Mycotoxin Bioassay, Using Bacillus stearothermophilus

1975 ◽  
Vol 58 (3) ◽  
pp. 624-625
Author(s):  
Jürgen Reiss
Keyword(s):  
Nutrient Solution ◽  
Bacillus Stearothermophilus ◽  
Color Change ◽  
Bromocresol Purple ◽  
Ph Indicator

Abstract Spores of Bacillus stearothermophilus in standardized spore strips are pretreated with solutions of the mycotoxins aflatoxin Bl, patulin, rubratoxin B, and diacetoxyscirpenol and subsequently incubated in a nutrient solution containing bromocresol purple as pH indicator. After 16.5 hr of incubation the color of the indicator medium inoculated with untreated spore strips of B. stearothermophilus changes from purple to yellow; no color change occurs in the indicator medium inoculated with spore strips treated 15 min with 0.01 μg of any of the 4 mycotoxins/ml during a 60 hr incubation.

scholarly journals Standardization of Neisseria meningitidis Serogroup B Colorimetric Serum Bactericida Assay

2002 ◽  
Vol 9 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Tamara Rodríguez ◽  
Miriam Lastre ◽  
Barbara Cedré ◽  
Judith del Campo ◽  
Gustavo Bracho ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Target Cell ◽  
Color Change ◽  
Cell Number ◽  
Target Cells ◽  
Bromocresol Purple ◽  
Ph Indicator ◽  
Significant Difference ◽  
Mueller Hinton Agar ◽  
Group B

ABSTRACT The correlate of protection for serogroup B meningococci is not currently known, but for serogroup C it is believed to be the serum bactericidal assay (SBA). The current SBAs are labor intensive and the variations in protocols among different laboratories make interpretation of results difficult. A colorimetric SBA (cSBA), based on the ability of Neisseria meningitidis serogroup B to consume glucose, leading to acid production, was standardized by using group B strain Cu385-83 as the target. The cSBA results were compared to those obtained for a traditional colony-counting microassay (mSBA). Glucose and bromocresol purple pH indicator were added to the medium in order to estimate growth of cSBA target cell survivors through color change. Different variants of the assay parameters were optimized: growth of target cells (Mueller Hinton agar plates), target cell number (100 CFU/per well), and human complement source used at a final concentration of 25%. After the optimization, three other group B strains (H44/76, 490/91, and 511/91) were used as targets for the cSBA. The selection of the assay parameters and the standardization of cSBA were done with 13 sera from vaccinated volunteers. The titers were determined as the higher serum dilution that totally inhibited the bacterial growth marked by the color invariability of the pH indicator. This was detected visually as well as spectrophotometrically and was closely related to a significant difference in the growth of target cell survivors determined using Student’s t test. Intralaboratory reproducibility was ±1 dilution. The correlation between bactericidal median titers and specific immunoglobulin G serum concentration by enzyme immunoassay was high (r = 0.910, P < 0.01). The bactericidal titers generated by the cSBA and the mSBA were nearly identical, and there was a high correlation between the two assays (r = 0.974, P < 0.01). The standardized cSBA allows easy, fast, and efficient evaluation of samples.

scholarly journals Pengembangan Label Pintar untuk Indikator Kesegaran Daging Sapi pada Kemasan

2018 ◽  
Vol 6 (2) ◽  
pp. 199
Author(s):  
Arjun Nurfawaidi ◽  
Bambang Kuswandi ◽  
Lestyo Wulandari
Keyword(s):  
Room Temperature ◽  
Color Change ◽  
Bromocresol Purple ◽  
Methyl Red ◽  
Ph Indicator ◽  
The Mean ◽  
Ph Increase ◽  
Smart Label ◽  
Imagej Software ◽  
Color Indicator

  Meat is a high nutritional food that rich of protein, fat, and sugar. Smart label has been applied as a beef freshness detector. Two types of pH indicator have been used i.e bromocresol purple (BCP) and methyl red (MR) as dual indicator freshness. The objective of this research was to determine the beef freshness using smart label at room temperature. The color change of the smart label was examined by imageJ software to determine the freshness degree using the mean RGB value. The beef was examined every 2 hours for pH and total volatile base (TVB-N) analysis during the 24 hours storage at room temperature. The result showed that color indicator will change according to the beef freshness, bromocresol purple turned from yellow to purple (mean RGB 171.465 ± 1.122) and methyl red turned from red to yellow (mean RGB 162.082 ± 1.315). The beef freshness at room temperature decreased as the pH increase from 5.61 to 6.23 along with the color change of smart label. Furthermore, the color would change when 0.022 %N of TVB-N has been reached. Therefore, the beef freshness can be determined by using smart label based on dual indicator of bromocresol purple and methyl red in room temperature.   Keywords: beef freshness, smart label, pH, TVB  

scholarly journals Rapid Aminoglycoside NP Test for Rapid Detection of Multiple Aminoglycoside Resistance in Enterobacteriaceae

