Amino acids in yeast fermentation: A review of their roles from nutrients to modulators.

Electrode potentials influence the generation and fate of volatile sulfur compounds from sludge anaerobic digestion via microbial extracellular electron transfer.

This study assessed the feasibility of remote halitosis diagnosis by evaluating VSC stability over 7 days and their association with periodontal parameters. One hundred adult patients attending a periodontal examination were included. Oral gas samples were collected using plastic syringes and analyzed by gas chromatography (OralChroma) at baseline (D0) and after 7 days of storage at room temperature (D7). Hydrogen sulfide (H2S), methyl mercaptan (CH3SH), and dimethyl sulfide ((CH3)2S) were quantified. Periodontal parameters were recorded. Correlations and agreement analyses were performed. At D0, 64% and 31% of patients were classified as having halitosis using thresholds of > 120 ppb and > 300 ppb, respectively. Mean VSC concentrations were 10.2 (33.1) ppb for H2S, 208.3 (443.2) ppb for CH3SH, and 79 (166) ppb for (CH3)2S, and increased after 7 days of storage for all compounds except H2S. Only (CH3)2S showed a significant correlation between D0 and D7 measurements. Agreement between halitosis diagnoses at D0 and D7 was poor for both thresholds (Cohen's kappa < 0.2). Associations between VSC levels and periodontal parameters were weak. Delayed analysis of oral gas samples significantly altered VSC measurements limiting their reliability for remote halitosis diagnosis. Periodontal parameters were not strongly associated with VSC levels.

Organic sulfur metabolism drives volatile sulfur compound generation during wastewater treatment plant sludge thickening.

From multiphase redistribution to emission control: deciphering iron-mediated interactions in sulfur dynamics during sludge anaerobic digestion.

Periodontal disease (PD) is one of the most common infectious conditions in dogs, associated with plaque accumulation, gingival inflammation, halitosis, and tooth loss. Halitosis is primarily caused by volatile sulfur compounds (VSCs) generated by anaerobic bacteria, including Porphyromonas gulae (P. gulae), a pathogen closely linked to PD progression. This study examined the effects of oral interferon alpha (IFN-α) on halitosis and bacterial activity in dogs with PD. Thirty-two dogs with moderate-to-severe PD were enrolled and allocated to untreated controls (n = 10) or IFN-α treatment (n = 22). Dogs in the treatment group received 2.75 g of IFN-α formulation (InterBerryα®) applied to the gingival margin twice weekly for five weeks. Clinical outcomes included PD Severity Index, enzymatic activity to hydrolyze N-benzoyl-DL-arginine-naphthylamide (BANA), PCR detection of P. gulae, and halitosis evaluation by gas chromatography and pet owner assessment. IFN-α significantly reduced PD Severity Index, BANA activity, and VSC concentrations (hydrogen sulfide and methyl mercaptan) compared with baseline and controls. Additionally, 27% of treated dogs converted to P. gulae-negative status after therapy. Owners reported marked improvement in oral malodor. These findings suggest that oral IFN-α effectively alleviates halitosis and reduces periodontal pathogen activity, supporting its potential as a non-invasive treatment for canine PD.

How volatile sulfur compounds reshape soybean protein: From multiscale molecular binding mechanism study to emulsion system design

Halitosis in companion animals lacks safe, effective long-term solutions. This study evaluated sugar cane polyphenols (SP) as an oral deodorizer for dogs using acute and 30 day intervention trials. Efficacy was evaluated by sensory scoring, volatile profiling, microbiome analysis, and mechanistic assays. Oral malodor was significantly reduced in both the acute (0-120 min) spray test and the 30 day SP intervention, accompanied by decreases in volatile sulfur compounds and indole. Mechanistic evidence indicated that SP interacts with odorants through noncovalent interactions and reduces protein surface hydrophobicity. Molecular simulations further supported competitive occupation of hydrophobic and aromatic protein binding regions by SP. Meanwhile, salivary β-glucosidase activity was inhibited in a concentration-dependent manner. SP exposure was also associated with reduced abundances of odor-associated oral taxa, such as Porphyromonas and Fusobacterium. These findings support SP as a food-grade strategy for controlling canine halitosis, with translational relevance to oral care applications.

