Antimicrobial Preservatives Research Articles

Insights into the antifungal activity and mechanisms of cinnamon components against Aspergillus flavus and Penicillium citrinum

Fungal spoilage of food and the excessive use of chemical disinfectants serves potential adverse effects on human health and the environment. Consequently, there is a growing interest in exploring natural alternatives, particularly plant-derived antimicrobial preservatives. Cinnamon extracts are known for their antifungal activity, but most research has focused on essential oils, rarely on other bioactive components. This study assessed the antifungal activity and underlying mechanisms of four components—trans-cinnamaldehyde, cis-2-methoxycinnamic acid, coumarin, and o-methoxycinnamaldehyde—extracted from Cinnamomum cassia Presl (cinnamon) against Aspergillus flavus and Penicillium citrinum. These cinnamon components can inhibit the two fungi strains at the minimum inhibitory concentration ranged from 0.30 to 8.55 mmol/L. These components can disrupt fungal cell membranes by enhancing relative electrical conductivity and cytoplasmic content leakage, reducing ergosterol content, and increasing malondialdehyde level. Additionally, they can affect fungal cell wall integrity, leading to the leakage of alkaline phosphatase and alterations in the contents of β-1,3-glucan and chitin. Moreover, the cinnamon components influenced the activities of malate dehydrogenase, succinate dehydrogenase, as well as adenosine triphosphate levels. The observed suppression of fungal contamination in A. flavus and P. citrinum suggests that these cinnamon components as potential natural antifungal agents.

Nanochitosan-encapsulated melatonin: an eco-friendly strategy to delay petal senescence in cut gerbera flowers

BackgroundThe preservation of cut flowers, particularly Gerbera jamesonii, is crucial for maintaining their aesthetic value and extending vase life in the floriculture industry. To address this challenge, this study investigated the effects of melatonin (Mel) and encapsulated melatonin with nanochitosan (nCS-Mel) as preservative solutions on cut Gerbera jamesonii cv. ‘Terra kalina’ flowers. In research, we examined various physiological and biochemical parameters, including relative water content, membrane stability index, carbohydrate content, and antioxidant enzyme activities, to evaluate the efficacy of these treatments in prolonging the vase life and quality of cut gerbera flowers under controlled environmental conditions.ResultsOur results demonstrated that cut Gerbera jamesonii flowers maintained in vase solutions containing 0.1 and 0.5 mM nCS-Mel exhibited enhanced preservation of cell membrane integrity and anthocyanin content, while also maintaining higher levels of carbohydrates and total flavonoids in petals at the conclusion of their vase life. A decline in petal relative water content and protein levels was observed concomitantly with petal senescence, whereas total phenolic compounds showed an increase. The hydrogen peroxide (H2O2) content in petals exhibited an upward trend during vase life in control specimens, but this effect was mitigated in treatments containing melatonin. Although malondialdehyde (MDA) content generally increased throughout the vase life period, flowers subjected to either Mel or nCS-Mel treatments displayed reduced MDA accumulation. The activity of catalase (CAT) demonstrated an increasing trend during vase life, with the maximum activity observed in Gerbera flowers treated with 0.1 mM nCS-Mel. A similar upward trend was noted for superoxide dismutase (SOD) activity, with flowers in 0.5 mM nCS-Mel treatment exhibiting peak SOD values on day 12 relative to control and other treatments. Peroxidase (POD) activity also increased across all treatments, with particularly pronounced effects in vase solutions containing 0.1 mM Mel and nCS-Mel. Notably, flowers placed in vase solutions containing 0.1 mM nCS-Mel, followed by 0.5 mM nCS-Mel and 0.1 mM Mel, exhibited the most prolonged vase life, extending up to 12, 10.66, and 10.33 days, respectively, under room temperature conditions.ConclusionsThe application of nanoencapsulated melatonin as a vase solution for cut Gerbera jamesonii flowers demonstrates significant potential in extending vase life and maintaining flower quality through enhanced preservation of cellular integrity, antioxidant activity, and biochemical parameters. This innovative approach not only outperforms conventional treatments but also presents a more environmentally friendly alternative to traditional antimicrobial preservatives and sugars, offering a promising solution for the floriculture industry to improve cut flower longevity and reduce ecological impact.

