Thiamine Dilauryl Sulfate Research Articles

Novel sterilization method combining food preservative use and low temperature steaming for treatment of lignocellulosic biomass with white rot fungi

In the bioconversion of lignocellulosic biomass to useful chemicals, pretreatment of the material prior to hydrolysis is necessary. The aim of the present study was to develop a method to reduce the energy costs of lignocellulosic biomass treatment with white rot fungi. We developed a novel contaminant mold suppressing method combining the food preservative Vitagen AS5N (thiamine dilauryl sulfate) and low temperature steam sterilization (80 °C for 15 min). First, heat-resistant contaminant molds were isolated from sugarcane bagasse (Saccharum officinarum L.) sterilized at 80 °C, and a difference in sensitivity to Vitagen AS5N (200, 300, 500, and 1000 μg/mL, at pH 5.2 and 9.0) was observed between the isolated contaminant molds and white rot fungi. The sugarcane bagasse was subsequently impregnated with Vitagen AS5N solution (500 or 1000 μg/mL at pH 9.0), which did not affect the white rot fungi but suppressed the contaminant molds, and autoclaved at 80 °C. The sterilized sugarcane bagasse medium was inoculated with three types of white rot fungi, and the enzymatic saccharification yield of fungal bagasse was determined after 8 weeks. High enzymatic saccharification yields were attained with each fungal bagasse: 79.5 and 76.2 % for Ceriporiopsis subvermispora (500 and 1000 μg/mL Vitagen AS5N), 80.1 and 79.5 % for Lentinus edodes, and 74.5 and 78.1 % for Coriolus versicolor. These enzymatic saccharification yields were similar to that of normal fungal bagasse. The results indicated that the proposed combination method may potentially reduce the energy required for the treatment of lignocellulosic biomass with white rot fungi.

Studies on Analytical Method of Thiamine Dilaurylsulfate in Soy Sauce

The methods for the determination of thiamine dilaurylsulfate (TLS) in soy sauce have been developed. TLS is a complex of thiamine hydrochloride (TCl) and sodium lauryl sulfate (SLS). The LS portion was determined by the azure A colorimetric method (AA method). Azure A solution and IN sulfuric acid were added to the sample, LS was extracted with chloroform, and then detected at 640nm. The TCl portion was determined by the fluorimetric HPLC method. TCl was converted to its fluorescent derivative, thiochrome, by adding 1% potassium ferricyanide in 20% sodium hydroxide to diluted sample, and neutralizing with phosphoric acid. The thiochrome thus formed was extracted it with isobutanol and then determined by HPLC. Recovery studies of TLS were performed at 3, 5, 10, 12 and 15 ppm (calculated as LS) fortification levels in the samples with both methods. Average recoveries were 98.04-- 98.89% with the AA method and 91.57-92.53 % with the fluori metric HPLC method. Coefficients of variation were less than 5%. The limits of detection of both methods were 0.7ppm. Twenty-seven domestic and thirty-six imported soy sauce samples were analyzed.No TLS was detected in domestic samples, while eight imported samples were found positive for TLS. The data obtained with both methods were practically identical.

Inhibitory effect of ethanol and thiamine dilaurylsulfate against loosely, intermediately, and tightly attached mesophilic aerobic bacteria, coliforms, and Salmonella Typhimurium in chicken skin

