Concentrations Of Trisodium Phosphate Research Articles

Comparative study of corrosion inhibition effect on steel rebars in carbonated concrete-pore-solutions: Tolyltriazole vs. sodium phosphate

Concrete structures exposed to carbonated environments are susceptible to steel reinforcement corrosion, leading to structural deterioration and reduced service life. In this research, the effectiveness of two commonly used corrosion inhibitors, tolyltriazole (TTA) and trisodium phosphate (TSP), in carbonated concrete pore (CCP) solutions was compared to enhance the corrosion resistance of steel rebar. The study involved the preparation of simulated carbonated concrete pore solutions to mimic the environment of concrete structures exposed to carbonation. The concrete-pore solutions were simulated by immersing the specimens in a carbonation chamber. Electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) tests were performed to evaluate the corrosion resistance of the steel rebars. The corrosion potential, polarization resistance, and corrosion current density were measured and compared among the different groups. Additionally, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses were conducted to examine the surface morphology, chemical composition and corrosion products formed on the steel rebars. The CCP solution with equal concentrations of TTA and TSP demonstrated the highest corrosion resistance and corrosion inhibition efficiency. TTA and TSP effectively inhibit pitting corrosion of steel in CCP solution, according to SEM, EDS, and XPS analyses. The findings suggested that there is a competitive interaction between phosphate ions and TTA on the steel surface, leading to an antagonistic impact on corrosion inhibition. It was suggested that the [Fen(TTA)p]m complex would produce a protective coating on the surface of steel, which would act as a synergistic inhibitor.

Effect of trisodium phosphate treatment on black spot of apple fruit and the roles of anti-oxidative enzymes

Black spot caused by Alternaria alternata is an important postharvest disease of apple fruit. In this study, apple fruit (cv. Golden delicious) was used as the materials to study the effects of 0.25, 0.5, 1.0, 2.0 mg/mL trisodium phosphate (TSP) dipping treatment on lesion development of fruit inoculated with A. alternata. In vitro test was conducted to investigate the effect of TSP on mycelia growth of A. alternata. The optimal concentration of TSP was screened to assay its effect on the activity of anti-oxidative enzymes, the content of H2O2 and phenylpropane metabolites in apple fruit. The results showed that the different concentrations of TSP significantly inhibited mycelia growth of A. alternata and indicated dose dependent. TSP treatment also inhibited lesion development of apple fruit inoculated with A. alternata. According these results, 0.5 mg/mL TSP was chose for the following study. The results also indicated that TSP treatment enhanced the activity of phenylalanine ammonialyase, peroxidase, catalase, ascorbate peroxidase, superoxide dismutase, glutathione reductase, increased H2O2 accumulation and total phenolic compounds, flavonoids and lignin contents in apple fruit. All these results suggest that enhanced disease resistance in apple fruits by TSP against A. alternata is associated with increasing anti-oxidative enzymes activities and accumulation of phenylpropane metabolites.

Trisodium phosphate and sodium hypochlorite are more effective as antimicrobials against Campylobacter and Salmonella on duck as compared to chicken meat

Little work has been reported on the use of commercial antimicrobials against foodborne pathogens on duck meat. We investigated the effectiveness of trisodium phosphate (TSP) and sodium hypochlorite (SH) as antimicrobial treatments against Campylobacter and Salmonella on duck meat under simulated commercial water chilling conditions. The results were compared to the same treatments on well-studied chicken meat. A six strain Campylobacter or Salmonella cocktail was inoculated (5ml) at two dilution levels (104 and 108cfu/ml) onto 25g duck or chicken meat with skin and allowed to attach for 10min. The meat was exposed to three concentrations of pH adjusted TSP (8, 10 and 12% (w/v), pH11.5) or SH (40, 50 and 60ppm, pH5.5) in 30ml water under simulated spin chiller conditions (4°C, agitation) for 10min. In a parallel experiment the meat was placed in the antimicrobial treatments before inoculation and bacterial cocktails were added to the meat after the antimicrobial solution was removed while all other parameters were maintained. Untreated controls and controls using water were included in all experiments. Bacterial numbers were determined on Campylobacter blood-free selective agar and Mueller Hinton agar or xylose deoxycholate agar and tryptone soya agar using the thin agar layer method for Campylobacter and Salmonella, respectively. All TSP concentrations significantly (p<0.05) reduced numbers of Campylobacter (~1.2–6.4logcfu/cm2) and Salmonella (~0.4–6.6logcfu/cm2) on both duck and chicken meat. On duck meat, numbers of Campylobacter were less than the limit of detection at higher concentrations of TSP and numbers of Salmonella were less than the limit of detection at all concentrations of TSP except one. On chicken meat, numbers of Campylobacter and Salmonella were less than the limit of detection only at the lower inoculum level and higher TSP concentrations. By contrast only some of the concentrations of SH significantly (p<0.05) reduced numbers of Campylobacter and Salmonella (~0.2–1.5logcfu/cm2) on both duck and chicken meats. None of the SH treatments resulted in numbers of either pathogen being less than limit of detection. Results indicate that chicken meat has the ability to effectively protect Campylobacter and Salmonella against the impact of trisodium phosphate and sodium hypochlorite while duck meat does not. This study suggests that trisodium phosphate has a strong potential for application in a commercial poultry processing to reduce Campylobacter and Salmonella specifically on duck meat.

