Inhibitory Effects of Various Salts and/or Ionic Strengths on Growth from Clostridium botulinum 52A Spores or Vegetative Cells

1985 ◽  
Vol 48 (5) ◽  
pp. 421-428 ◽  
Author(s):  
M. K. WAGNER ◽  
F. F. BUSTA
Keyword(s):  
Ionic Strength ◽  
Clostridium Botulinum ◽  
Potassium Sorbate ◽  
Chloride Salt ◽  
Inhibitory Effects ◽  
Vegetative Cells ◽  
Inhibition Of Growth ◽  
The Mean ◽  
Ph Level ◽  
Peptone Yeast Extract Glucose

Growth response from spores and vegetative cells of Clostridium botulinum strain 52A in peptone-yeast extract-glucose (PYEG) broth at two pH levels (5.55 or 5.85) containing sodium acid pyrophosphate (SAPP) (0, 0.2, 0.4%), NaCl (0, 1.25, 2.50%) and/or potassium sorbate (KS) (0, 0.13, 0.26%) was measured as the mean A630 nm of 20 tubes at 37°C. Additional treatments contained KC1 and MgCl2 (0, 1.25, 2.50%) without SAPP or KS. Growth ratios (GR = treatment/control) based on time to reach A630 = 0.35 were calculated to compare effects of additives on strain 52A. Growth from spores was affected significantly (p≤0.01) by pH level. KS and KS/pH interactions were also significant factors in growth from both spores and vegetative cells; SAPP/pH interactions were significant for cell growth, only. Combinations of SAPP (0.2, 0.4%) NaCl (0%) and KS (0.26%) were the most favorable treatments for delaying growth from spores or vegetative cells. NaCl (1.25, 2.50%) decreased antibotulinal effects produced by combinations of SAPP and KS. Elimination of NaCl enhanced antibotulinal effects. Formulations containing KC1 or MgCl2 (without SAPP and KS) at the same molarity as the NaCl in earlier treatments (0.21, 0.43) resulted in inhibition of growth from vegetative cells greater than growth from spores in the presence of MgCl2 at M = 0.43 (ionic strength = 1.29). This inhibition was more evident at pH 5.55 than pH 5.85. This study in a model system suggests ionic strength and/or chloride salt may be important considerations when manipulating formulations of additives designed to control C. botulinum growth.

Differential Sensitivity of Clostridium botulinum Strains to Nisin is Not Biotype-Associated

1992 ◽  
Vol 55 (6) ◽  
pp. 444-448 ◽  
Author(s):  
THOMAS J. MONTVILLE ◽  
ANN M. ROGERS ◽  
AMECHI OKEREKE
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Plantarum ◽  
Lactococcus Lactis ◽  
Yeast Extract ◽  
Clostridium Botulinum ◽  
Differential Sensitivity ◽  
Vegetative Cells ◽  
Significant Difference ◽  
Peptone Yeast Extract Glucose

The sensitivities of proteolytic and nonproteolytic Clostridium botulinum strains to nisin and other bacteriocins were investigated. Although there were statistically different nisin sensitivities among vegetative cells from 18 C. botulinum strains, these differences were not biotype-associated. When inoculated into tryptose peptone yeast extract glucose broth containing nisin at various levels, spores from strain 56 A were not inhibited at all by 100 IU/ml of nisin. About 2,500 IU/ml was required to inhibit growth for 30 d. In contrast, only 10 IU/ml was required to inhibit strain 169 for 30 d. Both strains were completely inhibited at the 10,000 IU/ml limit allowed in processed cheeses. Spores from strains having limited (strain 56A), moderate (strain 25675), or extreme (strain 169) nisin sensitivity were examined for bacteriocin-mediated inhibition by Lactococcus lactis 11454, Pediococcus pentosaceus 43200, P. pentosaceus 43201, and Lactobacillus plantarum BN using the spot-on-the-lawn method. While the differences in nisin sensitivity were confirmed, there was no statistically significant difference in their sensitivities to the bacteriocins produced by other lactic acid bacteria.

