Musty Odor Research Articles

Can beets beat mosquitoes?

If you’ve smelled the musty odor of moist soil or the air after a rainstorm, you’ve smelled geosmin, a terpene produced by soil bacteria and cyanobacteria (blue-green algae). Although scientists don’t know why humans have developed such a sensitivity for the scent, it seems some insects can also detect it. In Sweden, the US, and Brazil, researchers have now found that the yellow-fever mosquito Aedes aegypti is attracted to geosmin. The scientists demonstrated that the odorant could be useful in mosquito traps that help control the spread of disease (Curr. Biol. 2019, DOI: 10.1016/j.cub.2019.11.002). In 2012, Marcus C. Stensmyr of Lund University was part of a group that found that the common fruit fly Drosophila melanogaster sniffs out and avoids geosmin because the compound is produced by molds that make fruit unsuitable feeding and breeding sites (Cell 2012, DOI: 10.1016/j.cell.2012.09.046). Because of the group’s finding in fruit flies, Nadia Melo,

Prevalence and risk factors of pre-sick building syndrome: characteristics of indoor environmental and individual factors

BackgroundWith the aim to prevent sick building syndrome and worsening of allergic symptoms, primarily resulting from the indoor environment, the relationships among people’s residential environment in recent years, their lifestyle habits, their awareness, and their symptoms were investigated using an online survey.MethodsIn the survey, respondents experiencing symptoms specific to sick building syndrome, although they were not diagnosed with sick building syndrome, were categorized in the pre-sick building syndrome group. The relationships among individual characteristics, residential environment, and individual awareness were analyzed.ResultsResults showed that the prevalence of pre-sick building syndrome was high among young (aged 20–29 years) population of both sexes. In addition, “condensation,” “moisture,” “musty odors” in the house, and the “use of deodorant and fragrance” were all significantly associated with pre-sick building syndrome. Conversely, there was no significant association with recently built “wooden” houses that are highly airtight and have thermal insulation.ConclusionsEfficient “ventilation” plans and “ventilation” improvement and air conditioning systems to prevent mold and condensation in rooms are necessary to maintain a good, indoor environment that is beneficial for health. Efforts should also be made to encourage individuals to regularly clean and effectively ventilate their homes.

Characterization of the Key Aroma Compounds in Three Truffle Varieties from China by Flavoromics Approach.

The volatile compounds of three different fresh-picked truffle varieties (Tuber sinensis, T1, Tuber sinoalbidum, T2 and Tuber sinoexcavatum, T3) were extracted by headspace solid-phase microextraction (HS-SPME). Separation and identification of volatile components and sulfur compounds were investigated by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC–MS) and gas chromatography with flame photometric detection (GC-FPD). The results showed that 44, 43 and 44 volatile compounds were detected in T1, T2 and T3 samples, respectively. In addition, 9, 10 and 9 sulfur compounds were identified in three samples by GC-FPD, respectively. Combining physicochemical and sensory properties, T1 presented fatty, green and rotten cabbage odor; T2 exhibited mushroom, sulfuric and musty odor notes; T3 had nutty, floral and roasted potato odor. Dimethyl sulfide, 3-methylbutanal, dimethyl disulfide, 3-octanone, bis(methylthio) methane, octanal, 1-octen-3-one, 1-octen-3-ol and benzeneacetaldehyde played indispensable roles in the overall aroma of three truffles. Finally, based on quantitative concentration in T1, odorous compounds (OAV) > 1 were mixed to recombine aroma, demonstrating that these key aroma compounds based on OAV can successfully recombine pretty similar aroma of each variety.

Preparation of High-Quality Fermented Fish Product.

This protocol provides a method for preparation of industrialized fermented fish product with sturgeon (Aquilaria sinensis) meat product. The procedures were: (1) pretreatment of farmed sturgeon including decapitation, evisceration, skinning-off, cleaning and cutting; (2) marinating fish cubes in 6-12% (w/v) salt solution (1:1, fish cube mass to solution volume); (3) drying fish cubes to a water content of 50-60% by hot air (40-60 °C) or by vacuum; (4) fermentation involving inoculating fish cubes with 0.4-1.6% (w/w) S. cerevisiae in flavor solution to fish cubes and fermenting at 25-35 °C for 6-10 h; (5) sealing fish cubes in vacuum packages with marinating and fermenting solutions; (6) sterilizing at 115-121 °C for 10-20 min. The sturgeon meat product prepared by this method has delicious taste which is mellow and thick, has various types and large amounts of volatile flavor compounds such as alcohols and esters which could mask musty and unpleasant odor from fish, has moderate salt content but good texture properties such as high springiness, gumminess and chewiness, and has bright russet color and attractive appearance. This new technique could also be applied in the processing of other fish to provide convenient fish snack foods which could be stored at room temperature. It is appropriate for both marine and freshwater fish.

