Total Number Of Colonies Research Articles

Anti-fungal effects of slightly acidic electrolyzed water on Candida species

ObjectivesSlightly acidic electrolyzed water (SAEW) is produced by electrolyzing 2–6% diluted hydrochloric acid in a membrane-less chamber, resulting in 5.0–6.5 pH, and can be applied to various foods as a disinfectant. Although SAEW has shown to have bactericidal activity, the details of its anti-fungal effects towards Candida species remain unknown. Therefore, we examined the fungicidal effects of SAEW on Candida spp. and biofilms on acrylic resins. MethodsThe fungicidal effects of SAEW on Candida spp. at different reaction times and total numbers of colonies in culture plates were examined. Subsequently, SAEW was added to Candida spp. biofilms formed on polystyrene plates, and adenosine triphosphate (ATP) in SAEW was measured to examine its fungicidal effects towards Candida spp. biofilms. The fungicidal effect of SAEW on Candida spp. biofilms was determined by counting the number of colonies on the acrylic resin after adding SAEW. ResultsSAEW completely killing activity within 1 min with the tested Candida spp.. C. albicans and C. glabrata ATP were increased 5 min after adding SAEW compared with the controls, suggesting the removal of biofilm. Of the C. albicans on acrylic resin, > 99.9%were killed by SAEW compared to their levels in deionized distilled water (DW) (76.2x102/mL and 43.3x102/mL, respectively). Similarly, 93.1% of C. glabrata were killed by SAEW compared to DW (159.3x102/mL). ConclusionsSAEW may be useful in preventing oral candidiasis as part of oral care.

A Fluorescent Polyvinyl Alcohol Film with Efficient Photodynamic Antimicrobial Performance Enabled by Berberine/Phytic Acid Salt for Food Preservation

AbstractFood packaging that impedes microbial growth and can be safely used is critical to attenuate food spoilage. Herein, a green berberine/phytate salt (BPA) is successfully synthesized and aggregated in polyvinyl alcohol (PVA) film to impart fluorescent and photodynamic antimicrobial properties. Compared to berberine hydrochloride (BHL), BPA exhibited stronger fluorescence because intramolecular motions and intermolecular π–π accumulation of BHL are restricted by phytic acid (PA). Molecular dynamics simulation indicate that aggregation of BHL and PA formed through electrostatic interactions in the PVA matrix due to the change of the binding energy during the drying process. With increasing BPA content, the films exhibited increased ultraviolet, water vapor, and oxygen barriers and fluorescent properties, but reduced tensile strength and elongation at break. After radiated, PVA‐BPA9 film showed the highest antimicrobial rates against Staphylococcus aureus, Escherichia coli, P. citrinum, and Aspergillus niger reached 100%, 100%, 86.14%, and 66.24%, respectively, due to the increased reactive oxygen species production. The total number of microbial colonies in cooked chicken and oranges packaged by PVA‐BPA9 film with irradiation ARE 87.54% and 29.21% of those by PVA film. The findings indicate a new and feasible strategy to obtain a green photodynamic‐mediated film for safe and effective food packaging.

SOS1 Inhibition Enhances the Efficacy of KRASG12C Inhibitors and Delays Resistance in Lung Adenocarcinoma.

The clinical effectiveness of KRASG12C inhibitors (G12Ci) is limited both by intrinsic and acquired resistance, necessitating the development of combination approaches. Here, we identified targeting proximal receptor tyrosine kinase (RTK) signaling using the SOS1 inhibitor (SOS1i) BI-3406 as a strategy to improve responses to G12Ci treatment. SOS1i enhanced the efficacy of G12Ci and limited rebound RTK/ERK signaling to overcome intrinsic/adaptive resistance, but this effect was modulated by SOS2 protein levels. G12Ci drug tolerant persister (DTP) cells showed up to a 3-fold enrichment of tumor initiating cells (TIC), suggestive of a sanctuary population of G12Ci resistant cells. SOS1i re-sensitized DTPs to G12Ci and inhibited G12C-induced TIC enrichment. Co-mutation of the tumor suppressor KEAP1 limited the clinical effectiveness of G12Ci, and KEAP1 and STK11 deletion increased TIC frequency and accelerated the development of acquired resistance to G12Ci, consistent with clinical G12Ci resistance seen with these co-mutations. Treatment with SOS1i both delayed acquired G12Ci resistance and limited the total number of resistant colonies regardless of KEAP1 and STK11 mutational status. Together, these data suggest that targeting SOS1 could be an effective strategy to both enhance G12Ci efficacy and prevent G12Ci resistance regardless of co-mutations.