Effect of Sucrose Esters in Combination with Selected Mold Inhibitors on Growth and Aflatoxin Production by Aspergillus parasiticus1

1986 ◽  
Vol 49 (5) ◽  
pp. 378-382 ◽  
Author(s):  
DOUGLAS L. MARSHALL ◽  
LLOYD B. BULLERMAN
Keyword(s):  
Fold Increase ◽  
Aflatoxin Production ◽  
Sucrose Ester ◽  
Potassium Sorbate ◽  
Sucrose Esters ◽  
Inhibitory Effects ◽  
Ph Values ◽  
Inhibition Of Growth ◽  
Calcium Propionate ◽  
Low Levels

The effects of sucrose esterified with a mixture of palmitic and stearic acids (commonly referred to as sucrose ester) in combination with cinnamon, potassium sorbate, or calcium propionate on growth of and aflatoxin production by Aspergillus parasiticus was studied in broths at two pH values. Cinnamon in combination with sucrose ester did not result in additive or synergistic inhibitory effects on growth or aflatoxin production. At pH 4.0, subinhibitory amounts of cinnamon were stimulatory toward growth and antagonistic to inhibition of growth by sucrose ester. Complete inhibition of growth and aflatoxin production was observed with a cinnamon level of 1.0%, alone and in combination with sucrose ester. Low levels (0.1%) of calcium propionate or potassium sorbate combined with sucrose ester did not enhance inhibition of growth or aflatoxin production. A synergistic effect on inhibition of growth was observed with high levels of propionate or sorbate in combination with sucrose ester, while aflatoxin production remained relatively unaffected. However, subinhibitory levels of propionate resulted in a 10-fold increase of aflatoxin production and a shift in the ratio of aflatoxin B1 and G1, from 1:1 to 1:8. Subinhibitory levels of sorbate also caused a stimulation of aflatoxin production during the latter stages of incubation, though to a lesser degree than propionate.

Potassium Sorbate Inhibition of Microorganisms Isolated from Seafood1

1982 ◽  
Vol 45 (14) ◽  
pp. 1310-1313 ◽  
Author(s):  
YUH-MEI CHUNG ◽  
J. S. LEE
Keyword(s):  
Inhibitory Concentration ◽  
Basal Medium ◽  
Inhibitory Effect ◽  
Potassium Sorbate ◽  
Inhibitory Effects ◽  
Freeze Thaw ◽  
Inhibition Of Growth ◽  
Heat Treated ◽  
Lag Period ◽  
Logarithmic Growth

Microorganisms isolated from seafood showed various degrees of sensitivity toward potassium sorbate (PS). At pH 7.0, PS concentration of 0.53% completely inhibited growth of Moraxella sp., while 2.73% was needed to inhibit Arthrobacter sp. Pseudomonas I sp., which was relatively resistant to PS (inhibitory concentration = 1.62%), was not affected by 0.3% PS after freeze-thaw treatment (−78°C for 8 min and 20°C for 20 min), but showed a delay in onset of logarithmic growth for up to 20 h after heating at 50°C for 5 min. The inhibitory effect of PS on sub-lethally injured Pseudomonas I was greater in basal medium (Minimum Broth, Davis) than in a rich medium (tryptone-peptone-extract, TPE). Alteromonas putrefaciens, which was sensitive to PS (inhibitory concentration = 0.74%), was also sensitive to freeze-thaw and mild heat. The lag period for quick-frozen cells was extended by 14 h in the presence of 0.05% PS. Heating at 45°C for 10 sec was sufficient to cause complete inhibition of growth by 0.05% PS in MBD, and 8 h delay in the onset of logarithmic growth in TPE. Selective and inhibitory effects of PS, therefore, could be further enhanced in frozen or heat-treated seafood.