Treatment performance comparison between regular O3\u2013BAC and O3\u2013BAC with rear sand filtration: verification in a full-scale study

BackgroundTo improve the microbial safety of drinking water, an arrangement of O3–BAC with rear sand filtration (O3–BAC–sand) has been proposed. In this study, efforts were devoted to evaluate the benefits and drawbacks of O3–BAC–sand in a full-scale water treatment plant. The performance of the two configurations was compared in terms of particles, turbidity, CODMn and typical odorants and pesticides.ResultsThe O3–BAC–sand yielded lower turbidity but higher CODMn (by approximately 7%) in the finished water than regular O3–BAC (sand–O3–BAC). Both systems removed odors in raw water; however, sand–O3–BAC was more effective on septic and musty odorants. The total pesticide removals by sand–O3–BAC and O3–BAC–sand were 78% and 72%, respectively; though the latter had shorter activated carbon durable years.ConclusionThe re-location of the sand filter would sacrifice the BAC efficiency in removals of organic matter and micropollutants. This tradeoff is a result of the loss of the particulate organic matter removal by sand filters, because locating the sand filter behind BAC causes particle load increase on BAC; some measures of enhanced coagulation should be suggested to improve the turbidity and particle removal. The study will be helpful for improvement of the O3–BAC process in drinking water treatment.

Can PASS activity index be utilized around the world? Results from a multi-center, international, prospective cohort in acute pancreatitis

Phenylketonuria (PKU) arises from a mutation in the phenylalanine hydroxylase (PAH) gene. It is recessive and must be transmitted to the child from both parents to have an effect. A child who is homozygous for the mutation shows several phenotypic changes (gene pleiotropy), including severe retardation of mental development, urine that turns green in a solution of iron chloride, a musty odor, and many signs of protein malnutrition. The gene is expressed in the liver, not the brain. A defective enzyme is unable to convert the amino acid phenylalanine into tyrosine, and the resulting high levels of phenylalanine in the blood damage the infant's brain. The disorder can be detected with newborn screening and treated effectively by rearing the infant on an artificial diet low in phenylalanine. Keeping to the diet is difficult because of social pressures. Although PKU is a single-gene disorder, it is rather complex.

Utilization of mocaf flour (modified cassava flour) for revitalization of the use tapioca flour in communities for empowering hulu-hilir human resources in wonogiri regency

Mocaf flour is a flour made from cassava or cassava which is modified by using microbial fermentation techniques. Mocaf flour has characteristics that are good enough to substitute or replace 100% use of wheat flour. Compared with unfermented cassava flour or cassava flour, mocaf flour has a better quality, which is whiter and the cassava aroma is lost. In cassava flour products without fermentation or cassava, the color is less white (blackish brown) and often musty odor is very strong so that when applied to the product, the performance of the product is less attractive and there is still a distinctive aroma of cassava. This often makes the food processing industry which is made from cassava or cassava flour becomes less satisfied. The findings of modified cassava flour (mocaf) in which the characteristics of mocaf flour are whiter and the aroma of cassava has been lost so that substituting flour does not reduce the quality of the product if the proportion of its use is in accordance with the type of product.

National survey of utilization of continuous water quality monitors in water supply systems in Japan

Abstract An investigation of the utilization of water quality monitors at water purification plants throughout Japan was conducted via questionnaire from August to October 2015. The number of types of monitors installed at more than one water purification plant was 34. Chlorine, high sensitivity turbidity, pH, and turbidity monitors were (highly) recommended for installation in four water purification processes (rapid sand filtration, chlorination only, slow sand filtration and membrane treatment), except for high sensitivity turbidity of chlorination only. The number of installations of the monitors recommended and their installation points were dependent upon the processes. Highly recommended points of turbidity were raw water and sedimentation points, which were set for (critical) control points in water safety plans. That of high sensitivity turbidity was the rapid sand filtration point for confirmation of Cryptosporidium control. Chlorine monitors were applied for automatic control, regardless of the water purification processes. Some interesting monitors, such as those for musty odor compounds and trihalomethane, were newly developed and utilized. The results of this study showed that water quality monitors were important for water quality management systems based on water safety plans in Japan.

Increased electrode activity during geosmin oxidation provided by Pt nanoparticle-embedded nanocarbon film.