The effects of 3 ethanol levels (30, 50, and 70%) with and without thiamine dilaurylsulfate (TDS; 1,000 ppm) were evaluated for the reduction of natural mesophilic aerobic bacteria (MAB), coliforms, and inoculated Salmonella Typhimurium (S. Typhimurium) in chicken skin. The chicken skin was inoculated with a 7 log cfu/mL suspension of S. Typhimurium. Loosely, intermediately, and tightly attached cells were recovered from chicken skin through shaking at 200 rpm for 5 min, stomaching for 1 min, and blending for 1 min, respectively. Increasing the ethanol concentration reduced the number of MAB, coliforms, and S. Typhimurium on the chicken skin, whereas TDS treatment without ethanol was not effective. Intermediately and tightly attached microorganisms (total MAB, coliforms, and S. Typhimurium) were more resistant to chemical disinfectants than loosely attached microorganisms. The combination of 70% ethanol with TDS was most effective than the combination of TDS with lower concentrations of ethanol in reducing populations of loosely, intermediately, and tightly attached MAB (by 1.88 log cfu/g, 1.21 log cfu/g, and 0.84 log cfu/g, respectively), coliforms (by 1.14 log cfu/g, 1.04 log cfu/g, and 0.67 log cfu/g, respectively), and S. Typhimurium (by 1.62 log cfu/g, 1.72 log cfu/g, and 1.27 log cfu/g, respectively). However, the chicken skin treated with higher concentrations of ethanol was tougher (P < 0.05) and more yellow and less red (P < 0.05) than that treated with lower concentrations of ethanol or with water (control). On the other hand, a combination of 30% ethanol and TDS yielded the best results, showing the reduction greater than 0.5 log cfu/g in S. Typhimurium, with no negative effect on chicken skin color or texture. Thus, a combination of 30% ethanol and TDS appears to be the optimal treatment for reducing microbial contamination of skin-on chicken products to enhance poultry safety without decreasing food quality, and this treatment could be applied in the poultry industry.

Sporicidal activities and mechanism of surfactant components against Clostridium sporogenes spores.

The sporicidal activities of seven kinds of antimicrobial agent were investigated in order to screen for novel inactivation agents to apply to Clostridium sporogenes spores. Antimicrobial agents based on surfactant components, as poly-l-lysine, thiamine dilaurylsulfate, and torilin, were more effective than other agents. The degree of spore reduction with 1-2% surfactant components was 1.5-2.5logCFU/mL. The HLB value (hydrophile-lipophile balance) related to denature protein of spores coat on surfactants with sporicidal activity was ranged from 6 to 16. Average HLB value and spore killing effect was inversely correlated. The proteins on spore structures seemed to be disorganized due to binding between polar groups of coats and hydrophilic and hydrophobic groups of surfactant components, resulting in killing of spores. The components that were effective to inactivate C. sporogenes spores had a chemical structure containing CH3, OH, COOH, sulfate groups, and a double bond. Furthermore, hydrophobic surfactants were more effective than hydrophilic surfactants in inactivating spores. This was likely due to the type of hydrophobic surfactant and to the involvement of hydrophobic interactions on coat of spores.

The antimicrobial effect of thiamine dilauryl sulfate in tofu inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes and Bacillus cereus.

Thiamine dilauryl sulfate (TDS) is a food additive that is used as a bactericidal agent. This study examines the antimicrobial effect of TDS on tofu inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Bacillus cereus. Tofu was inoculated with 100μL of each microorganism and TDS solution (0.1, 0.5, 1, and 2%) was added to all bags, which were stored at 5 and 25°C for 5days. Sensory evaluations were conducted with tofu stored at 5°C. At 5°C, with a 2% TDS, E. coli O157:H7, S. Typhimurium, L. monocytogenes, and B. cereus were reduced by 0.29, 0.36, 0.70, and 1.47 log CFU/g, respectively. None of the sensory characteristics of tofu treated with TDS were significantly different from those of the control. Consequently, this study shows the potential of TDS as an antimicrobial agent with a practical application in tofu to ensure food safety.

Inactivation of Salmonella spp. and Listeria spp. by Palmitic, Stearic, and Oleic Acid Sophorolipids and Thiamine Dilauryl Sulfate.