Inhibitory effect and mechanism of violacein on planktonic growth, spore germination, biofilm formation and toxin production of Bacillus cereus and its application in grass carp preservation

Bacillus cereus is a ubiquitous foodborne pathogen commonly found in various foods. Its ability to form spores, biofilms and diarrhoeal and/or emetic toxins further exacerbates the risk of food poisoning. Violacein is a tryptophan derivative with excellent antibacterial activity. However, the knowledge on the antibacterial action of violacein against B. cereus was lacking, and thus this study aimed to investigate the antibacterial activity and mechanism. The antibacterial results demonstrated that minimum inhibitory concentration and minimum bactericidal concentration of violacein were 3.125 mg/L and 12.50 mg/L, respectively. Violacein could effectively inhibit planktonic growth, spore germination and biofilm formation of B. cereus (P < 0.001). Meanwhile, violacein significantly downregulated the expression of toxin genes, including nheA (P < 0.05), nheB (P < 0.001), bceT (P < 0.01), cytK (P < 0.001), hblC (P < 0.001) and hblD (P < 0.001). Results of extracellular alkaline phosphatase, nucleotide and protein leakage assays and scanning and transmission electron microscopy observation tests showed violacein destroyed cell walls and membranes of B. cereus. In addition, 6.25 mg/kg of violacein could significantly inhibit B. cereus in grass carp fillets (P < 0.05). These results demonstrate that violacein has great potential as an effective natural antimicrobial preservative to control food contamination and poisoning events caused by B. cereus.

Rapid detection of benzoic, sorbic, and dehydroacetic acids in processed foods using surface-enhanced Raman scattering spectroscopy

Benzoic acid (BA), sorbic acid (SA), and dehydroacetic acid (DHA) are among the most common food additives that are classified as antimicrobial preservatives. However, their consumption in excess can lead to damage to the human liver and kidneys. At the present time, no rapid method has been developed for the simultaneous detection of these preservatives in processed foods. In this study, an expedited process based on surface-enhanced Raman scattering (SERS) and solid-phase extraction (SPE) has been developed to determine the content of the preservatives in processed seafood, minced fish, and cheese products. The effect of local heating on SERS spectra at the center of the droplet, which was deposited onto silver nanopillar arrays used as the SERS substrate, was examined. A recirculating flow, manifested as twin vortices merging within the droplet, brought the preservative molecules down to the droplet’s center, resulting in an increase in the SERS signals. Furthermore, the screening efficiency of the detection method for the three preservatives was experimentally evaluated in real samples. The experimentally determined Raman bands of the added BA, SA, and DHA were compared with amounts obtained by the conventional method of high-performance liquid chromatograph (HPLC).

A Radish Root Ferment Filtrate for Cosmetic Preservation: A Study of Efficacy of Kopraphinol

Preserving cosmetic products from microbial contamination is crucial to ensuring their safety, efficacy, and shelf life. A number of synthetic antimicrobial preservatives are available, but, since the global market demand for natural ingredients is increasing, cosmetic manufacturers are considering replacing conventional preservatives with natural alternatives. In this context, the objective of this investigation was to characterize the antimicrobial activity of the natural preservative, intended for cosmetic purposes, Kopraphinol (INCI name: Lactobacillus/Radish Root Ferment Extract Filtrate). It was tested against a panel of selected bacteria and mycetes by using conventional microbiological techniques (determination of MIC, time killing assay), and a challenge test was used to verify its potential preservative in an O/W hydrophilic cream (Cetomacrogol cream base). Kopraphinol has shown an interesting antimicrobial effectiveness, with M.I.C.s ranging from 0.78% to 6.25% for bacteria and from 1.56% to 5% for mycetes. Moreover, it fulfilled challenge test criterion A and has proven effective against microbial contamination, leading to a 3 log reduction of inoculum after 7 days for bacteria and a 2 log reduction at 14 days for fungi. The results obtained show that Kopraphinol can be considered a promising and effective candidate for the antimicrobial preservation of cosmetics and could successfully complement or even replace conventional preservatives.