The musty odor compound geosmin was electrochemically detected by using Pt nanoparticle (PtNP)-embedded nanocarbon (Pt-C) films formed with unbalanced magnetron (UBM) co-sputtering. The sputtered Pt components formed NPs (typically 1.53-4.75 nm in diameter) spontaneously in the carbon films, owing to the poor intermiscibility of Pt with carbon. The surface concentrations of PtNPs embedded in the nanocarbon film were widely controllable (Pt = 4.8-35.9 at%) by regulating the target powers of the Pt and carbon individually. The obtained film had a flat surface (Ra = 0.17-0.18 nm) despite the fact the PtNPs were partially exposed at the surface. Compared with a Pt film electrode, some Pt-C films exhibited higher electrode activity against geosmin although the surface Pt concentrations of these Pt-C films were much lower than that of the Pt film electrode, thanks to the wider potential window and lower background current that resulted from the ultraflat and stable carbon-based film prepared by UBM co-sputtering. Computational experiments revealed that the theoretical oxidation potential (Eox) value for geosmin was relatively similar to that obtained in electrochemical experiments using our Pt-C film electrode. Moreover, we also theoretically estimated the possible oxidation site of geosmin molecules and the advantage of the NP shape of the electroactive Pt parts as regards the electrochemical oxidation of geosmin. We successfully used the Pt-C film (10.6 at%) electrode to detect geosmin in combination with HPLC at a low detection limit of 100 ng L-1.

Synergistic effect of musty odorants on septic odor: Verification in Huangpu River source water

Revealing the main contributors to septic odor is a challenge since diverse compounds are responsible for this odor, and there might exist synergistic effects among different odorants. In this study, based on a reconstitution evaluation, the contribution of eighteen odorants identified in Huangpu River source water to the septic odor was explored. The reconstitution test result showed that the three typical odorants, including bis(2‑chloroisopropyl) ether (BCIE), diethyl disulfide (DEDS) and dimethyl disulfide (DMDS), with respective average odor activity values (OAVs) of 2.35, 1.65 and 0.78, only contributed 61 ± 3% of the FPA intensity for septic odor in Huangpu source water. At a BCIE concentration of 50 ng/L, synergistic effect for the septic odor occurred at 10 ng/L for geosmin and 20 ng/L for 2‑methylisoborneol (MIB), showing that coexisting musty odorants could enhance the septic odor intensity caused by some typical odorants. When both geosmin and MIB, with an average OAV of 4.54 and 1.38, were further included in addition to the three typical odorants, 88 ± 4% of the septic odor in Huangpu River source water could be explained. With addition of the remaining odorants with much lower OAVs (<0.23), 94 ± 2% of the septic odor could be explained. The musty odor was not affected by the presence of the co-existing odorants at the concentration levels of the present study. This study indicated that the overall odor of water contaminated with musty and septic odorants is a combination of both concentrations of individual contaminants and their synergistic effects. This is the first study to reveal the synergistic effects of typical musty odorants on septic odor, and the results of this study demonstrated that the synergistic effects of other odorants should be considered when dealing with the septic odor in drinking water.

Characterization of 3-Methylindole as a Source of a "Mud"-like Off-Odor in Strong-Aroma Types of Base Baijiu.

The "mud"-like off-odor, which is an odor reminiscent of musty and strong animal fecal odors, affects the quality classification of the strong-aroma types of baijiu (SAB), but little is known about which compounds are responsible for this aroma, except for certain phenolic compounds. However, not all mud-like off-odor expressions in SAB can be attributed to those phenolic compounds. In this work, volatile compounds in pit mud and SAB samples were isolated by headspace solid-phase microextraction and liquid-liquid extraction. An odoriferous zone was detected by GC-MS/olfactometer and GC-MS and was attributed to 3-methylindole rather than ethyl oleate on the basis of their odor characteristics, MS data, and retention indices. Combined with the detection threshold of 3-methylindole determined by a three-alternative forced-choice (6.09 μg/L) procedure, odor activity values in the tested base SAB were from 1 to 23. Sensory studies and the prepared heat map highlighted the contribution of this compound to the odor characteristics for the first time.

Association Between SSR Molecular Markers and Chemical and Sensory Traits of Cacao Samples Using Multiple Regression Analysis.

The sensory properties of cacao beans are linked to the chemical composition of the seeds, and both characteristics are the partial results of its allelic composition. Therefore, it is useful to search for molecular markers associated with these traits. We perform multiple regression analysis to associate previously generated data of alleles generated with 12 SSR (of cultivated cacao trees) with data obtained from chemical and sensory characterization (of beans) of plants grown in the southern region from Mexico. When the association was significant, the mathematical models for predictive purposes were proposed. All phenotypic traits evaluated showed equations with setting values R2 > 0.5. All chemical characters tested have a significant association with at least two alleles (P < 0.05). In addition, the fat content was associated with six molecular markers (mTcCIR03209, mTcCIR12188, mTcCIR19286, mTcCIR07150, mTcCIR19310). The most common allele was mTcCIR12188, which was associated with the contents of eicosanoic acid, moisture, fat and total polyphenols content. The mTcCIR28362 allele is associated with sensory characters bitterness, musty odor, and roasted odor. These alleles could be useful as molecular markers of chemical and sensory characteristics of cacao samples.