Optimisation of Lactobacillus fermentation conditions and its application in the fermentation of salt-free sauerkraut.

To identify what are the dominant lactic acid bacteria (LAB) involved in the fermentation of salt-free sauerkraut, and optimize its industrial culture conditions, we isolated and identified a strain of LAB, which is referred to as Lactobacillus sp. DF_001, with the preservation number CCTCC NO: M20232593, from five different regions in Guizhou Province. Industrial culture conditions were optimized using Plackett-Burman and Central Composite design experiments, and the potential role of this LAB in salt-free sauerkraut fermentation was validated. Bioproduction was optimal with a culture time of 66 h, starch/water ratio of 1.7% and inoculum of 0.02%, which gave approximately three-fold higher yield than the basal culture medium DeMan-Rogosa-Sharpe medium (MRS). The LAB was used in small-scale industrial experiments. The Dafang LAB significantly enhanced the sensory score of the salt-free sauerkraut products by about 32% compared to the control group. The total acid content increased by about 32% and the sugar and nitrite contents were reduced by 67.27 and 69.58%, respectively. The total number of bacterial colonies decreased by 37.5%. All other indicators complied with the national standard, providing overall the basis to improve salt-free sauerkraut fermentation.

Alginate-based edible coating with magnoliae essential oil/β-cyclodextrin inclusion complex for Kyoho grape preservation

To prolong the shelf life of Kyoho grapes at room temperature, an edible coating composed of sodium alginate (SA) containing an inclusion complex of Magnoliae essential oil (MEO) and β-cyclodextrin (β-CD) (SA/MEO@β-CD coating) was developed. Initially, the inclusion complex of MEO with β-CD was developed to enhance its thermal stability. MEO@β-CD was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). In addition, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results show that β-CD can improve the thermal stability of MEO. The entrapment efficiency and loading efficiency were 82.56% and 8.8%. MEO@β-CD was added to the SA coating for preserving Kyoho grapes, while monitoring the enzyme activity, total bacterial count, and sensory characteristics of the grapes. Compared to the uncoated group, the SA/MEO@β-CD coated group exhibited a significant reduction in total color difference, decay rate, weight loss rate, enzyme activity, and total number of bacterial colonies, while also slowing the decline in hardness and total soluble solids. The effect of the SA/MEO@β-CD1 group was highly effective. Conclusively, the SA/MEO@β-CD coating preserves Kyoho grapes by reducing lipid oxidation and inhibiting microbial growth, demonstrating its potential as an advanced edible packaging solution for grape preservation.

Encapsulation of lemongrass essential oil by bilayer liposomes based on pectin, gum Arabic, and carrageenan: Characterization and application in chicken meat preservation

The volatile characteristics of lemongrass essential oil (LO) have seriously hindered its further application, and encapsulation it with multilayer modified liposomes may be an effective strategy to improve this dilemma. This study selected chitosan (CH) and three anionic polymers, pectin (P) / gum arabic (GA) / carrageenan (C), as the first and second coating polymers to modify nano liposomes (NL) by layer-by-layer electrostatic deposition, obtaining three bilayer liposomes, P-CH-NL, GA-CH-NL, and C-CH-NL as high-quality stabilized carriers of LO. The bilayer liposomes showed a dense membrane structure ranging from 110 to 150 nm uniformly, with good antioxidant properties. All bilayer liposomes had good stability during 28-day storage at 4 °C, while C-CH-NL performed relatively better inferred by smaller changes of size, PDI and Zeta potential. The total volatile base nitrogen (TVB-N) values of fresh chicken meat and a total number of bacterial colonies (TBC) experiments showed that GA-CH-NL and C-CH-NL could better retard the increase of volatile salt base nitrogen. All bilayer liposomes could delay the time for the total bacterial count to exceed 6 log CFU/g (from 7 days to 10 / 12 days). Therefore, the bilayer liposomes P-CH-NL, GA-CH-NL, and C-CH-NL may be promising natural preservatives for food products.