Black stain (BS) is a frequently observed condition in children and often leads to dental visits due to aesthetic concerns. Despite its association with the risk of caries, comprehensive data on the oral and dental health of children with BS, including the presence of caries, gingival health status, salivary parameters, the presence of halitosis, and nutritional status, are limited. Therefore, this study aimed to evaluate and compare the oral-dental health statuses of children with and without BS. The cross-sectional study evaluated demographic findings, oral hygiene habits, oral-dental health status, presence of halitosis, and nutritional characteristics. Oral-dental health status was evaluated using the decayed-missing-filled indices (dmft-dmfs-DMFT-DMFS), ICDAS-II index, pufa/PUFA index, plaque index (PI), and gingival index (GI). The presence of halitosis was determined by sulfur monitoring. Salivary pH, salivary buffering capacity, and salivary flow rate were also assessed. Nutritional characteristics were determined using a 3-day food record and a food frequency questionnaire. Statistical analyses were performed using the independent samples t-test, Mann-Whitney U test, and Fisher's exact test. Statistical significance was considered at the 5% level for the results of all analyses. In addition to p-values, effect sizes were calculated to assess the magnitude of differences between groups. From a total of 1720 patients initially assessed for study inclusion, and BS was observed in 69 patients (4.01%). 23 children with BS (study group) and 27 children without BS (control group), aged 6-13 years, were included in this study. The mean dmft-dmfs-DMFT-DMFS scores were 2.6 ± 2.7, 6.2 ± 7.3, 2.6 ± 2.5, and 2.7 ± 2.4 for children with BS and 3.4 ± 4.1, 9.8 ± 11.6, 4.1 ± 3.1, and 5.4 ± 5 for children without BS, respectively. In the BS group, the level of cavitated caries lesions in permanent teeth, the mean DMFS score, the mean PI score, and mean salivary pH and salivary buffering capacity were significantly higher (p ≤ 0.05 for all). No statistically significant differences were observed between the groups in other evaluated parameters, including volatile sulfur compound levels (p > 0.05). In the BS group, the mean intake of molasses, a food rich in iron, was significantly higher (p ≤ 0.05). Given the relatively small sample size, the generalizability of the findings is limited. Children with BS have lower rates of dental caries. Low caries levels in children with BS may be related to their low PI values, high salivary pH, and high salivary buffering capacity.

Background:This study evaluated the immediate effectiveness of a multi-channeled oral irrigator (MCOI) in removing dental plaque and reducing oral malodor.Methods:In 20 healthy volunteers, changes in dental plaque were assessed using the Patient Hygiene Performance index. Volatile sulfur compounds were measured before and immediately after a single use of the MCOI. Participants refrained from tooth brushing for 24 hours prior to the assessment. The device administered 1000 mL of water over a 1.5-minute cycle. Oral malodor was analyzed with gas chromatography focusing on methyl mercaptan (CH₃SH) and hydrogen sulfide. Statistical analysis was performed using the Wilcoxon signed-rank test and chi-square test.Results:After a cycle of MCOI use, the average and divisions of the tooth Patient Hygiene Performance index scores significantly decreased (P < .001), with an average reduction of 24.76% in initial dental plaque. Additionally, total volatile sulfur compounds and CH₃SH concentrations significantly decreased (P = .011) after oral cleaning. Although the mean hydrogen sulfide concentrations decreased after oral cleaning, this change was not statistically significant (P = .088).Conclusions:Tooth brushing typically removes approximately 42% to 60% of the initial dental plaque in healthy adults. A single cycle of MCOI use reduced plaque by approximately 25% and significantly lowered CH₃SH, a compound associated with periodontal disease. These findings suggest that the MCOI may serve as a useful adjunct to tooth brushing, particularly for individuals with limited motor skills, and could help reduce the risk of plaque-related oral diseases.