Gas repellents herbal drugs could induce hyperkalemia in infants: case series in tertiary centers in Saudi Arabia

This is a case series involving four infants who experienced hyperkalemia (high levels of potassium in the blood) after using herbal gas repellents that contained potassium sorbate as an antimicrobial preservative. The first patient was a ten-day-old male who presented with jaundice and incidental hyperkalemia, which resolved with treatment. The second patient was a three-month-old male who had a history of neonatal critical care admission and presented with vomiting and incidental hyperkalemia, which resolved spontaneously. The third patient was a two-month-old female who presented with failure to thrive and incidental hyperkalemia, which resolved after discontinuation of the herbal gas repellent. The fourth patient was a one-month-old male who presented with vomiting and incidental hyperkalemia, which also resolved after discontinuation of the herbal gas repellent. All patients underwent investigations to determine the underlying cause of hyperkalemia, but no specific cause was found other than the use of the herbal gas repellents. The abstract highlights the importance of physicians being aware of the potential effects of potassium-containing herbal gas repellents and the occurrence of unexplained hyperkalemia in infants, urging caution in their use.

Photoelectrochemical degradation of selected organic pollutants on tungsten trioxide photoanodes

This study describes the photoelectrochemical degradation of model aromatic pollutants, viz. a herbicide (“monuron”, 3-(4-chlorophenyl)-1,1-dimethylurea) and an antimicrobial preservative (benzoic acid) on WO3 films prepared by aerosol pyrolysis. Crystalline WO3 films had a monoclinic structure, 4 μm thickness and a photocurrent density of 1 mA cm−2 at 1.2 V vs. RHE and illumination under 1 sun (simulated). The chemical and photoelectrochemical stability of WO3 films at various pH was evaluated. The dissolution rate at pH 1 and 4 was low (0.5 nm·h−1), whereas at pH 6 an increase in the dissolution rate to 15 nm·h−1 was observed. The course of the photoelectrochemical oxidation of selected pollutants was examined using HPLC. The achieved Faradaic efficiency of photoelectrooxidation of 1 mM benzoic acid divided by the number of charge equivalents per 1 mol of oxidised compound R, f/z, was 13 % and 12 % at pH 1 and 4, respectively, and for 1 mM monuron 7.2 % at pH 1 and 7.5 % at pH 4. Although the concentration of pollutants decreased significantly, UV–VIS and TOC (total organic carbon) analyses showed the prevalent presence of intermediates during the degradation. During the degradation of benzoic acid, hydroxybenzoic acid (salicylic acid) was found by HPLC as an early intermediary product.

Multi-spectroscopic analysis and molecular simulations provide insights into the noncovalent interactions between the novel antimicrobial peptide Pup2 and Epigallocatechin-3-gallate (EGCG)

Antimicrobial peptide Pup2, due to high cost, shows restricted application value in food preservative, which may be improved by interacting with EGCG, characterized by good functional properties. This study aims to characterize a novel antimicrobial peptide-phenolic complex with activity against Staphylococcus aureus and investigate their interaction mechanism. Pup2 and Epigallocatechin-3-gallate (EGCG) exhibited synergistic effects, resulting in a 4-fold and 8-fold decrease in the minimum inhibitory concentration, respectively. Furthermore, the Pup2/EGCG showed a synergistic damaging effect on the bacterial cell wall and membranes. Multi-spectroscopic analyses, which included UV, fluorescence, FTIR, and Raman spectroscopy, showed that Pup2 and EGCG were non-covalently bound through hydrophobic interactions predominantly and assisted by hydrogen bonding. These interactions led to changes in the amino acid microenvironment of Pup2 and alterations in its secondary structure, with the α-helix content increasing from 3% to 26%. DSC similarly confirmed the occurrence of interactions and increased peptide stability. Additionally, molecular simulations further demonstrated hydrophobic interaction and hydrogen bonding were the main binding forces between Pup2 and EGCG, resulting in the formation of a stable complex. This study helps to elucidate the interaction mechanism between antimicrobial peptide Pup2 and EGCG at the molecular level, while highlights the potential application of this complex as a more economical and effective natural antimicrobial preservative.

A Combined LC-MS and Immunoassay Approach to Characterize Preservative-Induced Destabilization of Human Papillomavirus Virus-like Particles Adsorbed to an Aluminum-Salt Adjuvant.

