquid biofertilizer formulation. Moreover, the optimized trehalose-glycerol liquid formulation can be used commercially as it is cost-effective.

Applications of biosensors for bacteria and virus detection in food and water-A systematic review

Biosensors for sensitive and specific detection of foodborne and waterborne pathogens are particularly valued for their portability, usability, relatively low cost, and real-time or near real-time response. Their application is widespread in several domains, including environmental monitoring. The main limitation of currently developed biosensors is a lack of sensitivity and specificity in complex matrices. Due to increased interest in biosensor development, we conducted a systematic review, complying with the PRISMA guidelines, covering the period from January 2010 to December 2019. The review is focused on biosensor applications in the identification of foodborne and waterborne microorganisms based on research articles identified in the Pubmed, ScienceDirect, and Scopus search engines. Efforts are still in progress to overcome detection limitations and to provide a rapid detection system which will safeguard water and food quality. The use of biosensors is an essential tool with applicability in the evaluation and monitoring of the environment and food, with great impact in public health.

Lab-on-a-chip technologies for food safety, processing, and packaging applications: a review

The advent of microfluidic systems has led to significant developments in lab-on-a-chip devices integrating several functions onto a single platform. Over the years, these miniature devices have become a promising tool for faster analytical testing, displaying high precision and efficiency. Nonetheless, most microfluidic systems are not commercially available. Research is actually undergoing on the application of these devices in environmental, food, biomedical, and healthcare industries. The lab-on-a-chip industry is predicted to grow annually by 20%. Here, we review the use of lab-on-a-chip devices in the food sector. We present fabrication technologies and materials to developing lab-on-a-chip devices. We compare electrochemical, optical, colorimetric, chemiluminescence and biological methods for the detection of pathogens and microorganisms. We emphasize emulsion processing, food formulation, nutraceutical development due to their promising characteristics. Last, smart packaging technologies like radio frequency identification and indicators are highlighted because they allow better product identification and traceability.

Fluorescence-Free Biosensor Methods in Detection of Food Pathogens with a Special Focus on Listeria monocytogenes

Food pathogens contaminate food products that allow their growth on the shelf and also under refrigerated conditions. Therefore, it is of utmost importance to lower the limit of detection (LOD) of the method used and to obtain the results within hours to few days. Biosensor methods exploit the available technologies to individuate and provide an approximate quantification of the bacteria present in a sample. The main bottleneck of these methods depends on the aspecific binding to the surfaces and on a change in sensitivity when bacteria are in a complex food matrix with respect to bacteria in a liquid food sample. In this review, we introduce surface plasmon resonance (SPR), new advancements in SPR techniques, and electrochemical impedance spectroscopy (EIS), as fluorescence-free biosensing technologies for detection of L. monocytogenes in foods. The application of the two methods has facilitated L. monocytogenes detection with LOD of 1 log CFU/mL. Further advancements are envisaged through the combination of biosensor methods with immunoseparation of bacteria from larger volumes, application of lab-on-chip technologies, and EIS sensing methods for multiplex pathogen detection. Validation efforts are being conducted to demonstrate the robustness of detection, reproducibility and variability in multi-site installations.