Food contaminated with human pathogens, such as Salmonella spp. and Listeria monocytogenes, frequently causes outbreaks of foodborne illness. Consumer concern over the use of synthesized antimicrobials to enhance microbial food safety has led to a search of natural alternatives. The objectives of this study were to evaluate the antimicrobial activity of various types of sophorolipids (SLs) and thiamine dilauryl sulfate (TDS) against pathogenic Salmonella spp. and Listeria spp. Both free and lactonic forms of SLs were synthesized from Candida bombicola using palmitic, stearic, and oleic acids as co-feedstocks. TDS and purified SLs were used to treat cocktails of Salmonella spp. and Listeria spp. Results showed that lactonic SLs had higher antimicrobial activity than the free-acid form, and Gram-positive Listeria spp. were more susceptible to SLs and TDS than Gram-negative Salmonella spp. Listeria populations were reduced from an initial concentration of 7.2 log CFU/mL to a non-detectible level within a 1 min treatment of 0.1% (w/v) lactonic SLs and TDS in the presence of 20% ethanol, which itself did not significantly reduce the populations. There were no significant differences in the antimicrobial efficacy among palmitic, stearic, and oleic acid-based SLs against Salmonella or Listeria spp. Ethanol was utilized to improve the antimicrobial activity of free-acid SLs against Gram-negative bacteria. In general, TDS was more effective than the SLs against Salmonella and Listeria spp. scanning electron microscopy and transmission electron microscopy images showed that SLs and TDS damaged Listeria cell membranes and resulted in cell lysis. Overall, our results demonstrated that SLs and TDS in the presence of ethanol can be used to inactivate foodborne pathogens, especially Gram-positive bacteria.

Addition of thiamine dilaurylsulfate to reduce the intensity of hydrostatic pressure treatment for microbial safety of Korean Jogaejeot-muchim (salted-fermented-seasoned short-neck clam)

This study investigated hydrostatic pressure (HP) treatment with the addition of thiamine dilaurylsulfate (TDS) for the microbial safety of the final product (salted-fermented-seasoned short-neck clam) during Jogaejeot-muchim manufacturing process. HP treatment (100–600 MPa) was performed at each step (raw, salted-fermented, and salted-fermented-seasoned short-neck clam) of the Jogaejeot-muchim manufacturing process. The reduction effect on Staphylococcus aureus in the salted-fermented-seasoned short-neck clam step was 1.2 log after 400 MPa treatment, and it was lower than those of raw and salted-fermented short-neck clam steps (4.3 and 4.9 log, respectively) after 400 MPa treatment. To improve the microbial safety of the salted-fermented-seasoned short-neck clam step, TDS (1 g/kg) was added, and 1 log reduction was obtained. In the salted-fermented-seasoned short-neck clam step, HP treatment with TDS addition showed a synergistic effect, and the HP intensity for a 2 log reduction was reduced from 500 to 100 MPa treatment with TDS addition, and a 4 log reduction was achieved by the 300 MPa treatment with addition of TDS. This study concluded that the TDS addition contributed to reducing the intensity of HP treatment required for 99 % inactivation of S. a ureus, and that combined treatment (300 MPa treatment with TDS) can be used to provide microbial safety assurance in Korean Jogaejeot-muchim.

Inactivation of Escherichia coli O157:H7 in vitro and on the surface of spinach leaves by biobased antimicrobial surfactants

This study was conducted to evaluate the effect of biosurfactants on the populations of Escherichia coli O157:H7 in suspension and on spinach leaves. Eight surfactants including four soybean oil-based biosurfactants, sodium dodecyl sulfate (SDS), polyoxyethylene sorbitan monooleate (Tween 80), sophorolipid (SO) and thiamine dilauryl sulfate (TDS) at concentrations of 0.1%, 0.5% and 1.0% were tested in bacterial suspension, and the most effective biosurfactants were applied on spinach leaves. Results showed that the soybean oil-based biosurfactants, SDS or Tween 80 did not significantly affect E. coli O157:H7 populations. SO and TDS at concentrations of 1.0% were effective in reducing E. coli O157:H7 populations in bacterial suspension. E. coli O157:H7 with an initial population of 7.1 log CFU/mL was not detectable (detection limit: 1 log CFU/mL) after 1 min in 1.0% TDS or after 2 h in 1.0% SO. On spinach leaves, SO at 1% did not significantly affect E. coli when compared to a water wash during 7 days post-treatment storage at 4 °C. However, TDS (1.0%) wash was as effective as 200 ppm chlorine in reducing population of spot inoculated E. coli O157:H7, achieving 3.1 and 2.7 log CFU/per leaf at day 0, and 1.4 and 1.9 log CFU/leaf at day 7 when compared with a water wash. No apparent change in spinach visual quality was observed. None of treatments caused changes in visual quality of spinach. Electron micrographs suggested ultrastructural damage of bacterial cells such as separation of the outer membrane from the cytoplasmic membrane. Overall, our results showed that SO and TDS may be potential sanitizers in inactivating human pathogens such as E. coli O157:H7 in wash water and on fresh produce.