During the multi-dose formulation development of recombinant vaccine candidates, protein antigens can be destabilized by antimicrobial preservatives (APs). The degradation mechanisms are often poorly understood since available analytical tools are limited due to low protein concentrations and the presence of adjuvants. In this work, we evaluate different analytical approaches to monitor the structural integrity of HPV16 VLPs adsorbed to Alhydrogel™ (AH) in the presence and absence of APs (i.e., destabilizing m-cresol, MC, or non-destabilizing chlorobutanol, CB) under accelerated conditions (pH 7.4, 50 °C). First, in vitro potency losses displayed only modest correlations with the results from two commonly used methods of protein analysis (SDS-PAGE, DSC). Next, results from two alternative analytical approaches provided a better understanding of physicochemical events occurring under these same conditions: (1) competitive ELISA immunoassays with a panel of mAbs against conformational and linear epitopes on HPV16 VLPs and (2) LC-MS peptide mapping to evaluate the accessibility/redox state of the 12 cysteine residues within each L1 protein comprising the HPV16 VLP (i.e., with 360 L1 proteins per VLP, there are 4320 Cys residues per VLP). These methods expand the limited analytical toolset currently available to characterize AH-adsorbed antigens and provide additional insights into the molecular mechanism(s) of AP-induced destabilization of vaccine antigens.

Association between parabens exposure and neurodevelopment in children

ObjectiveParabens are a group of substances commonly employed as antimicrobial preservatives. The effect of parabens on the development of neurotoxicity in children is still controversial. This study aimed to explore the associations between parabens exposure and children's neurodevelopmental performance, emphasizing potential sex differences and the combined effects of parabens. MethodsWe used the long-term follow-up study of Taiwanese generation, Taiwan Birth Panel Study II (TBPS II). We recruited the group of children at 6–8 years old. And, we measured parabens in children urine, including methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP). Children's attention-related performance was evaluated using the Conners Kiddie Continuous Performance Test 2nd Edition (K-CPT 2). The study employed both linear regression and mixture analysis quantile g-computation (QGC) methods to discern associations. A stratified analysis by sex and QGC was implemented to delve deeper into the cumulative effects of parabens. ResultsA total of 446 subjects completed both the parabens analysis and the K-CPT 2 survey. The overall association between parabens and neurodevelopmental performance was not pronounced, but discernible sex differences emerged. In the single pollutant analysis, elevated PP concentrations were associated with higher K-CPT 2 scores particularly in detectability (d') (β = 0.92 [95 % CI = 0.15 to 1.69]) and commissions (β = 0.95 [95 % CI = 0.12 to 1.78]), among girls. Further, in the mixture analysis, a significant association between PP and detectability (d') was observed in girls (β = 1.68 [95 % CI = 0.11 to 3.26]). ConclusionsThis study identified sex-specific associations between parabens and attention performance. Consistent outcomes across single and mixture analysis methods. Further research is crucial to clarify these causal associations.

Repeated-dose toxicity and toxicokinetic study of isobutylparaben in rats subcutaneously treated for 13weeks.

Parabens have historically served as antimicrobial preservatives in a range of consumables such as food, beverages, medications, and personal care products due to their broad-spectrum antibacterial and antifungal properties. Traditionally, these compounds were believed to exhibit low toxicity, causing minimal irritation, and possessing limited sensitization potential. However, recent evidence suggests that parabens might function as endocrine-disrupting chemicals (EDCs). Consequently, extensive research is underway to elucidate potential human health implications arising from exposure to these substances. Among these parabens, particular concerns have been raised regarding the potential adverse effects of iso-butylparaben (IBP). Studies have specifically highlighted its potential for inducing hormonal disruption, significant ocular damage, and allergic skin reactions. This study aimed to evaluate the prolonged systemic toxicity, semen quality, and estrus cycle in relation to endocrine disruption endpoints, alongside assessing the toxicokinetic behavior of IBP in Sprague-Dawley rats following a 13-week repeated subcutaneous administration. The rats were administered either the vehicle (4% Tween 80) or IBP at dosage levels of 2, 10, and 50mg/kg/day for 13weeks. Blood collection for toxicokinetic study was conducted on three specified days: day 1 (1st), day 30 (2nd), and day 91 (3rd). Systemic toxicity assessment and potential endocrine effects were based on various parameters including mortality rates, clinical signs, body weights, food and water consumption, ophthalmological findings, urinalysis, hematological and clinical biochemistry tests, organ weights, necropsy and histopathological findings, estrus cycle regularity, semen quality, and toxicokinetic behavior. The findings revealed that IBP induced local irritation at the injection site in males at doses ≥ 10mg/kg/day and in females at 50mg/kg/day; however, systemic toxicity was not observed. Consequently, the no-observed-adverse-effect level (NOAEL) for IBP was determined to be 50mg/kg/day in rats of both sexes, indicating no impact on the endocrine system. The toxicokinetics of IBP exhibited dose-dependent systemic exposure, reaching a maximum dose of 50mg/kg/day, and repeated administration over 13weeks showed no signs of accumulation.