Halitosis, or oral malodor, is caused by unwanted oral microbes that metabolize proteins and produce volatile sulfur compounds (VSCs). These malodorous VSCs may negatively impact oral health as they are pro-inflammatory, and halitosis is generally considered an important marker of oral health status. A previous clinical study with 24 dogs showed that daily administration of 250 mg of a novel canine oral health postbiotic (COHP) significantly decreased VSCs by 26% compared to placebo on Day 14, with twice as many dogs showing perceptibly improved breath in the COHP group on Day 7. The present double-blinded, placebo-controlled validation study evaluated COHP's ability to reduce canine oral malodor at a reduced dose of 150 mg to confirm that the previously reported efficacy of COHP is reproducible and maintained at a lower dose. Twenty-four dogs were stratified by starting VSC levels and received either COHP or placebo as a powder topper over standard chow for 14 days. VSC levels were measured via a halimeter, and perceived malodor was assessed using a 10-point scale on Days 0, 7, and 14. VSC levels increased in the placebo group by 24% on Day 7 (P = .006) and 38% on Day 14 (P = .002), while COHP prevented VSC increases on both days, resulting in a -26% change compared to placebo on Day 14 (P = .04). VSC levels correlated with perceived malodor, and COHP trended toward a 1-point reduction in perceived malodor compared to placebo (P = .06). These findings agree with the previous study, suggesting COHP effectively reduces canine halitosis across 2 doses.

Background/Objectives: This study evaluated the effectiveness of Cotinus coggygria (Smoke Tree) Flower Water mouthwash in reducing halitosis and improving oral hygiene parameters among adolescents undergoing fixed orthodontic treatment. Methods: A double-blind, randomized, placebo-controlled, parallel-group clinical trial was conducted with 30 individuals undergoing treatment with fixed orthodontic appliances. Participants were allocated (1:1) into two groups: Group A received the Cotinus coggygria mouthwash, while Group B received the placebo mouthwash. Hydrogen sulfide (H2S) concentration in breath, measured by the OralChromaTM II device, was the primary outcome. Secondary outcomes included dimethyl sulfide [(CH3)2S] and methyl mercaptan (CH3SH) levels, assessed with the same device, and oral hygiene status evaluated using the Modified Silness & Löe Plaque (PI-M) as well as the Silness & Löe Gingival (GI) indices. Normality of the data distribution was assessed using the Shapiro–Wilk test. Statistical analyses were conducted using the Mann–Whitney U test and Student’s t-test. Results: A statistically significant reduction in H2S levels was observed in the C. coggygria group compared to placebo (p = 0.014). Median H2S levels decreased from 147.00 ppb at baseline (T0) to 35.00 ppb at follow-up (T1) after 2 weeks. A statistically significant reduction in total VSC levels was also observed in the C. coggygria group compared to placebo (p < 0.001). Median total VSC levels decreased from 254.00 ppb at baseline (T0) to 105.00 ppb at follow-up (T1) after 2 weeks. No significant differences were found between groups for the other volatile sulfur compounds. A Significant improvements were noted in periodontal parameters in favor of the C. coggygria group. The Gingival Index decreased from 2.0 to 1.3 (p < 0.001; 95% CI: −0.7 to −0.2), and the Plaque Index (PI-M) decreased from 1.6 to 1.0 (p = 0.001; 95% CI: −0.7 to −0.3). Conclusions: Cotinus coggygria mouthwash appeared to be an effective adjunct for managing halitosis and improving oral hygiene parameters in adolescents undergoing fixed orthodontic treatment. No adverse effects were reported.

Ostreopsis blooms promote production of volatile organic sulfur compounds: environmental and health implications.