Sporicidal Activities of Various Surfactant Components against Bacillus subtilis Spores

The sporicidal activities against Bacillus subtilis spores of surfactant components with hydrophilic and hydrophobic properties that can lead to the denaturation of various proteins comprising the spore structure were investigated. The reduction in spore numbers by each of the surfactant components bornyl acetate, geranyl acetate, pinene, p-cymene, camphene, citral, 2,3-dihydrobenzofuran, polylysine, and thiamine dilaurylsulfate at 1% was estimated at 1 to 2 log CFU/ml. The average hydrophile-lipophile balance value of surfactants with sporicidal activity causing a reduction of 1 to 2 log CFU/ml was 9.3, with a range from 6.7 to 15.8, which is similar to the values of various chemical surfactants of 9.6 to 16.7. The results also showed that the surfactants that were hydrophobic were more effective than those that were hydrophilic in killing B. subtilis spores. Furthermore, the sporicidal effect of surfactants like geranyl acetate and γ-terpinene was significantly enhanced in the presence of a germinant, because l-alanine and synergistic cofactors (e.g., K+ ions) trigger cortex hydrolysis in spores.

Effect of thiamine dilaurylsulfate against Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes and Bacillus cereus spores in custard cream

This study was conducted to investigate the antimicrobial effect of thiamine dilaurylsulfate (TDS), known as a vitamin B1 derivative, on custard cream. The inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Bacillus cereus spores in custard cream over a 5 day storage period and the influence of storage temperature at 4 and 25 °C were investigated. Samples were inoculated with a cocktail of these pathogens and subjected to addition of TDS at concentrations ranging from 0 to 2%. As the concentration of TDS and storage time increased, the inactivation effect increased among all tested pathogens except for B. cereus. The addition of 2% TDS achieved 2.43-, 2.37-, and 0.93-log reductions in inoculated E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, during 5 day storage at 25 °C. Gram-negative bacteria were more susceptible to TDS than Gram-positive bacteria, and TDS was more effective at 25 °C than 4 °C. However, regardless of TDS concentration during storage at 4 and 25 °C, there were no significant (P > 0.05) differences in populations of B. cereus spores between untreated control and TDS-treated samples. These results suggest that TDS has potential for preventing spoilage of dairy products by improving microbiological safety.

Evaluation of the removal and destruction effect of a chlorine and thiamine dilaurylsulfate combined treatment on L. monocytogenes biofilm.

The present study investigated the efficacy of single and combined treatment of both chlorine and thiamine dilaurylsulfate (TDS) on the reduction of Listeria monocytogenes biofilms in microtiter plate. The disinfectants used in this study were 50, 100, and 200 mg/L chlorine and 100, 500, and 1000 mg/L of TDS. Biofilm-forming index (BFI) and culturable cell count were used to evaluate the disinfectant assay. The highest BFI reduction was 0.80, achieved by the combination of 200 mg/L chlorine and 1000 mg/L TDS. In contrast, the highest culturable cell count reduction was 4.80 log colony-forming units/well by the combination of 200 mg/L chlorine and 100 mg/L TDS. The BFI was reduced in a concentration-dependent manner while culturable cell count was significantly reduced only when all chlorine concentration was combined with 100 mg/L TDS. However, when chlorine was combined with a higher concentration of TDS, the reduction decreased significantly. The result in this study showed that the combination of the 200 mg/L chlorine and 1000 mg/L TDS could be a practical application in removing L. monocytogenes biofilms from surfaces in food industry, and for the 200 mg/L chlorine and 100 mg/L, it can be used for killing the pathogen biofilms. However, more studies are still needed in order to show its efficacy on foods surfaces as well as to develop an even more effective treatment in both killing and removing biofilms.