A large-scale survey of urinary parabens and triclocarban in the Chinese population as well as the influencing factors and health risks

Parabens and triclocarban are widely applied as antimicrobial preservatives in foodstuffs, pharmaceuticals, cosmetics, and personal care products. However, few studies have been conducted on large-scale biomonitoring of parabens and triclocarban in the Chinese general population. In the present study, there were 1157 urine samples collected from 26 Chinese provincial capitals for parabens and triclocarban measurement to evaluate the exposure levels, spatial distribution, and influencing factors, as well as associated health risks in the Chinese population. The median concentrations of Σparabens and triclocarban were 14.0 and 0.03 μg/L, respectively. Methyl paraben was the predominant compound. Subjects in western China were more exposed to parabens, possibly due to climate differences resulting in higher consumption of personal care products. Subjects who were female, aged 18–44 years, or had a higher education level were found to have higher paraben concentrations. The frequency of drinking bottled water was positively associated with paraben exposure. The assessment of health risk based on urinary paraben concentrations indicated that 0.8 % of the subjects had a hazard index exceeding one unit, while Monte Carlo analysis suggested that 3.6 % of the Chinese population exposure to parabens had a potential non-carcinogenic risk. This large-scale biomonitoring study will help to understand the exposure levels of parabens and triclocarban in the Chinese general population and provide supporting information for government decision-making.

On Antimicrobial Preservatives in Soft Dosage Forms

On Antimicrobial Preservatives in Soft Dosage Forms

Phenolic compounds and antimicrobial activity of leaves of the genus Sorbus species and natural hybrids

The identification of new sources of biologically active substances is an actual direction of research in recent years, in particular, the demand for antimicrobial compounds and natural preservatives of plant origin is growing. Plants of the genus Sorbus L. are known in folk medicine, but for the rational use of plant material, there is a lack of systematic study of the features of the secondary metabolites’ accumulation and the spectrum of biological activity of plants during vegetation in different environmental conditions. In the present work, the seasonal dynamics of the total content of polyphenols, flavonoids and free phenolic acids in the leaves of rowan plants natural to the flora of Ukraine and introduced in the steppe region were investigated. The highest accumulation of phenolic compounds was found in the leaves of S. domestica, S. latifolia, S. hybrida, S. torminalis and S. aucuparia in the first half of June, and in S. aria and S. intermedia in May, which will serve as a criterion for selecting the best plant material to obtain biologically active compounds. The seasonal dynamics of the content of flavonoids and phenolic acids in the leaves of plants had significant species differences, which require more in-depth studies of the phytocompounds component composition. Antimicrobial activity of leaf ethanol extracts of rowan plant was found to be high against gram-negative bacterial strain Klebsiella pneumoniae B920 (especially the activity of S. aria, S. intermedia and S. aucuparia extracts) and Pseudomonas aeruginosa B907 (especially the activity S. torminalis and S. domestica), clinical gram-positive strains of Staphylococcus epidermidis (the highest activity of S. aria, S. domestica and S. intermedia extracts), as well as against clinical strains of fluconazole-resistant fungus Candida albicans (especially the activity of extracts of S. latifolia S. torminalis and S. intermedia). A conclusion was made about the prospects of using leaf extracts of the genus Sorbus plants as an economical and affordable natural source of biologically active polyphenols with a wide spectrum of antimicrobial activity. Further research may be aimed at elucidating the component composition of rowan leaf extracts and establishing the relationship between individual phytocompounds and the antimicrobial effects of plant extracts.