SERUM TRIIODOTHYRONINE DETERMINATION BY SATURATION ANALYSIS

1973 ◽  
Vol 72 (4) ◽  
pp. 714-726 ◽  
Author(s):  
A. Burger ◽  
B. Miller ◽  
C. Sakoloff ◽  
M. B. Vallotton
Keyword(s):  
Ionic Strength ◽  
Limit Of Detection ◽  
Improved Method ◽  
Accuracy Of Measurement ◽  
Tracer Amount ◽  
The Mean ◽  
Physiological Values ◽  
Hyperthyroid Patients ◽  
Solvent Blank

ABSTRACT An improved method for the determination of serum triiodothyronine (T3) has been developed. After addition of a tracer amount of the hormone, T3 was extracted from 1 ml serum under conditions of pH and ionic strength which favoured T3 extraction (89%) over thyroxine (T4) extraction (58%). Chromatography of the extracted material on Sephadex LH-20 separated T3 completely from residual T4. The T3 eluate was dried, then re-dissolved in 0.5 ml NaOH 0.04 n. To 0.2 ml duplicate aliquots, a standard amount of TBG was added for the competitive protein analysis. After one hour incubation at 4°C, separation of bound from free T3 was achieved on small Sephadex G-25 columns. Overall recovery was 67 ± 10.8% and correction for the loss was made. The solvent blank was 37 ± 27 (sd) ng/100 ml. Accuracy of measurement of known quantities of T3 added to serum was 98.4%. The coefficient of variation within the assay was 6.2% and between the assays it was 11.4%. The limit of detection (0.1 ng) corresponded to a concentration of 25 ng/100 ml. T4 added to serum did not interfere with T3 determination until high non-physiological values were reached. The mean ± sd serum T3 in 54 euthyroid subjects was 153 ± 58 ng/100 ml and in 24 hyperthyroid patients it was 428 ±186 ng/100 ml; 4 out of the 24 hyperthyroid values were within 2 sd of the mean euthyroid group. All the values found in the euthyroid group were well above the limit of detection of the method.

Fate of Selected Pathogens Inoculated into Foods Prepared in Slow Cookers1,2

1979 ◽  
Vol 42 (11) ◽  
pp. 872-876 ◽  
Author(s):  
J. RITTER ◽  
J. O'LEARY ◽  
B. E. LANGLOIS
Keyword(s):  
Staphylococcus Aureus ◽  
Low Temperature ◽  
Salmonella Typhimurium ◽  
Clostridium Perfringens ◽  
Health Hazard ◽  
Green Bean ◽  
Vegetative Cells ◽  
Salmonella Choleraesuis ◽  
Navy Beans ◽  
The Mean

Staphylococcus aureus, Clostridium perfringens. Salmonella choleraesuis, and Salmonella typhimurium were inoculated (108 cells or spores) into two slow cookers containing green bean casserole, baked navy beans, chicken cacciatore, barbecued ribs or pork pot roast, and their fate determined after cooking. Heating patterns also were determined at three positions inside the two cookers. None of the foods cooked in either of the slow cookers contained detectable levels of S. aureus or salmonellae. The similarity between C. perfringens vegetative and spore counts indicate that only spores were present in the cooked foods. Except for the green bean casserole cooked using a low temperature setting, cooking resulted in a 0.44–1.67 and 0.36–1.54 log count reduction, respectively, of vegetative cells and spores of C. perfringens. Counts of vegetative cells and spores after cooking the green bean casserole were approximately .18 and .30 log counts higher than the uncooked counts. The mean times for the coldest areas in Cooker A to reach 50 C were 2.57 and 0.97 h, respectively, for the low (80 watts) and high (160 watts) temperature settings. The mean times for the coldest areas in Cooker B (removable liner) to reach 50 C were 2.35 and 0.52 h for the low (130 watts) and high (260 watts) temperature settings, respectively. Results suggest that when the recommended quantities of ingredients are used and the proper cooking procedure followed, foods prepared in the slow cookers studied do not present a health hazard.