Effect of oyster mushroom on nutritional composition, shelf life and organoleptic characteristics of enriched cookies

The objective of the study was to formulate functional cookies enriched with oyster mushroom and to monitor the impact of enrichments on organoleptic attributes, nutritional composition, and shelf-life studies. Three different level i.e., 3 %, 5 % and 7 % of incorporation of oyster mushroom were formulated and organoleptic evaluation was carried out while comparing with control (C- without oyster mushroom). Among them, 3 % (C1) showed the highest score of overall acceptability (8.3 ± 0.69) and it was analyzed for nutritional composition along with the control cookie (C). Enriched cookies possessed higher nutritional profile in comparison to control cookies in terms of protein, fiber, vitamin D, folic acid as well as minerals such as iron, calcium, zinc, and magnesium. Antioxidant activities were found to be 33.23 % and 1.78 umol in terms of DPPH and FRAP assays, higher than control cookies.The total number of bacterial colonies in aluminium ziploc bag were lower than the rest of packaging materials after one month of storage.Hence, it can be concluded that formulated mushroom cookies showed compositional, functional and high nutritional properties and can be stored for a month with minimum growth of microbial activity.

The impact of barbecue pickling materials on flavor changes and storage quality of pork at different processing stages

Abstract In order to enhance the aroma and flavor of pork and improve the water retention and binding power of pork, the effects of sensory score, TBARS, TVB-N, total number of colonies, water distribution, color and storage time on pork were studied. SPME-GC-MS was used to detect the flavor changes at different processing stages. The results showed that the storage time of pork products could be extended for 6d after 12 days. Meanwhile, the volatile flavor components of pork before, after and after curing were 71, 54 and 59. After curing, the types of aldehydes and alkenes increased significantly. It can be concluded that the addition of pickling materials can effectively slow down the oxidation of pork lipids and proteins, inhibit the growth of microorganisms, and extend the shelf life. It can significantly improve pork flavor and reduce the production of harmful substances such as acrylamide and polycyclic aromatic hydrocarbons.

Antioxidant and preservation effects of tea polyphenols on apple juice

Tea polyphenols (TP), a natural ingredient recognized for their potent antioxidant and antimicrobial properties, are the focus for extending the freshness and shelf life of apple juices in preservation. This study evaluated the nutritional quality, microbial growth, and sensory changes in apple juice during storage, examining the impact of TP addition on both freshly pressed and retail high-pressure processing (HPP) apple juice. For fresh apple juice, the growth of total colonies was predicted using a Modified Gompertz model. The results showed that the addition of 0.6 g/kg TP to fresh apple juice reduced the total number of colonies by 1.54 times after 11 days of storage, while the addition of 0.6 g/kg TP to retail HPP apple juice reduced the total number of colonies by 2.15 times after 20 days. In addition, apple juice treated with 0.6 g/kg of TP had good antioxidant and sensory properties compared to the control. These results indicated that the application of TP could increase the antioxidant capacity of apple juice, enhance their taste and prolong their shelf life.

Local Production of World Health Organization Recommended Hand Rub Formulation and Comparison of its Efficacy with a Commercially Available Alcohol-Based Hand Rub