Solubility of CO2 in aqueous TSP

The experimental results for CO2 absorption in aqueous tri sodium phosphate (TSP) were presented for total TSP concentrations from 1.0 to 2.0kmol/m3, temperatures from 303.14 to 333.14K and inlet CO2 partial pressures from 10.13 to 20.26kPa. The solubility of CO2 increased with increasing concentrations of TSP from 1.0 to 2.0kmol/m3 at fixed CO2 partial pressure and temperature. Temperature showed positive effect on CO2 solubility and it was increased continuously from 313.14 to 333.14K. The solubility of CO2 also increased slightly with inlet partial pressure of CO2 in the gas stream. The maximum CO2 solubility in TSP was found as 0.960molCO2/mol absorbent at 333.14K and 2.0kmol/m3 TSP concentration. The results of experimental CO2 solubility in aqueous TSP was compared to monoethanol amine (MEA) and other amines mostly used in acid gas treating.

Cellular Response of Campylobacter jejuni to Trisodium Phosphate

The highly alkaline compound trisodium phosphate (TSP) is used as an intervention to reduce the load of Campylobacter on poultry meat in U.S. poultry slaughter plants. The aim of the present study was to investigate the cellular responses of Campylobacter jejuni NCTC11168 when exposed to sublethal concentrations of TSP. Preexposure of C. jejuni to TSP resulted in a significant increase in heat sensitivity, suggesting that a combined heat and TSP treatment may increase reduction of C. jejuni. A microarray analysis identified a limited number of genes that were differently expressed after sublethal TSP exposure; however, the response was mainly associated with ion transport processes. C. jejuni NCTC11168 nhaA1 (Cj1655c) and nhaA2 (Cj1654c), which encode orthologues to the Escherichia coli NhaA cation/proton antiporter, were able to partially restore TSP, alkaline, and sodium resistance phenotypes to an E. coli cation/proton antiporter mutant. In addition, inhibition of resistance-nodulation-cell division (RND) multidrug efflux pumps by the inhibitor PaβN (Phe-Arg β-naphthylamide dihydrochloride) decreased tolerance to sublethal TSP. Therefore, we propose that NhaA1/NhaA2 cation/proton antiporters and RND multidrug efflux pumps function in tolerance to sublethal TSP exposure in C. jejuni.

EFFICACY OF TRISODIUM PHOSPHATE IN KILLING ACID‐ADAPTED SALMONELLA TYPHIMURIUM

ABSTRACTThe influence of acid adaptation on Salmonella Typhimurium tolerance to alkaline stress was studied using cells grown in buffered‐brain heart infusion (BHI) (pH 7.0) and BHI acidified up to pH 4.5 with acetic, citric, lactic and hydrochloric acids, and challenged in BHI containing 1.5%, 2.0% or 2.5% trisodium phosphate (TSP; pH 10.0, 10.5, 11.0, respectively) or NaOH at the same pH values. TSP was more effective in killing S. Typhimurium than NaOH (D values at pH 10.0, 10.5 and 11.0 of 28.3, 9.7, 2.77 min and 150.2, 31.5, 5.09 min with TSP and NaOH, respectively). Acid‐adapted cells showed a cross‐protection response to NaOH, with D values around twofold higher than those corresponding to nonacid‐adapted cells. However, they were more sensitive to a TSP treatment. These findings suggest that both alkalinizing compounds damage the cellular membrane in a different extent. A linear relationship between log of D values and treatment pH was found, obtaining zpH values (change in pH required for a 10‐fold reduction of D values) of 0.99 and 0.67 with TSP and NaOH, respectively. A surface response model was developed describing the combined effects of treatment pH and TSP concentration, which could prove useful for the food industry in determining appropriate processing conditions for decontamination purposes.PRACTICAL APPLICATIONSChemical decontamination processes are usually applied to reduce the potential pathogens load on food surfaces. This study explores the use of trisodium phosphate (TSP) as a decontamination agent effective in inactivating Salmonella Typhimurium in acidic foods, which represents a great concern for the food industry, health regulatory officials and consumers. A mathematical model has been developed, which enable us to predict the effect of treatment pH and TSP concentration on the inactivation of this pathogenic microorganism which could prove useful for the food industry.

