Biofilm and quorum-sensing genes (csgD, agfA, adrA, bapA, sdiA, and luxS) in the planktonic Salmonella Enteritidis cells were activated by sublethal chlorine stress (350 ppm total chlorine), as demonstrated in our findings. The increased expression of these genes showed that chlorine stress induced the starting phase of biofilm formation in *S. Enteritidis*. The initial attachment assay yielded results that supported this observation. Furthermore, the count of chlorine-stressed biofilm cells exceeded that of non-stressed biofilm cells by a considerable margin following 48 hours of incubation at 37 degrees Celsius. For S. Enteritidis ATCC 13076 and S. Enteritidis KL19, the number of chlorine-stressed biofilm cells, quantified as 693,048 and 749,057 log CFU/cm2 respectively, contrasted with non-stressed biofilm cells, which were 512,039 and 563,051 log CFU/cm2, respectively. Further evidence for these findings emerged from determining the levels of the key biofilm components: eDNA, protein, and carbohydrate. The concentration of these components in 48-hour biofilms was amplified by preceding exposure to sublethal chlorine levels. However, 48-hour biofilm cells failed to demonstrate upregulation of biofilm and quorum sensing genes, signifying a waning chlorine stress effect in subsequent Salmonella generations. Sublethal chlorine concentrations were found, in these results, to encourage the biofilm-forming tendency of S. Enteritidis.

The heat-processing of foods frequently results in the presence of Anoxybacillus flavithermus and Bacillus licheniformis, which are amongst the prominent spore-forming bacteria. To our present understanding, there exists no comprehensive examination of the growth rate data for A. flavithermus or B. licheniformis. The present research explored the growth kinetics of A. flavithermus and B. licheniformis in broth solutions, investigating their behavior across a range of temperatures and pH values. Growth rates were examined, with cardinal models representing the effect of the stated factors. The estimated cardinal parameters Tmin, Topt, Tmax, pHmin, and pH1/2 for A. flavithermus were 2870 ± 026, 6123 ± 016, and 7152 ± 032 °C, 552 ± 001 and 573 ± 001, respectively, whereas B. licheniformis exhibited values of 1168 ± 003, 4805 ± 015, and 5714 ± 001 °C, with corresponding pHmin and pH1/2 values of 471 ± 001 and 5670 ± 008, respectively. An investigation into the growth patterns of these spoilers was conducted in a pea beverage, at temperatures of 62°C and 49°C, respectively, to tailor the models to this particular product. In static and dynamic validation tests, the adjusted models exhibited highly favorable performance in predicting A. flavithermus (857% accuracy) and B. licheniformis (974% accuracy), with all predictions falling within the -10% to +10% relative error (RE) range. The potential for spoilage in heat-processed foods, including plant-based milk alternatives, can be effectively assessed using the developed models, proving them useful tools.

High-oxygen modified atmosphere packaging (HiOx-MAP) presents ideal conditions for Pseudomonas fragi, an organism that significantly contributes to meat spoilage. The research explored the relationship between carbon dioxide and *P. fragi* growth, and how this impacted the spoilage of beef preserved via HiOx-MAP. P. fragi T1, a strain noted for its potent spoilage capacity among isolates, was used to incubate minced beef, which was then stored under CO2-enriched HiOx-MAP (TMAP; 50% O2/40% CO2/10% N2) or non-CO2 HiOx-MAP (CMAP; 50% O2/50% N2) at 4°C for 14 days. The TMAP treatment, unlike CMAP, maintained satisfactory oxygen levels in beef, which contributed to a higher a* value and improved meat color stability, linked to a decrease in P. fragi counts from the start (P < 0.05). Fimepinostat TMAP samples showcased a statistically lower (P<0.05) level of lipase activity compared to CMAP samples within 14 days, and a similarly significant (P<0.05) decrease in protease activity within 6 days. The substantial increase in pH and total volatile basic nitrogen content in CMAP beef during storage was deferred by the use of TMAP. Fimepinostat Lipid oxidation was markedly increased by TMAP, leading to higher concentrations of hexanal and 23-octanedione than CMAP (P < 0.05). Despite this, TMAP beef preserved an acceptable odor profile, a consequence of CO2's inhibition of the microbial formation of 23-butanedione and ethyl 2-butenoate. This research presented a complete examination of CO2's antibacterial mechanisms for P. fragi in the presence of HiOx-MAP beef.