Combined effects of chlorine and thiamine dilauryl sulfate on reduction of Listeria monocytogenes in chicken breast and development of predictive growth models

The inhibitory effect of chlorine (50, 100, and 200 mL/kg) and thiamine dilauryl sulfate (TDS: 100, 500, and 1,000 mg/kg) on Listeria monocytogenes in chicken breast was investigated. Also, predictive growth models as a function of chlorine and TDS concentration, and storage temperature (4, 10, and 15°C) were developed using a polynomial model. Listeria monocytogenes counts were significantly (P < 0.05) different in samples treated with sterile distilled water and combinations of chlorine and TDS. The maximum reduction effect was 0.5 log cfu/g by combined treatment of 200 mL/kg chlorine and 1,000 mg/kg TDS. The largest synergistic effect was 0.38 log cfu/g by combined treatment of 100 mL/kg chlorine and 1,000 mg/kg TDS. The primary models that were developed to obtain the specific growth rates (SGR) and lag time (LT) had good fitness (R2 > 0.91) determined by the reparameterized Gompertz equation. The secondary polynomial models were calculated by nonlinear regression analysis. In the validation of the developed models, the bias factor (Bf) and accuracy factor (Af) for SGR were 0.54 and 1.84, respectively, whereas those for LT were 0.97 and 1.04, respectively. In quality analysis, chlorine and TDS did not change the color or texture of chicken breast meat during storage at 4°C for 7 d. Thus, our findings indicate that a combined treatment of 100 mL/kg chlorine and 1,000 mg/kg TDS appears to an effective method into reduce L. monocytogenes in broiler carcasses with no negative effects on color and textural quality. The predictive models were in good agreement with the validation and may be used to predict L. monocytogenes growth in chicken breast.

The evaluation of combined chemical and physical treatments on the reduction of resident microorganisms and Salmonella Typhimurium attached to chicken skin

This study was conducted to evaluate the efficacy of sodium hypochlorite (NaOCl, 0-200 mg/kg), thiamine dilauryl sulfate (TDS, 1,000 mg/kg), and ultrasound (37 kHz, 380 W) on reducing Salmonella Typhimurim, mesophilic aerobic bacteria (MAB), and coliforms on chicken skin. Chemical and physical treatments were applied for 5 min either singly or jointly, and Salmonella previously inoculated on chicken skin were quantitatively assessed using brilliant green agar, and the populations of MAB and coliforms in the native flora were enumerated using plate count agar and violet red bile agar, respectively. In the evaluation of bacterial attachment/detachment, chicken skin was quantitatively assessed for loosely, intermediately, and tightly attached bacteria. The treatment effects on bacteria detachment were also visualized using field emission scanning electron microscopy. In addition, color and textural properties of the skin after treatments were evaluated using a color difference meter and texture analyzer. Antimicrobial activity of NaOCl increased as the NaOCl concentration was increased, especially for loosely attached cells. The combination of 200 mg/kg NaOCl and ultrasound (NaOCl/ultrasound) significant reduced loosely, intermediately, and tightly attached bacteria populations by 0.75 to 0.47, 0.43 to 0.41, and 0.83 to 0.54 log cfu/g for MAB, coliforms, and Salmonella Typhimurium, respectively. However, the combination of NaOCl and TDS (NaOCl/TDS) did not sufficiently reduce those cells on chicken skins, except for loosely attached MAB and coliforms. The NaOCl/ultrasound combination produced a higher reduction in numbers of inoculated and native bacteria flora than any single application, with no negative effect on skin color or texture. Generally, the loosely attached bacteria were less resistant to the chemical and physical treatments than the intermediately and tightly attached bacteria in chicken skin, presumably due to their location in deeper skin layer and crevices. Further research is needed to investigate how the intermediately and tightly attached microorganisms can be effectively eliminated from chicken skin.