Synergistic removal of methanethiol and other odorant gases by a metabolically complementary synthetic consortia isolated from food waste.

Volatile sulfur compounds belong to the group of odor active compounds with very low sensory threshold levels and can influence the aroma of various products either in a positive or a negative way. Due to their high odor potency and their low sensory thresholds, it is critical to identify these substances in complex food matrices. A new instrumental setup based on the combination of a two-dimensional comprehensive gas chromatographic system with simultaneous dual detection based on a sulfur chemiluminescence detector and a time-of-flight mass spectrometer separation and identification was tested. Additionally, two different column configurations were tested and compared for further optimization of separation and selectivity. Three different roasted coffee samples were used to demonstrate the potential of this new instrumental configuration, keeping in mind the volatile and odor active fraction of roasted coffee being among one of the most complex volatile composition when comparing to other food and beverage products.

Background and Objectives: Halitosis is a common condition with substantial psychosocial impact, frequently driven by intra-oral biofilm, tongue coating, and reduced salivary clearance. This study compared the short-term effectiveness of standardized counseling alone, probiotic lozenges containing Streptococcus salivarius K12, and a zinc-containing mouthrinse in adults with persistent intra-oral halitosis. Materials and Methods: In this 4-week, parallel-group, randomized pragmatic trial, 117 adults with bothersome halitosis for at least 3 months and baseline organoleptic score ≥ 2 were allocated 1:1:1 to standard care, probiotic lozenges, or zinc mouthrinse. All participants received standardized counseling and tongue cleaning instructions. The primary endpoint was change in volatile sulfur compounds (VSCs) measured by portable sulfide monitoring. Secondary outcomes included organoleptic score, Halitosis Associated Life-Quality Test (HALT), Oral Health Impact Profile-14 (OHIP-14), tongue coating, plaque, and salivary Solobacterium moorei quantified by qPCR. Results: Baseline demographic, clinical, and biochemical characteristics were comparable across groups. All interventions improved outcomes over 4 weeks, but improvements followed a consistent gradient favoring zinc mouthrinse, followed by probiotic lozenges, then standard care. Mean VSC reduction was −12.7 ± 33.9 ppb with standard care, −47.3 ± 42.2 ppb with probiotics, and −78.5 ± 36.3 ppb with zinc mouthrinse (p < 0.001). Organoleptic scores improved by −0.2 ± 0.7, −0.8 ± 0.8, and −1.2 ± 0.8, respectively (p < 0.001). HALT and OHIP-14 scores showed parallel reductions, and moderate/severe halitosis at week 4 remained most frequent in the standard care group (58.9%) and least frequent in the zinc group (20.5%; p = 0.004). Conclusions: Both active adjunctive strategies improved intra-oral halitosis beyond standardized counseling alone, but the zinc-containing mouthrinse produced the greatest short-term benefits across objective, clinician-rated, and patient-reported outcomes. These findings support zinc-based rinses as a practical short-term adjunct for managing persistent intra-oral halitosis in outpatient dental care. Durability after discontinuation and potential relapse beyond 4 weeks were not assessed in this trial.

This work shows the measurement of trace of odor-active compounds in air sampler collect from channeled emissions of Asphalt Mixture Plants by Nalophan bags, including formaldehyde, hydrocarbons, and volatile sulfur compounds by thermal desorption-gas chromatography-mass spectrometry (MS) equipped with an automated, three-stage preconcentration and water-management mechanism without liquid cryogen thanks to a dedicated focusing traps. The success of this application has benefited from computational workflow in Non-Targeted Analysis, applied to the complex raw MS data to obtain qualitative and quantitative matrix information through deconvolution by MassHunter Unknowns Analysis software. Deconvolution is one of the most challenging steps in GC-MS data processing reconstructing a pure mass spectrum for each component, permitting the identification of co-eluted volatile organic compounds (VOCs) by both matching the electronic ionization (EI) mass spectra and the Linear Temperature-Programmed Retention Index with reference values provided by spectral library. The described approach permitted a semi-untargeted screening of VOCs in complex matrix by single quadrupole-MS. Several oxygenated VOCs were found with relatively low abundances under the unresolved complex mixtures produced by co-elution in the range between heptane and dodecane. Samples collected in typical asphalt production conditions produced between 2000 and 4500 deconvolution results, with 300 to 500 library hits considering a minimum match factor of 70/100. Very VOCs resulted chromatographically resolved, while early eluting peaks were qualified by standard injection and single-ion monitoring acquisition, since EI spectra of such light molecules are characterized by an insufficient number of peaks to achieve a deconvolution under the predominant early elution of carbon dioxide.