Application of post-column reaction GC for accurate and direct determination of musty odor substances in standard solution

By using post-column reaction GC, a method for accurate and direct characterization of musty odor substances (2-methylisoborneol and geosmin) in a candidate standard solution has been developed. Because the GC system gives a response depending on the number of carbon atoms constituting the organic compound by combustion and conversion to methane, naphthalene and diethyl phthalate, purity of which had been accurately assessed, were used as reference materials for calibration. To verify the method, concentrations of 2-methylisoborneol and geosmin in the sample determined by the method were compared with the concentrations calculated based on gravimetric mixing that is one of the general methods for the characterization of the organic standard solutions. The analytical results of each analyte obtained by the two methods agreed within a deviation of about 0.5 % or less.

Musty and earthy odor compounds including 2,4,6-trichloroanisole in treated wastewater

Musty and earthy odor compounds including 2,4,6-trichloroanisole in treated wastewater

Two new Pseudanabaena (Cyanobacteria, Synechococcales) species from Japan, Pseudanabaenacinerea and Pseudanabaena yagii, which produce 2‐methylisoborneol

SUMMARYTwo new Pseudanabaena species, Pseudanabaena cinerea and Pseudanabaena yagii, were described. Both species are members of taxa that produce 2‐methylisoborneol and have a musty odor. P. cinerea was found at the Serikawa reservoir and in Lake Ogawara in Japan. P. cinerea is morphologically similar to P. subfoetida Niiyama et Tuji, but its cell color is different. The cell color of the former is greenish‐gray to gray, and that of the latter is bright blue‐green. P. yagii was described using an old strain, NIVA‐CYA 111, which was isolated from Lake Biwa in 1982. P. yagii can be distinguished from other 2‐MIB‐producing taxa by its thinner cell width and by the absence of small granules in its cells. The putative secondary structures of the internal transcribed spacer (ITS) regions of the ribosomal RNA operon were predicted for 2‐MIB‐producing Pseudanabaena species including the two new taxa. Both new taxa are also distinguished by their molecular phylogenies using 16S rRNA and rbcL, and by the secondary structures of the ITS regions of the rRNA operon.

A challenge to detect musty odor of water using insect olfactory receptors

A challenge to detect musty odor of water using insect olfactory receptors

Behavior and Countermeasures of Musty Odor Producing Cyanobacteria on the Riverbed～A study on upstream of Tama river～

Behavior and Countermeasures of Musty Odor Producing Cyanobacteria on the Riverbed～A study on upstream of Tama river～

Identification of Musty Odor Nuisance at Wastewater Treatment Plants

Identification of Musty Odor Nuisance at Wastewater Treatment Plants

The scientists who sniff water

Mel Suffet stood at a whiteboard, dry-erase marker in hand, and asked me sarcastically, “Did you have fish for dinner?” He wasn’t commenting on my breath. For the past hour, I’d been sitting in a mini-cubicle, taking part in a six-person odor-sniffing panel in his lab at the University of California, Los Angeles. I’d just told him that a water sample I’d sniffed had a musty and fishy odor. “I’m not going to put it down because it’s wrong,” he said. “We don’t have a fishy odor.” He paused from recording the other panelists’ descriptions, went to a fume hood, and pulled out the Erlenmeyer flask containing the sample in question. He told me to smell it again. After a few sniffs, I realized he was right: It was musty and pine scented. Clearly, smelling water is challenging. The exercise was an example of how water scientists analyze funky-smelling water.

Geosmin-producing Species of Coelosphaerium (Synechococcales, Cyanobacteria) in Lake Shinji, Japan

In Lake Shinji, Japan, periodic outbreaks of musty odour have occurred since mid-May 2007. Although the substance responsible for the odour was identified as geosmin, the odour-producing organism was unknown. We cultivated an axenic unialgal strain and determined that a species of Coelosphaerium (Synechococcales) was responsible for the production of geosmin in Lake Shinji. Our analysis was conducted using gas chromatography/mass spectrometry to determine the odorous compound. To determine the algae species, it was observed by optical microscopy to describe its morphological characteristics and the polymerase chain reaction was used to characterise the nucleotide sequence of the 16S rRNA gene and the 16S-23S rRNA internal transcribed spacer region. In addition, we explored the relationship between the number of cells of the Coelosphaerium sp. and the concentration of geosmin. In conclusion, geosmin, the cause of the musty odour in Lake Shinji in autumn 2009, was produced by Coelosphaerium sp., and to our knowledge, this is the first report of a geosmin-producing species in the family Coelosphaeriaceae.