2017 ◽  
Vol 55 (4) ◽  
pp. 1074-1079 ◽  
Author(s):  
Patrice Nordmann ◽  
Aurélie Jayol ◽  
Jan Dobias ◽  
Laurent Poirel
Keyword(s):  
Glucose Metabolism ◽  
Gold Standard ◽  
Rapid Detection ◽  
Color Change ◽  
Dilution Method ◽  
Ph Indicator ◽  
Aminoglycoside Resistance ◽  
Content Type ◽  
Acid Metabolites ◽  
Broth Dilution

ABSTRACTThe rapid aminoglycoside NP (Nordmann/Poirel) test was developed to rapidly identify multiple aminoglycoside (AG) resistance inEnterobacteriaceae. It is based on the detection of the glucose metabolism related to enterobacterial growth in the presence of a defined concentration of amikacin plus gentamicin. Formation of acid metabolites was evidenced by a color change (orange to yellow) of the red phenol pH indicator. The rapid aminoglycoside NP test was evaluated by using bacterial colonies of 18 AG-resistant isolates producing 16S rRNA methylases, 20 AG-resistant isolates expressing AG-modifying enzymes (acetyl-, adenyl-, and phosphotransferases), and 10 isolates susceptible to AG. Its sensitivity and specificity were 100% and 97%, respectively, compared to the broth dilution method, which was taken as the gold standard for determining aminoglycoside resistance. The test is inexpensive, rapid (<2 h), and implementable worldwide.

scholarly journals Rapid Detection of Fosfomycin Resistance in Escherichia coli

2018 ◽  
Vol 57 (1) ◽  
Author(s):  
Patrice Nordmann ◽  
Laurent Poirel ◽  
Linda Mueller
Keyword(s):  
Escherichia Coli ◽  
Bacterial Growth ◽  
Test Performance ◽  
Color Change ◽  
Ph Indicator ◽  
Content Type ◽  
E Coli ◽  
Yellow Color ◽  
Fosfomycin Resistance ◽  
User Friendly

ABSTRACT The rapid fosfomycin/Escherichia coli NP test was developed to detect fosfomycin resistance in E. coli isolates. The test is based on glucose metabolization and the detection of bacterial growth in the presence of fosfomycin at 40 µg/ml. Bacterial growth is visually detectable by an orange-to-yellow color change of red phenol, a pH indicator. A total of 100 E. coli isolates, among which 22 were fosfomycin resistant, were used to evaluate the test performance. The sensitivity and specificity of the test were 100% and 98.7%, respectively. This new test is user friendly, sensitive and specific, and its results are obtained in 1 h 30 min.

Evaluation of a Rapid Readout Biological Indicator for Flash Sterilization with Three Biological Indicators and Three Chemical Indicators

1993 ◽  
Vol 14 (7) ◽  
pp. 390-394 ◽  
Author(s):  
William A. Rutala ◽  
Maria F. Gergen ◽  
David J. Weber
Keyword(s):  
Enzyme Activity ◽  
Bacillus Stearothermophilus ◽  
Color Change ◽  
Safety Margin ◽  
Biological Indicators ◽  
Biological Indicator ◽  
Processing Conditions ◽  
Fluorescent Product ◽  
Chemical Indicators ◽  
Chemical Indicator