항균 효능이 있는 비타민 B1 유도체(Thiamine Dilauryl Sulfate:TDS)의 나노입자화를 통한 기능성 향장 활성 증진

본 연구는 레시틴으로 나노입자화 시킨 티아민 디라우릴 설페이트의 향장활성 증진에 관한 것이다. TDS를 포집시킨 나노입자는 150 ~ 200 nm의 크기를 나타내는 구형이며, 또한 제타포텐셜을 측정하여 여러 pH 범위에서 안정한 것을 확인하였다. TDS 나노입자는 인간 섬유아세포(CCD-986sk)에 높은 농도를 처리하여도 85%의 세포생존률을 보였다. 자유라디칼소거활성 실험을 진행한 결과 나노입자화하지 않은 TDS 희석액(1.0 mg/mL)은 81.6%의 활성을 나타내었고, 나노입자화한 TDS 용액은 이보다 더 높은 88.1%의 높은 라디칼 소거활성을 보였다. TDS 나노입자는 자외선을 조사시킨 CCD-986sk에서 MMP-1의 발현을 41.4% 감소시켰다. TDS 용액과 TDS 나노입자를 가지고 salmonella typhimurium, listeria monocytogenes에 대하여 항균활성을 측정하였다. TDS 나노입자의 경우 양성대조군의 항균활성과 비슷한 결과를 나타내었다. 이러한 결과들로 TDS 나노입자가 항산화, 미백, 주름개선 효능같은 향장 소재로서의 적용이 가능할 것이라 생각된다. This study was to improve cosmetical activity of thiamine di-lauryl sulfate (TDS) by encapsulation of nanoparticle with lecithin. Results showed that most of the nanoparticles containing the TDS were well formed in round shape with below 150 ~ 200 nm diameter as well as they were fairly stable in various pH ranges by measuring zeta potentials. The nanoparticles of TDS resulted in 85% cell viability of human normal fibroblast cells (CCD-986sk) when added at the highest concentration (1.0 mg/mL). The nanoparticles of Acer mono sap showed highest free radical scavengering effect as 88.1% in adding sample (1.0 mg/mL), compared to TDS solution of non-encapsulation (81.6%). The nanoparticles of TDS reduced the expression of MMP-1 on UV-irradiated CCD-986sk cells down to as 41.4%. The TDS solution and nanoparticles showed significant anti-microbial activities agaionst the salmonella typhimurium and listeria monocytogenes at 5 and 6 days as compared with control. Anti-microbial activities of TDS nanoparticles were similar to positive control. These results indicated that TDS nanoparticles may be a source for functional cosmetic agents capable of improving cosmetical activity such as antioxidant, whitening, and anti-wrinkling effects and can be further developed as natural preservative in cosmetics.

Effect of Nanoencapsulated Vitamin B1 Derivative on Inhibition of Both Mycelial Growth and Spore Germination of Fusarium oxysporum f. sp. raphani.

Nanoencapsulation of thiamine dilauryl sulfate (TDS), a vitamin B1 derivative, was proved to effectively inhibit the spore germination of Fusarium oxysporum f. sp. raphani (F. oxysporum), as well as mycelial growth. The average diameter of nanoparticles was measured as 136 nm by being encapsulated with an edible encapsulant, lecithin, whose encapsulation efficiency was about 55% in containing 200 ppm of TDS concentration: the 100 ppm TDS nanoparticle solution showed a mycelial growth inhibition rate of 59%. These results were about similar or even better than the cases of treating 100 ppm of dazomet, a positive antifungal control (64%). Moreover, kinetic analysis of inhibiting spore germination were estimated as 6.6% reduction of spore germination rates after 24 h treatment, which were 3.3% similar to the case of treating 100 ppm of a positive control (dazomet) for the same treatment time. It was also found that TDS itself could work as an antifungal agent by inhibiting both mycelial growth and spore germination, even though its efficacy was lower than those of nanoparticles. Nanoparticles especially played a more efficient role in limiting the spore germination, due to their easy penetration into hard cell membranes and long resident time on the surface of the spore shell walls. In this work, it was first demonstrated that the nanoparticle of TDS not a harmful chemical can control the growth of F. oxysporum by using a lower dosage than commercial herbicides, as well as the inhibiting mechanism of the TDS. However, field trials of the TDS nanoparticles encapsulated with lecithin should be further studied to be effectively used for field applications.

