The color of mulberry wine is difficult to maintain as the primary chromogenic compounds, anthocyanins, are heavily affected by degradation during fermentation and aging. High hydroxycinnamate decarboxylase (HCDC) activity, demonstrated by Saccharomyces cerevisiae I34 (7849%) and Wickerhamomyces anomalus D6 (7871%), led to the selection of these strains to augment the development of stable vinylphenolic pyranoanthocyanins (VPAs) pigments during the course of mulberry wine fermentation. Using a deep-well plate micro-fermentation technique, 84 distinct strains originating from eight regions within China were first screened for HCDC activity. The strains' tolerance and brewing characteristics were then examined using simulated mulberry juice. Fresh mulberry juice was inoculated with the two chosen strains and a commercial Saccharomyces cerevisiae, either singly or in succession, while anthocyanin precursors and VPAs were simultaneously determined using UHPLC-ESI/MS. The HCDC-active strains, as demonstrated by the results, promoted the creation of stable pigments, including cyanidin-3-O-glucoside-4-vinylcatechol (VPC3G) and cyanidin-3-O-rutinoside-4-vinylcatechol (VPC3R), suggesting a potential for improved color retention.
3D food printers (3DFPs) facilitate the customization of food's physiochemical properties in innovative ways. Transfer mechanisms of foodborne pathogens between food inks and surfaces within 3DFPs remain unevaluated. The objective of this study was to ascertain the effect of the macromolecular makeup of food inks on the transmission of foodborne pathogens from the stainless steel ink capsule to the 3D-printed food. After inoculation with Salmonella Typhimurium, Listeria monocytogenes, and a human norovirus surrogate, Tulane virus (TuV), the interior surface of stainless steel food ink capsules was dried for 30 minutes. Finally, 100 grams of one of these four prepared inks was extruded: pure butter, a sugar solution, a protein solution, or a 111 ratio combination of the three macromolecular components. this website A generalized linear model, incorporating quasibinomial errors, was utilized to estimate the transfer rates of pathogens, following the complete enumeration of pathogens in both soiled capsules and printed food items. A robust two-way interaction was discovered between microorganism type and food ink type, marked by a highly significant p-value of 0.00002. Tulane virus transmission was most frequently observed, displaying no meaningful divergence in transmission rates between L. monocytogenes and S. Typhimurium, regardless of the specific food matrix or diverse food matrices. Within different food types, the complex mixture of ingredients yielded fewer transferred microorganisms in each experiment, whereas butter, protein, and sugar showed no statistically discernible variation in microbial transfer rates. This research is geared toward enhancing 3DFP safety and advancing the understanding of how macromolecular composition affects pathogen transfer kinetics, a previously unexplored facet in pure matrices.
Yeast contamination of white-brined cheeses (WBCs) poses a critical issue within the dairy industry. this website Yeast contaminants and their succession within white-brined cheese over a 52-week period were the focus of this investigation. this website Danish dairy facilities produced white-brined cheeses (WBC1) incorporating herbs, or (WBC2) sundried tomatoes, incubating them at 5°C and 10°C. An increase in yeast colony count was observed for both products, peaking within the first 12-14 weeks of incubation before stabilizing, with the range of 419-708 log CFU/g. An interesting finding was that higher incubation temperatures, notably within the WBC2 samples, were accompanied by a reduction in yeast counts, while the species diversity of yeasts increased. It is highly probable that the observed diminution in yeast quantities stemmed from negative interspecies interactions, which led to growth inhibition. In the course of genotypic classification, 469 yeast isolates from WBC1 and WBC2 were examined using the (GTG)5-rep-PCR technique. A subsequent analysis, involving sequencing of the D1/D2 domain of the 26S rRNA gene, identified 132 representative isolates. The white blood cells (WBCs) predominantly contained Candida zeylanoides and Debaryomyces hansenii as yeast species; Candida parapsilosis, Kazachstania bulderi, Kluyveromyces lactis, Pichia fermentans, Pichia kudriavzevii, Rhodotorula mucilaginosa, Torulaspora delbrueckii, and Wickerhamomyces anomalus were less frequently encountered. In terms of yeast species heterogeneity, WBC2 samples were typically more diverse than those in WBC1. This research indicated that the diverse taxonomy of yeast, coupled with contamination levels, is a critical factor in determining yeast cell counts and product quality during storage.