Efficacy of Chemical Treatments Against Murine Norovirus, Feline Calicivirus, and MS2 Bacteriophage

Human noroviruses pose an emerging public health threat, and despite stringent control strategies, variant strains continue to spread and cause disease outbreaks. Routinely used chemical sanitizers, such as sodium hypochlorite though effective on food contact surfaces, require high concentrations to cause reduction in enteric viral titers. The aim of this study was to evaluate the efficacy of trisodium phosphate (TSP) against three human enteric virus surrogates, murine norovirus (MNV-1), feline calicivirus (FCV), and bacteriophage MS2 in comparison to routinely used sanitizers. Three concentrations of TSP (1%, 2%, and 5%) at different contact times (30 sec and 1 min) were evaluated against the surrogate viruses individually inoculated on formica coupons. Our results showed that 5% TSP was effective in obtaining a >or=6 log(10) PFU reduction for MNV-1, FCV, and MS2 after a contact time of only 30 sec or 1 min similar to 10% household bleach (0.6% sodium hypochlorite, 5000 ppm available chlorine) for high titers of FCV and MS2, and with approximately 5 log(10) reduction after either 30 sec or 1 min on low viral titers. However, 2% TSP for 1 min resulted in >or=6 log(10) PFU reduction for FCV and MS2, but only a 1.05 log(10) PFU reduction for MNV-1 at high titers, with similar results after 30 sec. Decreasing TSP levels to 1% reduced FCV by approximately 2.65 log(10) PFU, MS2 by 4.5 log(10) PFU at high titers, and no reduction for MNV-1 after 30-sec or 1 min contact. Glutaraldehyde (2%) reduced FCV and MNV-1 titers by approximately 6 log(10) PFU; however, MS2 was reduced by only 3.22 and 3.74 log(10) PFU after 30 sec and 1 min, respectively, while 70% ethanol was not effective in reducing the three viruses at either high or low titers at both contact times. Alternative control strategies using TSP with short contact times should benefit the food industry in reducing norovirus transmission.

EFFECTS OF TRISODIUM PHOSPHATE ON POPULATIONS OFSALMONELLA TYPHIMURIUMANDSALMONELLA ENTERITIDIS IN VITRO

This study determined the bactericidal activity of different concentrations of trisodium phosphate (TSP) against Salmonella typhimurium and Salmonella enteritidis in vitro. One milliliter of each TSP solution (0.5, 1, 1.5 and 2% w/v) was mixed with 1 mL of each bacterial culture and left to stand at room temperature (18 ± 1C) for 0, 15, 30, 45, 60 or 90 min before enumeration of the surviving pathogens. The effects of 1.5 and 2% TSP were apparent on both bacterial species from 0 min and bacterial counts reached undetectable (<1.0 × 101 cfu/mL) levels immediately. The 1% TSP solution effected close to 4.20–5.72 log reduction after 15 min. However, the reduction effect of 0.5% TSP was a function of treatment time, and some culturable bacteria remained even after 90 min of treatment. These results suggest that the bactericidal effect of TSP solution on these pathogens depends on its concentration and on the duration of treatment. PRACTICAL APPLICATIONS Poultry has been identified as one of the most important reservoirs of Salmonella typhimurium and Salmonella enteritidis in food chain. Efforts to eliminate or reduce Salmonella spp. and other pathogens attached to poultry carcasses during processing have been made for many years. In 1992, the U.S. Department of Agriculture approved the use of trisodium phosphate (TSP) as a processing aid to reduce Salmonella spp. on raw poultry carcasses. The aim of the present study was to determine the bactericidal effects of different concentrations of TSP on pure cultures of these pathogens in vitro.