E. Coli O157:H7 Population Reduction from Alfalfa Seeds with Malic Acid and Thiamine Dilauryl Sulfate and Quality Evaluation of the Resulting Sprouts

It has been reported that washing seeds with a 20000 ppm Ca(OCl)(2) solution as recommended by the U.S. Food and Drug Administration is unable to eliminate E. coli cells attached to seed surfaces, and the bacterial cells that have survived a sanitation wash can proliferate during sprouting to a high population. The objectives of this research were to examine the efficacy of malic acid (MA) and thiamine dilauryl sulfate (TDS) combined treatments on the inactivation of E. coli O157:H7 on alfalfa seeds, to study the growth of the remaining E. coli cells during sprouting, and to evaluate the sprout quality. When 10 g of inoculated alfalfa seeds were washed in a 10% MA-1% TDS solution, a complete elimination of E. coli was achieved. The same result was observed by washing the seeds in a 20000 ppm Ca(OCl)(2) solution. However, when the seed size was increased to 50 g while maintaining the same seed-to-sanitizer ratio, both the MA + TDS and the 20000 ppm chlorine washes failed to completely inactivate the E. coli cells on the seeds. Nevertheless, the 10% MA-1% TDS solution was significantly more effective in E. coli count reduction compared to the 20000 ppm chlorine wash. The E. coli O157:H7 cells remaining on the seeds after treatments with both sanitizers grew up to 7 to 8 log CFU/g sprout after 96 h of sprouting. Under the treatment conditions used in this study, none of the treatments resulted in significant differences in germination rate, yield, or quality of the sprouts. The malic acid (MA) and thiamine dilauryl sulfate (TDS) combined treatment may provide a new solution to secure the microbial safety of seeds and sprouts. An important finding of this study is that seed sample size has a significant impact on the inactivation of E. coli O157:H7 on alfalfa seeds. The microbial inactivation results obtained in a laboratory set-up cannot be directly applied to a large scale operation. A validation test on the large scale has to be performed to evaluate the efficacy of the sanitizer.

Effect of surface roughness on inactivation of Escherichia coli O157:H7 87-23 by new organic acid-surfactant combinations on alfalfa, broccoli, and radish seeds.

Surface roughness has been reported as one of the factors affecting microbial attachment and removal. Seed surfaces are complex, and different seed varieties have different surface topographies. As a result, a sanitizer effective in eliminating pathogenic bacteria on one seed may not be as effective when applied to another seed. The objectives of this research were (i) to investigate the efficacy of malic acid and thiamine dilaurylsulfate (TDS) combined treatments for inactivation of E. coli O157:H7 strain 87-23 on alfalfa, broccoli, and radish seeds, (ii) to quantify surface roughness of the seeds, and (iii) to determine the correlation between microbial removal and surface roughness. The surface roughness of each seed type was measured by confocal laser scanning microscopy (CLSM) and surface profilometry. Surface roughness (Ra) values of the seeds were then calculated from CLSM data. Seeds inoculated with E. coli O157:H7 87-23 were washed for 20 min in malic acid and TDS solutions and rinsed for 10 min in tap water. Radish seeds had the highest Ra values, followed by broccoli and alfalfa seeds. A combination of 10% malic acid and 1% TDS was more effective than 20,000 ppm of Ca(OCl)(2) for inactivation of E. coli O157:H7 87-23 on broccoli seeds, while the inactivation on radish and alfalfa seeds was not significantly different compared with the 20,000-ppm Ca(OCl)(2) wash. Overall, a negative correlation existed between the seeds' Ra values and microbial removal. Different seeds had different surface roughness, contributing to discrepancies in the ability of the sanitizers to eliminate E. coli O157:H7 87-23 on the seeds. Therefore, the effectiveness of one sanitizer on one seed type should not be translated to all seed varieties.

