Search Results (7)

This study investigated the efficacy of heated scallop shell powder (HSSP) treatment in preserving chicken thigh meat. Chicken thigh meat was treated with HSSP slurry (1% and 5%) for 60 min, and the variation in aerobic bacteria and coliform populations was assessed during refrigerated storage (10 °C). There was a substantial increase in aerobic bacteria, reaching nearly 7 log₁₀ colony forming unit (CFU)/g following 7 days of refrigeration, in the untreated chicken meat. Conversely, the aerobic bacterial population of the HSSP-treated chicken was <5 log₁₀ CFU/g. Coliform growth in the untreated chicken reached over 5 log₁₀ CFU/g following 7 days. In contrast, the coliform population of the HSSP-treated chicken did not reach 5 log₁₀ CFU/g at 1% HSSP concentration; it was suppressed to <4 log₁₀ CFU/g at 5% concentration. Listeria monocytogenes, which can grow at low temperatures, was inoculated into the chicken meat (5 log₁₀ CFU/g) treated with alcohol, which was followed by HSSP. In the untreated chicken, L. monocytogenes increased to 9 log₁₀ CFU/g even when refrigerated for 7 days. However, in the chicken treated with 5% HSSP, L. monocytogenes was suppressed to approximately 3 log₁₀ CFU/g. These findings reveal that HSSP treatment is an effective method for disinfecting meat, inhibiting bacterial growth, and enhancing preservation. Full article

The main component of seashells is calcium carbonate (CaCO₃). When seashells are calcined at high temperatures, CaCO₃ becomes calcium oxide (CaO), and this CaO exhibits antimicrobial activity. In this study, we attempted to develop a transparent coating that retains antimicrobial activity for a long time by mixing polyvinyl butyral (PVB), which has excellent adhesive and binding properties, with heated shell powder (HSP). The scallop HSPs used in this study were nanoparticles with a particle diameter of approximately several hundred nm, and the prepared paint showed high transparency. Elemental analysis showed that scallop HSP particles existed in the paint as Ca(OH)₂. The antimicrobial activity of the surface applied with scallop HSP-containing PVB (HSSP-PVB) paint was then evaluated using JIS Z 2801 and ISO 21702: 2019. The HSSP-PVB paint-applied surfaces showed high antibacterial and antiviral activity. The antimicrobial activity of the scallop HSP-PVB paint-applied surface was attributed to the creation of a strongly alkaline environment due to surface hydration, and the strongly alkaline environment was maintained for a long period of time. It was suggested that the PVB covered the surface of the scalloped HSP particles, which significantly prevented the HSP from contacting CO₂ and H₂O molecules in the air. Full article

Methods to reuse large numbers of scallop shells from the harvesting regions of Japan are being explored. The major component of scallop shells is calcium carbonate (CaCO₃), which forms the powerful bactericidal agent, calcium oxide (CaO), when heated. Heated scallop shell powder (HSSP) exhibits strong and broad-spectrum antimicrobial activity against bacteria, fungi, and viruses. This study investigated the antibiofilm activity of HSSP against the biofilms of Campylobacter jejuni, which is the predominant species in campylobacteriosis. Biofilm samples of C. jejuni were prepared on 0.45 µm filter paper under microaerobic conditions. The HSSP treatment inactivated and eradicated C. jejuni biofilms. The resistance of C. jejuni biofilms to HSSP was significantly higher than that of the floating cells. Moreover, the antibiofilm activity of the HSSP treatment against C. jejuni biofilms was higher than that of NaOH treatment at the same pH. These results indicated that HSSP treatment is an effective method for controlling C. jejuni biofilms. Full article

Recently, there has been an increase in the number of food poisoning cases associated with histamine in food, mainly in relation to histamine in fish. Here, we investigated methods to decrease histamine levels in Japanese pilchard, Japanese horse mackerel, and chub Mackerel, stored at 10 °C using various concentrations of heated scallop bioshell calcium oxide (BiSCaO) suspension, dispersion (BiSCaO + Na₂HPO₄), colloidal dispersion (BiSCaO + NapolyPO₄), scallop shell powder (SSP) Ca(OH)₂ in pure water (PW) or saline, and BiSCaO water. BiSCaO in a high alkaline pH solution chemically decomposes histamine poorly, but the partial flocculation/precipitation of histamine was observed with 1 and 0.2 wt.% BiSCaO dispersion and BiSCaO colloidal dispersion, respectively. Cleaning fish samples with BiSCaO suspension, dispersion, colloidal dispersion, or BiSCaO water remarkably reduced histamine levels and normal bacterial flora (coliform bacteria (CF) and total viable bacterial cells (TC)) after storage for four days at 10 °C, while much higher histamine levels were observed after cleaning with saline. These results suggest that cleaning fish with BiSCaO dispersion, colloidal dispersion, or BiSCaO water can significantly reduce histamine levels through their bactericidal activity against histamine-producing bacteria. Full article