Cell structure damage contributes to antifungal activity of sodium propylparaben against Trichothecium roseum

Trichothecium roseum is a type of fungus that causes pink rot in muskmelon after the melons are harvested. Pink rot leads to severe decay during storage and causes the production of toxins that can be harmful to human health. Sodium propylparaben (SPP, IUPAC name: sodium; 4-propoxycarbonylphenolate) is an antimicrobial preservative that can be used to treat the inedible parts of fruits in addition to food, medications, and packaging. In this study, the effectiveness of SPP in inhibiting T. roseum was tested, and the inhibition mechanism was investigated. The results show that SPP inhibited the growth and spore germination of T. roseum. The malondialdehyde (MDA) content, propidium iodide staining, alkaline phosphatase (AKP) activity, and calcofluor white (CFW) staining results show that SPP produced a disruption of the cell membrane and cell wall integrity of T. roseum. Scanning and transmission electron microscopy (SEM and TEM, respectively) results also indicate that SPP disrupted the cellular structure of T. roseum. Meanwhile, the large amounts of superoxide anion and hydrogen peroxide in T. roseum accumulated due to the effects of SPP on the activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase, and decreased catalase. In addition, SPP caused a significant reduction in the incidence rate and disease degree of muskmelon pink rot in vivo. In conclusion, SPP appears to be effective against T. roseum via disruption of the cell membrane and wall. SPP could be used to manage melon pink rot after fruit harvesting because of its disease inhibition effect in vivo.

Analytical Methods and Regulative Viewpoint of Antimicrobial Preservatives in Cosmetics

Cosmetics need to be resistant to microbial contamination to protect consumer health and increase shelf life, much like any other product containing water, organic and inorganic components. The aims of anti-microbiological activity are to protect consumers from potentially harmful bacteria and to preserve products subject to degradation. Chemical, physical, or physicochemical methods are used to ensure this. Organic acid preservatives, alcohols, formaldehyde releasers, halogenated preservatives, isothiazolinones, quaternary ammonium salts and chlorhexidine are among the preservatives included in the legislation. Indeed, high quantitiesare more successful from a preservation standpoint, nevertheless they are toxic to consumers, whereas low amounts can lead to microbial resistance. Accordingly, the criteria of several international legislation and validation methods for introducing microbiologically safe items to the market have become essential. Although there are many approaches based on gas chromatography (GC) as per literature, the most common methods for the determination of preservatives are based on liquid chromatography (LC). Both of these procedures, as well as capillary electrophoresis (CE) and micellar electro kinetic chromatography (MEKC), have been frequently utilized in the cosmetics industry to determine preservative levels. Analytical approaches have been primarily focused on parabens, whereas the number of available methods to investigate other preservatives is limited. There is a tendency toward the usage of miniature extraction processes where new and improved sample preparation and extraction techniques including matrix solid-phase dispersion, solid-phase extraction, pressurized liquid extraction/supercritical fluid extraction and microextraction-based method have been introduced with high levels of efficiency and extraction capacities. Considering the significance and relevance of preservatives in cosmetics, this study highlights the most recent state-of-the-art information on their safety and regulatory concerns. Given the rising influence on consumer health, sample preparation and analytical methods forpreservative detection were also investigated which have been proposed by the international scientific literature.&#x0D; Keywords: Preservatives, Cosmetics, Analytical Techniques, Derivatization, Extraction

Interaction between preservatives and a monoclonal antibody in support of multidose formulation development

Multidose formulations have patient-centric advantages over single-dose formats. A major challenge in developing multidose formulations is the prevention of microbial growth that can potentially be introduced during multiple drawings. The incorporation of antimicrobial preservatives (APs) is a common approach to inhibit this microbial growth. Selection of the right preservative while maintaining drug product stability is often challenging. We explored the effects of three APs, 1.1 % (w/v) benzyl alcohol, 0.62 % (w/v) phenol, and 0.42 % (w/v) m-cresol, on a model immunoglobulin G1 monoclonal antibody, termed the “NIST mAb.” As measured by hydrogen exchange-mass spectrometry (HX-MS) and differential scanning calorimetry, conformational stability was decreased in the presence of APs. Specifically, flexibility (faster HX) was significantly increased in the CH2 domain (HC 238–255) across all APs. The addition of phenol caused the greatest conformational destabilization, followed by m-cresol and benzyl alcohol. Storage stability studies conducted by subvisible particle (SVP) analysis at 40 °C over 4 weeks further revealed an increase in SVPs in the presence of phenol and m-cresol but not in the presence of benzyl alcohol. However, as monitored by size exclusion chromatography, there was neither a significant change in the monomeric content nor an accumulation of soluble aggregate in the presence of APs.

