One of the key mechanisms enabling bacterial cells to create biofilms and regulate crucial life functions in a global and highly synchronized way is a bacterial communication system called quorum sensing (QS). QS is a bacterial cell-to-cell communication process that depends on the bacterial population density and is mediated by small signalling molecules called autoinducers (AIs). In bacteria, QS controls the biofilm formation through the global regulation of gene expression involved in the extracellular polymeric matrix (EPS) synthesis, virulence factor production, stress tolerance and metabolic adaptation. Forming biofilm is one of the crucial mechanisms of bacterial antimicrobial resistance (AMR). A common feature of human pathogens is the ability to form biofilm, which poses a serious medical issue due to their high susceptibility to traditional antibiotics. Because QS is associated with virulence and biofilm formation, there is a belief that inhibition of QS activity called quorum quenching (QQ) may provide alternative therapeutic methods for treating microbial infections. This review summarises recent progress in biofilm research, focusing on the mechanisms by which biofilms, especially those formed by pathogenic bacteria, become resistant to antibiotic treatment. Subsequently, a potential alternative approach to QS inhibition highlighting innovative non-antibiotic strategies to control AMR and biofilm formation of pathogenic bacteria has been discussed.

Bacteriophages are viruses that are ubiquitous in nature and infect only bacterial cells. These organisms are characterized by high specificity, an important feature that enables their use in the food industry. Phages are applied in three sectors in the food industry: primary production, biosanitization, and biopreservation. In biosanitization, phages or the enzymes that they produce are mainly used to prevent the formation of biofilms on the surface of equipment used in the production facilities. In the case of biopreservation, phages are used to extend the shelf life of products by combating pathogenic bacteria that spoil the food. Although phages are beneficial in controlling the food quality, they also have negative effects. For instance, the natural ability of phages that are specific to lactic acid bacteria to destroy the starter cultures in dairy production incurs huge financial losses to the dairy industry. In this paper, we discuss how bacteriophages can be either an effective weapon in the fight against bacteria or a bane negatively affecting the quality of food products depending on the type of industry they are used.

Nowadays, people are exposed to diverse environmental and chemical pollutants produced by industry and agriculture. Food contaminations such as persistent organic pollutants (POPs), heavy metals, and mycotoxins are a serious concern for global food safety with economic and public health implications especially in the newly industrialized countries (NIC). Mounting evidence indicates that chronic exposure to food contaminants referred to as xenobiotics exert a negative effect on human health such as inflammation, oxidative stress, and intestinal disorders linked with perturbation of the composition and metabolic profile of the gut microflora. Although the physicochemical technologies for food decontamination are utilized in many cases but require adequate conditions which are often not feasible to be met in many industrial sectors. At present, one promising approach to reduce the risk related to the presence of xenobiotics in foodstuffs is a biological detoxification done by probiotic strains and their enzymes. Many studies confirmed that probiotics are an effective, feasible, and inexpensive tool for preventing xenobiotic-induced dysbiosis and alleviating their toxicity. This review aims to summarize the current knowledge of the direct mechanisms by which probiotics can influence the detoxification of xenobiotics. Moreover, probiotic-xenobiotic interactions with the gut microbiota and the host response were also discussed.

Gut microbiota (GM) plays many key functions and helps maintain the host’s health. Consequently, the development of GM cultivation under in vitro stimulating physiological conditions has gained extreme interest in different fields. In this study, we evaluated the impact of four culture media: Gut Microbiota Medium (GMM), Schaedler Broth (SM), Fermentation Medium (FM), and Carbohydrate Free Basal Medium (CFBM) on preserving the biodiversity and metabolic activity of human GM in batch in vitro cultures using PMA treatment coupled with 16S rDNA sequencing (PMA-seq) and LC-HR-MS/MS untargeted metabolomics supplemented with GC–MS SCFA profiling. Before the experiments, we determined the possibility of using the pooled faecal samples (MIX) from healthy donors (n = 15) as inoculum to reduce the number of variables and ensure the reproducibility of in vitro cultivation tests. Results showed the suitability of pooling faecal samples for in vitro cultivation study. Non-cultured MIX inoculum was characterized by higher α-diversity (Shannon effective count, and Effective microbial richness) compared to inocula from individual donors. After 24 h of cultivation, a significant effect of culture media composition on GM taxonomic and metabolomic profiles was observed. The SM and GMM had the highest α-diversity (Shannon effective count). The highest number of core ASVs (125) shared with non-cultured MIX inoculum and total SCFAs production was observed in the SM. These results might contribute to the development of standardized protocols for human GM in vitro cultivation by preventing methodological bias in the data.

The widespread use of antibiotics, especially those with a broad spectrum of activity, has resulted in the development of multidrug resistance in many strains of bacteria, including Salmonella. Salmonella is among the most prevalent causes of intoxication due to the consumption of contaminated food and water. Salmonellosis caused by this pathogen is pharmacologically treated using antibiotics such as fluoroquinolones, ceftriaxone, and azithromycin. This foodborne pathogen developed several molecular mechanisms of resistance both on the level of global and local transcription modulators. The increasing rate of antibiotic resistance in Salmonella poses a significant global concern, and an improved understanding of the multidrug resistance mechanisms in Salmonella is essential for choosing the suitable antibiotic for the treatment of infections. In this review, we summarized the current knowledge of molecular mechanisms that control gene expression related to antibiotic resistance of Salmonella strains. We characterized regulators acting as transcription activators and repressors, as well as two-component signal transduction systems. We also discuss the background of the molecular mechanisms of the resistance to metals, regulators of multidrug resistance to antibiotics, global regulators of the LysR family, as well as regulators of histone-like proteins.

The influence of high pressure homogenization (HPH) at 100-150 MPa performed by multiple passes below 35 °C on carrot juice quality and stability was studied. The highest reduction in microorganisms (by 2.47 log) was noted at 150 MPa with 5 passes of the juice through the homogenizer. The PPO and POD's residual activity increased after HPH; PG was at the same level, while PME activity increased or decreased depending on the process parameters used. HPH treatment resulted in a decrease in the apparent dynamic viscosity, turbidity and colour parameters. Five passes at 150 MPa caused an increase in the carotenoid content, especially 9-Z-β-carotene (by 154%) while the TPC did not change significantly. Carrot juice treatment at 150 MPa with 5 passes may extend its shelf-life by 3 days when stored at 4 °C.