Bioshell calcium oxide (BiSCaO) exhibits deodorizing properties and broad microbicidal activity. In this study, we examined possible utility of BiSCaO Water for that purpose. BiSCaO Water was prepared by adding 10 wt% BiSCaO to clean water and gently collecting the supernatant in a bottle. The same volume of clean water was gently poured onto the BiSCaO precipitate and the supernatant was gently collected in a bottle; this process was repeated fifty times. The produced BiSCaO Water contained nanoparticles (about 400–800 nm) composed of smaller nanoparticles (100–200 nm), and was colorless and transparent, with a pH > 12.7. In vitro assays demonstrated that BiSCaO Water eliminated more than 99.9% of influenza A (H1N1) and Feline calicivirus, Escherichia coli such as NBRC 3972 and O-157:H7, Pseudomonas aeruginosa, Salmonella, and Staphylococcus aureus within 15 min. We compared BiSCaO Water with the other microbicidal reagents such as ethanol, BiSCaO, BiSCa(OH)₂ suspensions, povidone iodine, NaClO, BiSCaO dispersion and colloidal dispersion with respect to deodorization activity and microbicidal efficacy. The results showed that BiSCaO Water was a potent reagent with excellent deodorization and disinfection activities against pathogenic bacteria and viruses (including both enveloped and nonenveloped viruses). Full article

Bioshell calcium oxide (BiSCaO) is a scallop-shell powder heated at a high temperature. BiSCaO is composed mainly of calcium oxide and exhibits broad microbicidal properties. The aim of this study is to evaluate the disinfection and decontamination abilities of BiSCaO colloidal dispersions with that of commercially available bioshell calcium hydroxide (BiSCa(OH)₂) following the formation of flocculants/precipitates under strongly alkaline conditions (pH 11.5–12.2). Various concentrations of BiSCaO and BiSCa(OH)₂ colloidal dispersions were prepared by mixing with Na-polyPO₄ (PP) and Na-triPO₄ (TP) as flocculating agents. The microbicidal activities, and the degree of flocculation/precipitation of trypan blue, albumin, chondroitin sulfate, heparin, non-anticoagulant heparin carrying polystyrene (NAC-HCPS), and low-molecular-weight heparin/protamine nanoparticles (LMWH/P NPs) were dependent on the pH, the average particle diameter, and the concentration of BiSCaO or BiSCa(OH)₂ and of the phosphate compound. BiSCaO (average particle diameter: 6 μm) colloidal dispersions (0.2 wt.%) containing 0.15 wt.% PP or TP exhibited substantially stronger microbicidal activity and flocculation/precipitation under strongly alkaline conditions. These results suggest that BiSCaO colloidal dispersions together with phosphate compounds have practical applicability for disinfection. Full article

Scallop-shell powder (SSP) heated at high temperature exhibits high pH and broad antimicrobial activity. Bioshell calcium oxide (BiSCaO) is an SSP composed mainly of calcium oxide. It is poorly water-soluble under alkaline conditions and the generated precipitate can plug spray nozzles. The aim of this study was to establish that BiSCaO dispersion caused no significant CaO loss and plugging of spray nozzles, and to evaluate its deodorization and microbicidal abilities and its ability to reduce the concentrations of NO₂⁻ and NO₃⁻. BiSCaO dispersions were prepared by mixing various concentrations of BiSCaO suspension, while phosphate compounds such as Na₃PO₄, Na₂HPO₄ or NaH₂PO₄ and the pH, average diameter, zeta potential, and form of the compounds with cryo-SEM were evaluated. We evaluated deodorization using tainted pork meat and microbicidal efficacy using contaminated suspension with normal bacterial flora. The concentration of NO₂⁻ and NO₃⁻ after mixing BiSCaO dispersion and pure water containing a high proportion of NO₂⁻ and NO₃⁻ were measured. BiSCaO dispersion formed with Na₂HPO₄, whose ratio to BiSCaO was 60%, showed a high pH (>12), a small particle diameter (>181 nm) and was stable for seven days. The BiSCaO dispersion showed higher deodorization and microbicidal activities than SSP-Ca(OH)₂, which was mainly composed of Ca(OH)₂. BiSCaO, but not SSP-Ca(OH)₂, could reduce the concentration of NO₂⁻ and NO₃⁻ by more than 90% within 15 min. We developed a stable BiSCaO dispersion, and it had high deodorization and microbicidal efficacy. These activities of BiSCaO might result from the high pH caused by CaO hydration and a reduction activity causing active radical species. Full article