Acetobacter pomorum in the Drosophila gut microbiota buffers against host metabolic impacts of dietary preservative formula and batch variation in dietary yeast.

Gut microbiota are fundamentally important for healthy function in animal hosts. Drosophila melanogaster is a powerful system for understanding host-microbiota interactions, with modulation of the microbiota inducing phenotypic changes that are conserved across animal taxa. Qualitative differences in diet, such as preservatives and dietary yeast batch variation, may affect fly health indirectly via microbiota, and may potentially have hitherto uncharacterized effects directly on the fly. These factors are rarely considered, controlled, and are not standardized among laboratories. Here, we show that the microbiota's impact on fly triacylglyceride (TAG) levels-a commonly-measured metabolic index-depends on both preservatives and yeast, and combinatorial interactions among the three variables. In studies of conventional, axenic, and gnotobiotic flies, we found that microbial impacts were apparent only on specific yeast-by-preservative conditions, with TAG levels determined by a tripartite interaction of the three experimental factors. When comparing axenic and conventional flies, we found that preservatives caused more variance in host TAG than microbiota status, and certain yeast-preservative combinations even reversed effects of microbiota on TAG. Preservatives had major effects in axenic flies, suggesting either direct effects on the fly or indirect effects via media. However, Acetobacter pomorum buffers the fly against this effect, despite the preservatives inhibiting growth, indicating that this bacterium benefits the host in the face of mutual environmental toxicity. Our results suggest that antimicrobial preservatives have major impacts on host TAG, and that microbiota modulates host TAG dependent on the combination of the dietary factors of preservative formula and yeast batch. IMPORTANCE Drosophila melanogaster is a premier model for microbiome science, which has greatly enhanced our understanding of the basic biology of host-microbe interactions. However, often overlooked factors such as dietary composition, including yeast batch variability and preservative formula, may confound data interpretation of experiments within the same lab and lead to different findings when comparing between labs. Our study supports this notion; we find that the microbiota does not alter host TAG levels independently. Rather, TAG is modulated by combinatorial effects of microbiota, yeast batch, and preservative formula. Specific preservatives increase TAG even in germ-free flies, showing that a commonplace procedure in fly husbandry alters metabolic physiology. This work serves as a cautionary tale that fly rearing methodology can mask or drive microbiota-dependent metabolic changes and also cause microbiota-independent changes.

Antibacterial Mechanism of Rhamnolipids against Bacillus cereus and Its Application in Fresh Wet Noodles.

Bacillus cereus (B. cereus) is a common foodborne pathogen causing food poisoning incidents. This study aimed to evaluate the antibacterial activity and underlying mechanism of rhamnolipids (RLs) against B. cereus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of RLs for B. cereus were determined to be 16.0 mg/L and 32.0 mg/L, respectively. Scanning electron microscopy and fluorescence microscope images, as well as data of membrane potential, relative electric conductivity, and leakage of intracellular components revealed that RLs disrupted the integrity of the cell membrane. Furthermore, the reactive oxygen species content, catalase (CAT) and superoxide dismutase (SOD) activity indicated that RLs activated the oxidative stress response of B. cereus in response to RLs. Fresh wet noodles (FWN) were used as a food model, and RLs showed a significant killing effect on B. cereus with a sustained inhibitory effect at the concentrations ranging from 128.0 to 1024.0 mg/kg. Additionally, RLs promoted the conversion of free water to bound water in FWN, which improved the storage of FWN and made the taste more resilient and chewy. These results suggest that RLs could be a potential alternative to antimicrobial agents and preservatives for applications in food processing.

Marine-Derived L-asparaginase as anti-Microbial and Food Preservative against Listeria monocytogenes isolated from Basa Fish Fillet (Pangasius bocourti)

Marine-Derived L-asparaginase as anti-Microbial and Food Preservative against Listeria monocytogenes isolated from Basa Fish Fillet (Pangasius bocourti)