Objective: To produce a World Health Organization (WHO)-recommended hand rub formulation locally and compare its efficacy with a commercially available Alcohol-based Hand Rub (ABHR) - Sterillium. Methods: A non-randomized comparative study was conducted. Sixty healthcare workers were divided into two groups - Group A (WHO-recommended hand rub) and Group B (Sterillium). WHO-recommended hand rub was prepared according to the specified formula. Each participant from study Group A received three ml of WHO-recommended hand rub formulation, and each study Group B participant received three ml of Sterillium. Bacterial samples of each participant (from both hands) were collected before and 0 after using an ABHR solution. Samples were inoculated on the nutrient agar plates and incubated at 37 C for 24 hours. The total number of bacterial colonies grown on plates inoculated before and after ABHR use was counted and identified by standard microbiology techniques and compared between the two groups. The WHO-recommended hand rub and Sterillium were compared and analyzed using differences in proportion. Results: The overall reduction in bacterial growth was comparable for both the hand rubs, with an average load reduction of log 1.5607 for locally produced hand rub solution and an average load reduction of log 1.609 in the case of Sterillium. Conclusion: Both of the handrubs are comparable in efficacy and are effective against all the bacteria isolated from the palms of HCWs (Coagulase Negative Staphylococcus (CoNS), Micrococcus spp., Acinetobacter spp., Bacillus spp., Pseudomonas spp., and Citrobacter), including Methicillin-Sensitive Staphylococcus aureus

Effects of bacterial cellulose/thyme essential oil emulsion coating on the shelf life of chilled chicken meat.

Bacterial cellulose (BC) is a fiber substance produced by microbial fermentation. It is widely used in the food preservation industry because of its extremely pure texture, high crystallinity and high biocompatibility. In the present study, bacterial cellulose/thyme essential oil (BC/TEO-E) with antibacterial and fresh-keeping functions was prepared by ultrasonic treatment of modified bacterial cellulose for encapsulation of thyme essential oil, which effectively inhibited the spoilage of chilled chicken. The purified BC, produced by Acetobacter xylinum ATCC 53524, was ultrasonically treated wih different times (0, 30, 60 and 90 min). Transmission electron microscopy, scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and zeta potential were used to characterize the structure of BC after ultrasound, showing that BC, treated for 30 min, had the optimal fiber structure, crystallinity (85.8%), thermal stability (347.77 °C) and solution stability (-26.63 ± 1.96 mV). BC/TEO-E was prepared by a homogenizer for the preservation of chilled chicken. Optical microscopy indicated that the BC/TEO-E prepared by 0.5% BC had optimal dispersion and stability, and even no delamination was observed in the emulsion. Compared with other groups (control, 0.5% BC and Tween-E), the total number of colonies and coliforms in chilled chicken treated with 0.5% BC/TEO-E was the lowest during the whole storage period (12 days), indicating that it can effectively inhibit bacterial growth. In addition, total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances, pH and drip loss results showed that 0.5% BC/TEO-E could effectively inhibit the spoilage of chilled chicken compared to the other treatment groups. All of the results acquired in the present study indicate that BC/TEO-E has a potential application in chilled chicken preservation. © 2024 Society of Chemical Industry.

Transcriptome Analysis of the Preservation Effect of Three Essential Oil Microcapsules on Okra

Cinnamon (Cinnamomum sp.) essential oil microcapsules, oregano (Origanum sp.) essential oil microcapsules, and oregano–thyme (Thymus sp.) essential oil microcapsules are rarely used in the postharvest preservation treatment of okra (Abelmoschus esculentus L.). The mechanism of these three essential oil microcapsules on the postharvest preservation of okra is also not yet well understood. In this study, fresh okra was preserved by three kinds of essential oil microcapsules (cinnamon essential oil microcapsules, oregano essential oil microcapsules, and oregano–thyme essential oil microcapsules). The effect of essential oil microcapsules on the postharvest storage quality of okra was discussed. We also used RNA-Seq to preliminarily explore the mechanism of oregano–thyme essential oil microcapsules on the pre-harvest storage quality of okra. The results showed that the three kinds of essential oil microcapsules could maintain the high sensory evaluation quality and firmness of okra, slow down the increase in respiratory intensity, slow down the total number of colonies on the fruit surface, and slow down weight loss. Through analysis, it was found that the effect of oregano–thyme essential oil microcapsules was remarkably better than that of cinnamon essential oil microcapsules and oregano essential oil microcapsules. The preservation mechanism of oregano–thyme essential oil microcapsules on postharvest okra was preliminarily elucidated by RNA-Seq. This study provides a certain basis for a follow-up study of essential oil microcapsules in the preservation of okra.