Iron is a limiting micronutrient in various environments, and its scarcity orchestrates microbial interactions across diverse ecosystems. The cheese surface, which is oxic, iron-limited, and a host of moderately complex ecosystems, can serve as a model system to study iron-mediated microbial interactions. In this work, we focused on two ripening bacteria isolated from cheese, Hafnia alvei and Brevibacterium aurantiacum. We combine growth measurements, transcriptomics, proteomics, and metabolomics to examine the role of iron in their interactions within a synthetic medium designed to mimic late cheese ripening conditions, using mono and coculture systems under iron limitation. Coculturing resulted in significant differences in the physiology of both strains, with a more notable effect on H. alvei. H. alvei, the only siderophore producer of the two, appeared to experience iron limitation in the coculture. This is partially attributed to sharing siderophores, and thus, iron, with B. aurantiacum. Multi-omics analysis points to several key exchanges. First, putrescine acts as a cross-fed metabolite, where B. aurantiacum synthesizes it and H. alvei uses it as an energy source. Next, we found evidence for the activity of quorum sensing and potential quorum quenching mechanisms, previously implicated in siderophore biosynthesis. Additionally, coculturing led to increased production of volatile sulfur compounds, contributing to positive organoleptic characteristics of cheese. Our model system reveals the modifications of C, N, S metabolisms in response to an abiotic stress and provides a framework to study such responses in numerous iron-limited ecosystems.

Local halitosis affects a substantial proportion of adults and is predominantly of intraoral origin. Volatile sulfur compounds, principally hydrogen sulfide and methyl mercaptan, are generated by anaerobic bacteria acting on sulfur-containing amino acids within periodontal pockets and tongue biofilms. Periodontal disease, tongue coating, reduced salivary flow, carious lesions, and prosthetic factors are the main local contributors. This review provides dental clinicians with a concise, evidence-based overview of the etiological factors and their underlying mechanisms.

The oral microbiome is an important aspect of overall oral health in dogs. To investigate the ability of a postbiotic, canine oral health postbiotic (COHP), to support oral health, a double-blind, placebo-controlled study was conducted with a dirty tooth model to assess its ability to reduce volatile sulfur compound (VSC) producing microbes that cause halitosis and modulate canine oral microbiome composition. Ten client-owned dogs were randomly split into 2 groups. The groups received either the COHP or a placebo as a powder topper on food for 7 days. Oral microbiome samples were collected on day 0 and day 7 along with the buccal gingival margin. Hydrogen sulfide (H2S)-producing colonies were quantified by plating the oral microbiome samples and counting pigment-producing colonies. Additionally, oral microbiome samples were sequenced, and taxa abundance was quantified. A trend toward a reduction in H2S-producing colonies was observed in the COHP group (P = .06), but not in the placebo group (P = .9). Canine oral health postbiotic reduced the abundance of 9 times as many taxa as the placebo, including taxa that form biofilms and produce VSCs. The placebo reduced the abundance of only one taxon, which is not associated with biofilms or VSCs. The findings provide evidence for COHP's ability to promote a positive shift in the canine oral microbiome, and, together with previous results, provides evidence that it may broadly help to maintain canine oral health.