Hop Bract Polyphenols Reduced Three-day Dental Plaque Regrowth

2007 ◽  
Vol 86 (9) ◽  
pp. 848-851 ◽  
Author(s):  
K. Shinada ◽  
M. Tagashira ◽  
H. Watanabe ◽  
P. Sopapornamorn ◽  
A. Kanayama ◽  
...  
Keyword(s):  
Clinical Study ◽  
Oral Hygiene ◽  
Dental Plaque ◽  
Mutans Streptococci ◽  
Healthy Male ◽  
Inhibitory Effects ◽  
Performance Score ◽  
Double Blind ◽  
The Mean

Previous research has shown the inhibitory effects of hop bract polyphenols (HBP) on cariogenic streptococci in vitro, but their effects in humans have not been investigated. This double-blind, crossover clinical study tested the hypothesis that HBP delivered in a mouthrinse suppresses plaque regrowth in humans. Twenty-nine healthy male volunteers had all plaque removed, and refrained from all oral hygiene for 3 days, except for rinsing with a mouthrinse containing 0.1% HBP or a placebo. The results showed that the mean amount of plaque assessed by the Patient Hygiene Performance score after the volunteers used the HBP mouthrinse was significantly less than that after they used the placebo (p < 0.001). The number of mutans streptococci in the plaque samples after volunteers used the HBP mouthrinse was significantly lower than that after they used the placebo (p < 0.05). These findings suggested that HBP, delivered in a mouthrinse, successfully reduced dental plaque regrowth in humans.

Association of [32P] with Clostridium botulinum 52A Vegetative Cells Following Growth in a Medium Containing Sodium Dihydrogen [32P]-Pyrophosphate

1986 ◽  
Vol 49 (5) ◽  
pp. 352-354 ◽  
Author(s):  
M. K. WAGNER ◽  
F. F. BUSTA
Keyword(s):  
Stationary Phase ◽  
Clostridium Botulinum ◽  
Cellular Growth ◽  
Vegetative Cells ◽  
Sodium Dihydrogen ◽  
Logarithmic Growth

The association of [32P] with Clostridium botulinum 52A vegetative cells following growth in a medium containing either sodium dihydrogen [32P]-pyrophosphate ([32P]-SAPP) or sodium dihydrogen [32P]-orthophosphate ([32P]-orthophosphate) was studied. Absorbency measurements at 630 nm were used in addition to [32P] recovery in determining [32P] association with cellular growth and metabolism. Radiolabeling experiments showed [32P]-orthophosphate was associated with vegetative cells during logarithmic growth, yet was released once stationary phase was attained or upon lysis. [3P]-SAPP was also associated with cells during growth, but was not released once stationary phase was attained. Results suggested [32P]-SAPP continued to bind cells or other metabolic materials following attainment of the stationary phase of cells. Fractionation of 24 and 48 h-old cultures grown in the presence of [32P]-SAPP showed a higher percentage of [32P] associated with the RNA fraction (3.91 and 2.48%, respectively) compared to the DNA fraction (0.09 and 0.07%, respectively).

Inhibition of Clostridium botulinum Okra B by N-Acyl Amino Acid Ester (Nα-Cocoil Arginine Ethylester•DL-Pyrrolidone Carbonate)

1984 ◽  
Vol 47 (4) ◽  
pp. 303-304 ◽  
Author(s):  
MISAO MIWA ◽  
TAKESHI MORI ◽  
SHINJI MATSUURA
Keyword(s):  
Amino Acid ◽  
Yeast Extract ◽  
Acid Ester ◽  
Clostridium Botulinum ◽  
Toxin Production ◽  
Amino Acid Ester ◽  
Medium Ph ◽  
Peptone Yeast Extract Glucose

An amino acid ester, Nα-cocoil-L-arginine ethylester·DL-pyrrolidone carbonate (CAE), was inhibitory to growth and toxin production of Clostridium botulinum okra in peptone-yeast extract-glucose (PYG) medium, pH 7.0, at 30°C. Addition of 10 mg of CAE/L to PYG medium delayed toxin production and 25 mg of CAE/L inhibited growth and toxin production, whereas 5 mg of CAE/L had no effect on both growth and toxin production.

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