Effectiveness of Trisodium Phosphate against Listeria monocytogenes on Excised and Nonexcised Chicken Skin

The influence of sample type (i.e., excised versus nonexcised chicken skin) on the efficiency of trisodium phosphate (TSP) solutions in reducing Listeria monocytogenes populations and inhibiting their growth during refrigerated storage was studied. Whole chicken legs and excised chicken leg skin fragments inoculated with 108 CFU of L. monocytogenes per ml were dipped for 15 min in sterile tap water (control) or in a solution containing 8, 10, or 12% TSP. L. monocytogenes counts were determined after 0, 1, 3, and 5 days of refrigerated storage (2°C). The decontamination effect of TSP was greater for excised skin than for whole legs. Microbial differences between control and TSP-treated samples were significantly larger for excised skin than for whole legs for 9 (75%) of 12 tested combinations of TSP concentrations and storage times. These differences varied from 1.05±0.26 log10 cycles (day 1) to 3.30±0.14 log10 cycles (day 5) for nonexcised-skin samples (whole legs) and from 1.54±0.48 log10 cycles (day 1) to 4.28±0.86 log10 cycles (day 5) for excised-skin samples. Significantly larger reductions were observed from the third day of refrigerated storage onward. The TSP concentration was a significant factor in the reduction of L. monocytogenes populations. These results suggest that bacteria are more readily accessible to TSP in excised than in nonexcised chicken skin and that the type of sample used to ascertain the efficacy of antimicrobial surface treatments may influence the findings of this type of study.

Influence of Poultry Carcass Skin Sample Site on the Effectiveness of Trisodium Phosphate against Listeria monocytogenes

The aim of this study was to determine the influence of skin sample site on the efficacy of trisodium phosphate (TSP) solutions in reducing Listeria monocytogenes populations on chicken carcasses during refrigerated storage. Chicken skin samples from the legs, the breasts, and the dorsal area inoculated with L. monocytogenes (108 CFU/ml) were dipped for 15 min in sterile tap water (control) or in 8, 10, or 12% TSP. L. monocytogenes counts and surface pH values were determined after 0, 1, 3, and 5 days of storage at 2°C. For all sampling times and TSP concentrations, the reductions in L. monocytogenes numbers in breast skin were significantly larger (P < 0.05) than those in leg skin or dorsal skin. No significant differences were found in pH values as an effect of skin site. Our results suggest that skin sampling site is an important factor that needs to be considered when decontamination protocols are developed for poultry carcasses with the TSP treatment.

Efficacy Enhancement of Trisodium Phosphate against Spoilage and Pathogenic Bacteria in Model Biofilms and on Adipose Tissue

A two-step approach for enhancing the efficacy of trisodium phosphate (TSP) was evaluated using meat spoilage and pathogenic bacteria in flow cell biofilms and adipose tissue model systems. The process was based on the plasmolysis of attached bacteria (biofilms) with a hyperosmotic solution (1.5M NaCl) and the subsequent deplasmolysis of cells with a low-osmotic-strength solution containing different concentrations of TSP (0.1, 0.25, 0.5, 0.625, and 1.0% [wt/vol]). Escherichia coli, Salmonella Enteritidis, Pseudomonas sp., Listeria monocytogenes, and Brochothrix thermosphacta strains were cultivated for 24 h as pure culture biofilms in glass flow cells with complex media and were then treated with either 0.1, 0.25, 0.5, 0.625, and 1.0% TSP, or the same TSP concentrations delivered in conjunction with plasmolysis-deplasmolysis (PDP). Confocal scanning laser microscopy, a commercial fluorescent viability probe, and image analysis were then used to quantify the relative abundances of living and dead cells remaining after the different treatment regimes. With the exception of L. monocytogenes (which was resistant to TSP concentrations of up to 5%), the PDP process increased the sensitivity of the test strains to TSP. However, when similar experiments were conducted with pork adipose tissue, it became evident that higher TSP concentrations were necessary to produce significant decreases in the number of viable cells and that the PDP process generally failed to enhance TSP efficacy. An exception was L. monocytogenes, which exhibited an increase in sensitivity to TSP when inoculated tissue was pretreated with 1.5M NaCl. It is thought that factors contributing to the failure of the PDP process to enhance the activity of TSP in meat systems involves the mode of TSP antimicrobial activity, alkaline pH stress, and the chemically complex, buffered nature of meats. It remains to be determined whether the PDP process is suitable for use with other food grade antimicrobial agents or can be used in nonfood biofilm control applications.