Comparing the Effects of Two Culture Methods to Determine the Total Heterotrophic Bacterial Colony Count in Hospital Purified Water

BackgroundAccurately detecting the quantity of microorganisms in hospital purified water is of significant importance for early identification of microbial contamination and reducing the occurrence of water-borne hospital infections. The choice of detection method is a prerequisite for ensuring accurate results. Traditional Plate Count Agar (PCA) belongs to a high-nutrient medium, and there may be limitations in terms of accuracy or sensitivity in detecting microorganisms in hospital purified water. On the other hand, Reasoner’s 2A agar (R2A) has characteristics, such as low-nutrient levels, low cultivation temperature, and extended incubation time, providing advantages in promoting the growth of aquatic microorganisms. This study, through comparing the differences in total colony counts between two detection methods, aims to select the method more suitable for the growth of aquatic microorganisms, offering new practical insights for accurately detecting the total count of heterotrophic bacteria in hospital purified water.MethodsThe most commonly used plate count agar (PCA) method, and the R2A agar culture were adopted to detect microorganisms and determine the total number of bacterial colonies in the water for oral diagnosis and treatment water and terminal rinse water for endoscopes in medical institutions. The two water samples were inoculated by pour plate and membrane filtration methods, respectively. Using statistical methods including Spearman and Pearson correlation, Wilcoxon signed-rank sum test, paired-Chi-square test, and linear regression, we analyze the differences and associations in the bacterial counts cultivated through two different methods.ResultsIn 142 specimens of the water, the median and interquartile range of the heterotrophic bacterial colony number under the R2A culture method and under the PCA culture method were 200 (Q1–Q3: 25–18,000) and 6 (Q1–Q3: 0–3700). The total number of heterotrophic bacteria colonies cultured in R2A medium for 7 days was more than that cultured in PCA medium for 2 days (P < 0.05). The linear regression results showed a relatively strong linear correlation between the number of colonies cultured by the R2A method and that cultured by the PCA method (R2 = 0.7264). The number of bacterial species detected on R2A agar medium is greater than that on PCA agar medium.ConclusionThe R2A culture method can better reflect the actual number of heterotrophic bacterial colonies in hospital purified water. After logarithmic transformation, the number of colonies cultured by the two methods showed a linear correlation.

Antibacterial mechanism of slightly acidic electrolyzed water against Pseudomonas arsenicoxydans A1 from greater amberjack (Seriola dumerili)

This study aimed to identify the specific spoilage organism (SSO) from the metamorphosed greater amberjack (Seriola dumerili) fish. Pseudomonas arsenicoxydans A1 was identified as SSO by culture-depending method. Further, the antibacterial efficacy of slightly acidic electrolyzed water (SAEW) was explored and the mechanism of action on P. arsenicoxydans A1 was studied. SAEW with 20–60 mg/L of available chlorine concentration (ACC) showed a good antibacterial effect on P. arsenicoxydans A1. The total number of colonies, growth curve, OD value at 260 nm and 280 nm, DNA fluorescence intensity, alkaline phosphatase (AKP), lactate dehydrogenase (LDH), superoxide dismutase (SOD), and catalase (CAT) enzyme activity and SEM results showed that SAEW could destroy the permeability and integrity of P. arsenicoxydans A1 cell membrane, and affect bacterial cell activity at metabolic, enzymatic and DNA level, which caused bacterial cell death. This study provided the application of SAEW in sterilization and preservation of raw fish fillets, which showed a promising effect on the growth of P. arsenicoxydans A1 in food cold chain.

Preparation and characterization of peach gum/chitosan polyelectrolyte composite films with dual cross-linking networks for antibacterial packaging

Peach gum (PG) is a valuable polymeric feedstock for developing eco-friendly, bio-safe, and functional materials. However, PG has limited use in food packaging due to its inferior mechanical and antibacterial properties. To overcome these limitations, we created a dual cross-linked network by introducing chitosan (CS) and glycerol to the PG matrix. Our research discovered that incorporating CS into the PG matrix significantly improved its Young's modulus, from 277.62 to 925.89 MPa, and its tensile strength from 5.96 to 39.94 MPa. Furthermore, the inclusion of glycerol greatly increased the elongation. These enhancements were attributed to the ionic and hydrogen-bonding interactions between the two biopolymers. Additionally, the composite films exhibited strong antibacterial effects, reducing the total number of colonies by 99.2 % and 99.9 % against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. The incorporation of CS resulted in more amorphous films, enhancing their stiffness, flexibility, and barrier properties. To assess the practical application of PG/CS composite films, we conducted a comparative analysis between non-packaged strawberries and strawberries packaged with these films. The results demonstrated that the composite polyelectrolyte film extended the shelf life of strawberries better than the non-packaged fruits.