비타민 B1 유도체 Thiamine Dilauryl Sulfate의 나노 입자 제조를 통한 수용액의 용해도에 따른 항진균 활성 평가

Conventional Thiamine Dilauryl Sulfate (TDS) powder has a low stability. In order to solve this problem, this study was performed to improve the solubility of TDS. The process for enhance solubility of TDS was nano grinding mill and ultrasonic dispersion process. TDS paticle was manufactured to nano size through nano grinding mill process. The size of TDS nanoparticle was measured as average 220 ㎚ by DLS. And The TDS nanoparticle in water solution manufactured through ultrasonic dispersion process. The TDS nanoparticle in water solution was showed the highest solubility with 40% ethanol. These results was increased the concentration of TDS from 200 ppm to 240 ppm in water solution. The TDS nanoparticle in water solution showed diameter of Colletotrichum gloeosporioides growth with smaller than about 1.56 ㎝ compared to the TDS paticle in water solution at same concentration. Also, TDS nanoparticle in water solution showed growth inhibition activity as 59.2% with higher than about 10% compared to the TDS paticle water solution in same concentration. Finally, TDS nanoparticle in water solution was increased solubility through nano grinding mill and ultrasonic dispersion process. Also, the increase of concentration in TDS nanopaticle in water solution according to solubility enhancement lead to an result enhancement of antifungal activity. Consequently, we suggested that the TDS nanoparticle in water solution was more effective than TDS particle in water solution owing to the sub-cellular particle size, ability to persistence and targeting to cell membrane of Colletotrichum gloeosporioides. Furthermore we expected the applicating possibility with bio pesticide.

비타민 B1 유도체(Thiamine Di-lauryl Sulfate:TDS)의 나노입자화를 통한 고추탄저병균의 항진균 활성 증진

This study was performed to enhance antifungal activity of anthracnose in chili pepper by nanopaticles of thiamine di-lauryl sulfate (TDS) through high pressure homogenization process. Yield of TDS was 79.14% by reaction of thiamine hydrochloride and sodium lauryl sulfate. TDS nanopaticle solution was manufactured through high pressure homogenization process. The turbidity of nanoparticles solution was increased with increasing the concentration of TDS, and nanoparticles solution of 100 ppm was showed the highest turbidity with absorbance of 3.212. The size of nanoparticles solution was measured as average 258.6㎚ by DLS. Nanoparticles solution of 100 ppm showed growth inhibition activity with higher than about 80% compared to the control group against Colletotrichum gloeosporioides. Finally, nanoparticles solution was increased effectively the penetration of the TDS nanopaticles on attached cell membrane of hyphae and started to destruct the cells under microscope observation. Consequently, we suggested that the TDS nanoparticle solution by high pressure homogenization process might be suitable biochemical pesticides for improving the antifungal activities against anthracnose in pepper.

SYNERGISTIC EFFECT OF VITAMIN B1 ON SANITIZER AND DISINFECTANT TREATMENTS FOR REDUCTION OF BACILLUS CEREUS IN RICE

ABSTRACT The synergistic bactericidal effects of vitamin B1 (thiamine dilauryl sulfate) and the efficacy of commercial sanitizers for minimization of Bacillus cereus contamination in cooked rice were investigated. Sanitizer‐treated rice exhibited a greater reduction than water‐treated rice, while sanitizer‐treated rice with Vitamin B1 produced an even greater reduction. The treatments for B. cereus in rice included (1) 100 ppm hydrogen peroxide with 500 ppm vitamin B1; (2) 200 ppm hydrogen peroxide with 100 ppm vitamin B1; (3) 400 ppm hydrogen peroxide; (4) 50 ppm chlorine with 500 ppm vitamin B1; (5) 60 ppm chlorine with 300 ppm vitamin B1; (6) 70 ppm chlorine with 100 ppm vitamin B1; (7) 80 ppm chlorine; and (8) 100,000 ppm ethanol with 500 vitamin B1. All treatments completely eliminated B. cereus in rice. The sensory properties of all sanitizer‐treated cooked rice did not differ significantly from the same properties for water‐treated cooked rice.PRACTICAL APPLICATIONSThe prevalence of Bacillus cereus in rice and rice products has been documented and control of the growth of B. cereus in rice is an important consideration. The results obtained from this study can be of use to rice producers in the manufacture of safe products. Although chemical disinfectants can be used to reduce the amount of B. cereus in rice, vitamin B1 can also be used as an effective additive that reduces the amount of disinfectant use via a synergistic antimicrobial effect. The increasing use of chemical disinfectants for safety in the food industry can be reversed using our method.