Efficacy of Trisodium Phosphate Solutions in Reducing Listeria monocytogenes Populations on Chicken Skin during Refrigerated Storage

Chicken skin inoculated with 108 CFU/ml of Listeria monocytogenes was dipped for 15 min in sterile water (control) and in 8, 10, or 12% trisodium phosphate (TSP) solutions. Skin samples were stored at 2°C for 5 days, with microbial monitoring on days 0, 1, 3, and 5 after treatment. Compared to the water dip, all TSP treatments significantly (P < 0.05) reduced L. monocytogenes populations on chicken skin. The concentration of the TSP was a significant factor in reducing the populations of the bacteria at days 0, 1, 3, and 5 of refrigerated storage. For all sampling times, the best outcomes were attained with the highest TSP concentration studied (12%). Bacterial reductions in counts during the first day of storage were between 1.52 and 2.70 log10 cycles for 8 and 12% TSP-treated samples, respectively. Significantly greater reductions were observed from the third day of refrigerated storage onward. This occurred largely because populations of L. monocytogenes on control samples increased somewhat, but on TSP-treated samples the pathogen remained practically constant. Differences between L. monocytogenes counts in skin samples immersed in water and those treated with TSP ranged from 2.10 (8% TSP-treated samples) and 3.63 (12% TSP-treated samples) log10 cycles on day 5 of storage. These results indicated that TSP is effective against L. monocytogenes in chicken meat, especially after several days of refrigerated storage.

Influence of strain and trisodium phosphate concentration on growth parameters of Listeria monocytogenes in vitro.

The present study was conducted to determine the influence of strain and trisodium phosphate (TSP) concentration in the growth of Listeria monocytogenes in vitro. Three strains (ATCC 11916, 64d, isolated from chicken meat, and M2-5b, a clinical animal isolate) were inoculated in broth with 0, 0.5, 1 and 1.5% (w/v) of TSP. The shortest lag phase and highest maximum rate of growth (mu) were obtained in the presence of 0.5% TSP. In contrast, the highest lag phase and lowest mu were obtained with 1.5% TSP. For each TSP concentration, significant differences (P < 0.05) in lag phase and mu of the three L. monocytogenes strains were observed. The behaviour of L. monocytogenes is significantly influenced by both the origin of the strain and the salt concentration. Our results indicate the importance of choosing an adequate TSP concentration for the decontamination of foods, because low concentrations could favour the growth of L. monocytogenes.

Trisodium Phosphate Increases Sensitivity of Gram-Negative Bacteria to Lysozyme and Nisin

Cell suspensions of Campylobacter jejuni, Escherichia coli, Pseudomonas fluorescens, and Salmonella enteritidis exposed to sublethal concentrations (0.5 to 5 mM) of trisodium phosphate (TSP) for 10 min showed greatly increased susceptibility to lysozyme (10 μg ml−1) and/or nisin (1 μM). Under optimal conditions at 37°C, reductions in viable count after 30 min were up to six log cycles. At 4°C, C. jejuni showed greater resistance than at 37°C, and maximal cell kills (95%) were reduced by more than two log cycles. Cells dried on the surface of chicken skin were more resistant than suspended cells to TSP–lysozyme and TSP–nisin treatments; nevertheless, at 37°C, kills varied from approximately 95% for S. enteritidis cells with nisin (30 μM) or lysozyme (100 μg ml−1) to >99.9% for C. jejuni and E. coli cells with nisin. Under the experimental conditions used, nisin also reduced viable counts of skin-attached Staphylococcus aureus by >99.9%. The results suggest that the high TSP concentrations (approximately 10% wt/vol, 0.25 M) needed for successful decontamination of gram-negative bacteria, on the surface of poultry and other foodstuffs, may be substantially reduced by following TSP treatment with exposure to low lysozyme or nisin concentrations.

The determination of efficacy of antimicrobial rinses on turkey carcasses using response surface designs

Chlorine, lactic acid, TSP (trisodium phosphate) and a commercial phosphate blend (Avgard TM) were evaluated for their potential bactericidal effects on faecally contaminated turkey carcasses. Carcasses were sprayed for 10 s with each bactericide, at various concentrations and pressure combinations, derived from a response surface central composite design. For all the bactericides, variation in pressure had no significant ( P . 0.05) effect in reducing either total or coliform counts. Lactic acid at various concentrations showed a significant effect ( P < 0.20) in reducing total and coliform counts. The results indicate that lactic acid at 4.25% ( w w ) has the potential for reducing the total microbial load and coliforms by more than 95%. Chlorine, TSP and Avgard TM concentration did not significantly (P > 0.20) affect the microbial load when compared with a water spray, i.e. no bactericide. Preliminary presumptive testing indicated that lactic acid and Avgard TM had some effect against Salmonella spp. Chlorine and TSP, irrespective of concentration and pressure, were not effective against Salmonella spp. Overall, these findings suggest that lactic acid was the most effective bactericide for reducing microbial contamination and improving the safety of poultry meat.