Physicochemical properties and pork preservation effects of lotus seed drill core powder starch-based active packaging films

Lotus seed drill core powder starch (LCPS)-based active packaging films incorporated with cellulose nanocrystals (CNC) and grapefruit essential oil-corn nanostarch Pickering emulsion (ECPE) were characterized, and their pork preservation effects were investigated in this study. In contrast with corn, potato and rice starches, LCPS showed higher amylose content, elliptical and circular shape with more uniform size distribution. Furthermore, LCPS film exhibited lower light transmittance, stronger tensile strength, and smaller elongation at break compared to the other starch films. Then, the LCPS film containing 4 % CNC and 9 % ECPE was fabricated which had stronger mechanical properties, lower water vapor permeability and oxygen transmission rate, and denser network structure. FTIR and XRD analyses also confirmed that CNC and ECPE were successfully implanted into the LCPS matrix without damaging the crystalline structure of LCPS. Herein, the LCPS/CNC/ECPE film exerted potential antibacterial activity against Escherichia coli and Staphylococcus aureus. Besides, packaging with this composite film significantly preserved the pork during cold storage via decreasing its juice loss rate, pH value, total number of colonies, total volatile base nitrogen and thiobarbituric acid reactive substance values. The present study will provide a theoretical basis for the application of LCPS as new biodegradable active films.

Investigation of Prototheca bovis Infection and Its Correlation with Dairy Herd Improvement Data from a Dairy Farm in Central China.

Prototheca bovis (P. bovis), an alga that has attracted considerable attention over the years as a causative microorganism of mastitis in dairy cows, exhibits limited susceptibility to specific aminoglycosides and antifungal agents, and no effective clinical treatment is currently available, thereby posing challenges for both prevention and treatment. To investigate the infection of P. bovis mastitis and its impact on raw milk production, a total of 348 raw milk samples were collected from August to December 2022 from a dairy farm in central China. P. bovis and other bacteria were detected, and the average infection rate of P. bovis in raw milk was 60.34% (210/348). The total number of colonies and the somatic cell count (SCC) of P. bovis positive samples were significantly higher than those of P. bovis negative samples (p < 0.01). The daily milk yield, 305-day milk yield, peak milk yield, and days to peak milk yield of the P. bovis positive samples were significantly lower than those of P. bovis negative samples (p < 0.01). A correlation analysis showed that P. bovis infection was negatively correlated with daily milk yield, 305-day milk yield, peak milk yield, and days to peak milk yield (p < 0.0001), while being positively correlated with the total number of colonies, SCC, milk loss, and protein percentage (p < 0.0001). These findings may help practitioners in comprehending the occurrence of Prototheca mastitis and developing more effective strategies for the prevention of P. bovis infections.

Key biological processes and essential genes for Proteus mirabilis biofilm development inhibition by protocatechuic acid