Droplet digital polymerase chain reaction, or ddPCR, is a novel molecular diagnostic technique that precisely determines the absolute quantity of target molecules. While promising in identifying foodborne microorganisms, the application of this method for tracking starter cultures within the dairy sector is underreported. Employing ddPCR, this study explored the suitability of this platform for detecting the probiotic Lacticaseibacillus casei, commonly found in fermented foods, with its known health benefits. This study also evaluated the comparative effectiveness of ddPCR and real-time PCR. The ddPCR assay targeting haloacid dehalogenase-like hydrolase (LBCZ 1793) demonstrated high specificity, effectively distinguishing it from 102 nontarget bacterial species, including closely related Lacticaseibacillus species, very similar to L. casei. The ddPCR assay exhibited both high linearity and efficiency throughout the range of 105 to 100 colony-forming units per milliliter, while maintaining a detection threshold of 100 CFU/mL. Milk samples spiked with low bacterial concentrations revealed a greater sensitivity for detection using ddPCR than real-time PCR. Beyond that, it gave an exact, absolute count of L. casei, without needing standard calibration curves. Employing ddPCR, this study successfully monitored starter cultures during dairy fermentations and detected the presence of L. casei in food samples.
Consumption of lettuce is a factor frequently observed in the seasonal outbreaks of Shiga toxin-producing Escherichia coli (STEC) infections. The influence of diverse biotic and abiotic factors on the lettuce microbiome's behavior is not fully known, a vital factor in understanding STEC colonization. California harvest samples of lettuce phyllosphere and surface soil, collected during late spring and fall, were analyzed metagenomically for their bacterial, fungal, and oomycete communities. A discernible effect was observed on the leaf and adjacent soil microbiome structure, arising from the interplay of harvest season and field type, while cultivar remained irrelevant. Microbiome compositions in the phyllosphere and soil demonstrated a relationship with specific atmospheric patterns. Leaves, compared to soil, exhibited a higher relative abundance of Enterobacteriaceae, but not E. coli, reaching 52%, while soil displayed only 4%. This enrichment positively correlated with minimum air temperature and wind speed. Seasonal patterns in fungi-bacteria partnerships on leaves were apparent through co-occurrence network investigations. Species correlations were, in 39% to 44% of cases, attributable to these associations. E. coli's positive co-occurrences with fungi were consistently found, and all negative correlations were present only with bacterial species. A significant portion of leaf bacteria species mirrored those present in soil, implying a microbiome transfer from the soil surface to the tree canopy. Factors influencing the microbial communities of lettuce and the role of microbes in the introduction of foodborne pathogens in the lettuce phyllosphere are explored in our research.
A surface dielectric barrier discharge was employed to create plasma-activated water (PAW) from tap water, with the discharge power modulated to 26 and 36 watts, and the activation time set at 5 and 30 minutes respectively. In planktonic and biofilm forms, the inactivation of a three-strain Listeria monocytogenes cocktail was investigated. The PAW treatment, generated at 36 W-30 minutes, displayed the lowest pH and the highest concentrations of hydrogen peroxide, nitrates, and nitrites, demonstrating exceptional efficacy in killing planktonic cells. The result was a dramatic 46-log reduction in cell count after 15 minutes of treatment. While antimicrobial efficacy within biofilms cultivated on stainless steel surfaces and polystyrene substrates was diminished, extending the exposure duration to 30 minutes facilitated inactivation exceeding 45 log cycles. Chemical solutions replicating the physicochemical properties of PAW, in conjunction with RNA-seq analysis, allowed for the investigation into the mechanisms of action behind PAW. Carbon metabolism, virulence, and general stress response genes were amongst the most affected by transcriptomic changes, with multiple overexpressed genes forming part of the cobalamin-dependent gene cluster.
Multiple parties have deliberated the longevity of SARS-CoV-2 on food surfaces and its transmission along the food chain, emphasizing that this poses significant public health risks and presents new problems for the entire food sector. For the first time, this investigation reveals the potential of edible films in countering the spread of SARS-CoV-2. Sodium alginate films, supplemented with gallic acid, geraniol, and green tea extract, were scrutinized for their ability to inhibit the replication of SARS-CoV-2. The results indicated that these films possess significant antiviral activity against this virus in laboratory settings. Conversely, the film incorporating gallic acid necessitates a considerably higher concentration (125%) of the active compound to achieve outcomes mirroring those obtained using lower concentrations of geraniol and green tea extract (0313%). In addition, storage stability of films containing a critical concentration of active compounds was evaluated.