Brettanomyces bruxellensis, with its adverse effect on the organoleptic characteristics of the wine, is considered the most damaging spoilage yeast in the wine industry. The continued presence of wine contaminants in cellars over extended periods, often recurring, indicates the existence of particular properties that allow for persistence and environmental survival, aided by bioadhesion mechanisms. This work examined the physicochemical surface characteristics, morphology, and the ability of these materials to adhere to stainless steel, both in synthetic solutions and wine. Genetic diversity within the species was represented by over fifty strains, which were included in the study. Microscopic investigations brought to light a considerable morphological variety among cells, with some genetic groups characterized by the presence of pseudohyphae. A detailed examination of the cell surface's physicochemical properties uncovers distinct behaviors. Most strains exhibit a negative surface charge and hydrophilic nature, yet the Beer 1 genetic group manifests hydrophobic tendencies. All strains displayed bioadhesion on stainless steel surfaces after only three hours, with a notable variation in cell concentration. The number of cells varied between 22 x 10^2 cells/cm2 and 76 x 10^6 cells/cm2. In summary, our results indicate a marked variability in bioadhesion properties, forming the initial stage of biofilm development, directly related to the genetic group exhibiting the strongest bioadhesion capacity, most prominent in the beer group.

Investigations and deployments of Torulaspora delbrueckii in the alcoholic fermentation of grape must are rising within the wine industry. The improvement in the taste of wines, owing to the combined action of this yeast species and the lactic acid bacterium Oenococcus oeni, is a noteworthy field of study. Using sequential alcoholic fermentation (AF), 3 strains of Saccharomyces cerevisiae (Sc) and 4 strains of Torulaspora delbrueckii (Td) were paired with 4 strains of Oenococcus oeni (Oo) for malolactic fermentation (MLF) in this comparative study of 60 yeast strain combinations. We sought to determine the positive or negative associations of these strains, aiming to identify the specific combination ensuring the best possible MLF performance. In addition to the above, a new synthetic grape must has been created to ensure the accomplishment of AF and the subsequent MLF. The Sc-K1 strain's employment in MLF is inappropriate under the stated circumstances without preliminary inoculation with Td-Prelude, Td-Viniferm, or Td-Zymaflore, always encompassing the Oo-VP41 combination. The results from the trials indicate that a sequence involving AF, Td-Prelude, and either Sc-QA23 or Sc-CLOS, followed by MLF and Oo-VP41, demonstrably demonstrated the positive effect of T. delbrueckii compared to the control of Sc alone, as illustrated by a reduction in the time required for L-malic acid consumption. Ultimately, the findings emphasize the importance of strain matching and yeast-LAB compatibility in achieving desired wine characteristics. The study also reveals a positive effect of selected T. delbrueckii strains on MLF.

Contamination of beef during processing with Escherichia coli O157H7 (E. coli O157H7), resulting in acid tolerance response (ATR), is a substantial concern regarding food safety. Consequently, to investigate the genesis and molecular underpinnings of the tolerance mechanism exhibited by E. coli O157H7 within a simulated beef processing milieu, the resistance of a wild-type (WT) strain and its corresponding phoP mutant to acidic conditions, thermal stress, and osmotic pressure was assessed. Pre-adaptation of strains was carried out utilizing varied conditions of pH (5.4 and 7.0), temperature (37°C and 10°C), and culture mediums (meat extract and Luria-Bertani broth). Subsequently, the investigation included the exploration of gene expression linked to stress response and virulence in both wild-type and phoP strains under the evaluated conditions. Exposure to an acidic environment prior to stress conferred a stronger resistance in E. coli O157H7 to acid and heat, but a reduced resistance to osmotic pressure was observed. Moreover, meat extract medium acid adaptation, mirroring a slaughterhouse environment, enhanced ATR; conversely, a prior 10°C adaptation reduced ATR. The study demonstrated a synergistic effect of mildly acidic conditions (pH 5.4) and the PhoP/PhoQ two-component system (TCS) on increasing acid and heat resistance in E. coli O157H7. The upregulation of genes associated with arginine and lysine metabolism, heat shock, and invasiveness showcased a role for the PhoP/PhoQ two-component system in the mechanisms of acid resistance and cross-protection under mildly acidic conditions. Acid adaptation and phoP gene deletion both contributed to a drop in the relative expression of the stx1 and stx2 genes, which are considered to be crucial pathogenic factors. The current findings strongly indicate that ATR is potentially feasible in E. coli O157H7 during beef processing operations. Fimepinostat Thus, the persistent tolerance response within the following processing environments poses a growing threat to food safety standards. This investigation yields a more exhaustive framework for the effective application of hurdle technology within the beef processing industry.

The chemical characteristics of wine are significantly altered by climate change, specifically manifesting as a substantial reduction in malic acid levels within the grapes. Wine professionals must investigate physical and/or microbiological solutions for managing wine acidity.