AbstractObjective:Flash sterilization is most commonly used for emergency sterilization of unwrapped items in a gravity displacement sterilizer for three minutes. Sterilization quality assurance is monitored by biological indicators that require a 24-hour incubation prior to reading. In this study, we compared a new biological indicator that provides results within 60 minutes with three conventional, 24-hour biological indicators for monitoring flash sterilization and three chemical indicators.Design:Conventional biological indicators tested included the conventional Attest 1261, Proof Flash and Assert, while the rapid readout indicator tested was Attest 1291. Attest Rapid Readout detects the presence of aBacillus stearothermophilusenzyme by reading a fluorescent product that is produced by the enzymatic break-down of a nonfluorescent substrate. Chemical indicators tested included Comply, Incheque, and Thermalog S. Survival at 132°C in a gravity displacement sterilizer was measured by media color change after incubation for 24 hours at 56°C for the three conventional biological indicators, fluorescence at 60 minutes for the Attest Rapid Readout biological indicator, and color change for the chemical indicators. Each exposure time was replicated four times with 10 of each biological and chemical indicator per run.Results:The conventional biological indicators (Attest, Proof Flash, and Assert) had 90%, 48%, and 40% spore survival at two minutes exposure; 23%, 3%, and 0% at three minutes exposure; and 3%, 0%, and 0% at four minutes exposure respectively. The Attest Rapid Readout biological indicator had 88%, 33%, and 0% enzyme activity detectable at 2, 3, and 4 minutes exposure. The chemical indicators Comply, Incheque, and Thermalog S revealed sterilization failure rates of 100%, 100%, and 100% at 0 minutes exposure; 100%, 100%, and 45% at one minute; 0%, 0%, and 28% at two minutes exposure; 0%, 0%, and 18% at three minutes exposure; and 0%, 0%, and 0% at four minutes exposure, respectively.Conclusion:The sensitivity of the Attest Rapid Readout parallels the conventional biological indicators. These data suggest that a 60-minute rapid readout biological indicator is equivalent to the 24-hour biological indicators. If further studies demonstrate that a four-minute flash sterilization cycle provides a needed safety margin to ensure sterilization, then consideration should be given to requiring a four-minute flash sterilization cycle. Chemical indicators were too sensitive to the processing conditions (eg, steam) and are inadequate to ensure adequate sterilization.

scholarly journals Mass spectra of sulfonephthalein pH indicator dyes and their impurities

2017 ◽  
Vol 122 ◽  
Author(s):  
Regina A. Easley ◽  
Benjamin J. Place
Keyword(s):  
Mass Spectrometry ◽  
Bromothymol Blue ◽  
Synthesis Process ◽  
Thymol Blue ◽  
Bromocresol Green ◽  
Bromocresol Purple ◽  
Phenol Red ◽  
Ph Indicator ◽  
Ph Measurements ◽  
Indicator Dyes

Sulfonephthalein pH indicator dyes have historically been noted for impurities originating from the synthesis process, which lead to batch to batch differences in pH measurements. Uncertainties up to 0.1 pH units have been attributed to impurities in these reagents. In an effort to understand the extent of impurities in these dyes and the potential impact on the expanded uncertainty of spectrophotometric pH measurements, we have examined seven commercially available sulfonephthalein pH indicators using liquid chromatography-mass spectrometry (LC-MS): bromocresol green (BCG), bromocresol purple (BCP), bromothymol blue (BTB), cresol red (CR), meta-cresol purple (MCP), phenol red (PR), and thymol blue (TB). Peaks eluting from the LC were subjected to fragmentation by mass spectrometry. The resulting dataset will aid in efforts to improve the synthesis or purification of these dyes.

scholarly journals Synthesis of Intelligent pH Indicative Films from Chitosan/Poly(vinyl alcohol)/Anthocyanin Extracted from Red Cabbage

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1088 ◽  
Author(s):  
Vo ◽  
Dang ◽  
Chen
Keyword(s):  
Tensile Strength ◽  
Vinyl Alcohol ◽  
Color Change ◽  
Sodium Tripolyphosphate ◽  
Poly Vinyl Alcohol ◽  
Ph Indicator ◽  
Red Cabbage ◽  
Cast Films ◽  
Ft Ir ◽  
Pva Hydrogel

In this study, pH indicative films were successfully synthesized from hydrogels made by blending 1% poly(vinyl alcohol) (PVA) and 1% chitosan (CS) with anthocyanin (ATH) and sodium tripolyphosphate (STPP). Particularly, ATH extracted from red cabbage was used as the pH indicator, while STPP was utilized as the cross-linking agent to provide better mechanical properties of the cast films. FT-IR spectra confirmed the existence of the ATH in the cast films. Moreover, the tensile strength, the elongation-at-break, and the swelling indices of the cast films were measured. In general, these properties of pH indicative films were profoundly influenced by the compositions of PVA/CS and the STPP dosage applied in the hydrogels. For example, the tensile strength could change from 43.27 MPa on a film cast from pure PVA hydrogel to 29.89 MPa, if 35% of the PVA hydrogel was substituted with CS. The cast films were applied as a food wrap that could be used to monitor visually the quality of the enwrapped food via the color change of the film upon the variation in pH values of the enwrapped food. In practice, a sequential change in color was successfully observed on the pH indicative films partially enwrapping the pork belly, indicating the spoilage of the meat.

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