Proteus mirabilis is an opportunistic pathogen linked to human urinary tract infections, and is potentially present as a foodborne pathogen within poultry products, including broiler chickens. This report outlines the inhibitory impacts of protocatechuic acid (PCA) on P. mirabilis isolated from a broiler slaughterhouse in China as well as its biofilm. This investigation encompasses assays related to motility and adhesion, bacterial metabolic activity, extracellular polymer (EPS) production, and scavenging capacity. The findings demonstrated that PCA reduced biofilm formation by 61 %. Transcriptomics findings identified that PCA limited the expression of genes like PstS that promote adhesin formation, rbsA and RcsB that alter bacterial chemotaxis, lipopolysaccharide synthesis genes LpxA and EptB, and cell wall synthesis genes MurF and MrdA, and affects the Regulator of Capsule Synthesis (RCS) two-component modulation system. Weighted gene co-expression network analysis (WGCNA) was conducted to identify the core genes. Furthermore, the binding sites of PCA to cytochrome oxidases cydA and cydB, two subunits of ATP synthase atpI and atpH, and ftsZ, which regulate bacterial division, were predicted via molecular docking. Metabolome analysis determined that PCA critically influenced coenzyme A biosynthesis, nucleotide metabolism, alanine, aspartic acid, and glutamate metabolic pathways of P. mirabilis. Therefore, PCA impacts metabolism within bacteria via various pathways, limiting the levels of extracellular polymer and bacterial viability to hinder biofilm formation. Additionally, we prepared an antibacterial plastic film containing protocatechuic acid using PVA as the monomer and CNC as the reinforcing agent. We examined the mechanical and antibacterial properties of this film. When used to wrap chicken, it reduced the total number of colonies, slowed the deterioration of chicken, and maintained the freshness of chicken. In conclusion, the information outlined in this study complements our comprehension of P. mirabilis inhibition by PCA and provides clues for the reduction of foodborne infections associated with P. mirabilis.

Preparation and characterization of starch/PBAT film containing hydroxypropyl-β-cyclodextrin/ethyl lauroyl arginate/cinnamon essential oil microcapsules and its application in the preservation of strawberry

Cinnamon essential oil (CEO) was emulsified by hydroxypropyl-β-cyclodextrin/ ethyl lauroyl arginate (HPCD/LAE) complex to make nanoemulsions, which were then incorporated into maltodextrin (MD) to prepare HPCD/LAE/CEO/MD microcapsules by spray drying. The starch/polybutylene adipate terephthalate (starch/PBAT, SP) based extrusion-blowing films containing above microcapsules were developed and used as packaging materials for strawberry preservation. The morphology, encapsulation efficiency, thermal and antibacterial properties of microcapsules with different formulations were investigated. The effects of microcapsules on the physicochemical and antimicrobial properties of SP films were evaluated. When the formula was 4 % HPCD/LAE-3% CEO-10% MD (HL-3C-MD), the microcapsule had the smallest particle size (3.3 μm), the highest encapsulation efficiency (84.51 %) of CEO and the best antibacterial effect. The mechanical and antimicrobial properties of the SP film were enhanced while the water vapor transmittance and oxygen permeability decreased with the incorporation of HL-3C-MD microcapsules. The films effectively reduced the weight loss rate (49.03 %), decay rate (40.59 %) and the total number of colonies (2.474 log CFU/g) and molds (2.936 log CFU/g), thus extending the shelf life of strawberries. This study revealed that the developed SP films containing HPCD/LAE/CEO microcapsules had potential applications in degradable bioactive food packaging materials.

Kinetics of sterilization of atomized slightly acidic electrolyzed water on tableware

The aim of this study was to elucidate the kinetics of atomization of slightly acidic electrolyzed water (SAEW) for use in sterilization of secondary contaminated tableware surfaces. The sterilization efficacy of SAEW was assessed on the basis of the change in the total number of colonies with different contamination levels (101 CFU/mL and 102 CFU/mL), atomization time (10, 20, 30, 40, and 50 s), atomizing distance (5, 10, 15, 20, 25, and 30 cm), and available chlorine concentration (ACC; 25.2, 30.2, 34.9, 40.5, 44.8, and 53.3 mg/L) as the main influencing factors. According to the relationship among flux, atomization area, and time, a kinetic model of SAEW atomization for the sterilization of tableware surfaces was established. The results indicated that the sterilization efficacy of SAEW gradually improved with decreased contamination levels (12.69 %–15.74 %), extended atomization time (13.68 %–46.58 %), and increased ACC (36.89 %–95.14 %). Based on the kinetics analysis, the change law of the kinetic model of SAEW atomization and sterilization of tableware surfaces with secondary pollution was found to be consistent with the change law of sterilization (r2 > 0.8). The results of this study provide a theoretical basis for SAEW atomization for sterilization of secondary contaminated tableware surfaces and also contributes to the improvement of technological theory of SAEW sterilization.