Heat Resistance of Clostridium botulinum Type G in Phosphate Buffer

1984 ◽  
Vol 47 (6) ◽  
pp. 463-466 ◽  
Author(s):  
RICHARD K. LYNT ◽  
HAIM M. SOLOMON ◽  
DONALD A. KAUTTER
Keyword(s):  
Heat Resistance ◽  
Phosphate Buffer ◽  
Clostridium Botulinum ◽  
Thermal Destruction ◽  
Probability Method ◽  
Heat Resistant ◽  
Death Time ◽  
Heat Labile ◽  
Botulinum Type ◽  
D Values

The heat resistance of two strains of Clostridium botulinum type G in phosphate buffer was studied by the thermal death time (TDT) tube method and the thermal destruction rate (TDR) method. The strains were estimated to have one highly heat-resistant spore among approximately 100 spores or 10,000 relatively heat-labile spores. The heat-labile spores were studied by the TDR method and the heat-resistant spores by the TDT tube method. Decimal reduction times (D) for the heat-labile spores were determined by the slopes of the survivor curves. D values for strain 89 ranged from 0.6 min at 190°F to 6.9 min at 170°F and for strain 2739 from 0.9 min at 200°F to 5.9 min at 180°F. Thermal destruction curves for the heat-labile spores gave z values of 24.0 and 17.5 for two spore stocks of strain 89 and 26.0 for strain 2739. D values for the heat-resistant spores, calculated from the combined data of replicate experiments by the Schmidt probability method, ranged from 0.29 min at 240°F to 1.51 min at 210°F for strain 89 and from 0.25 min at 240°F to 1.48 min at 210°F for strain 2739. Extrapolated to 250°F, the thermal destruction curves of the heat-resistant spores gave D250 values of 0.14 to 0.19 min. The thermal destruction curves of the heat-resistant spores were very flat, however, with z values of 37.9 and 49.1 for the two spore stocks of strain 89 and 37.7 for strain 2739. Low-acid canned food processes will provide the same margin of safety for type G as for other proteolytic strains of C. botulinum but ultra high processing temperatures probably will not.

Thermal Resistance of Nonproteolytic Type B and Type E Clostridium botulinum Spores in Phosphate Buffer and Turkey Slurry†

1995 ◽  
Vol 58 (7) ◽  
pp. 758-763 ◽  
Author(s):  
VIJAY K. JUNEJA ◽  
BRIAN S. EBLEN ◽  
BENNE S. MARMER ◽  
AARON C. WILLIAMS ◽  
SAMUEL A. PALUMBO ◽  
...  
Keyword(s):  
Heat Resistance ◽  
Phosphate Buffer ◽  
Clostridium Botulinum ◽  
Thermal Processes ◽  
Type B ◽  
Concomitant Increase ◽  
Death Time ◽  
Thermal Death ◽  
D Values ◽  
Thermal Death Time

The heat resistance of nonproteolytic type B and type E Clostridium botulinum spores in phosphate buffer and turkey slurry was determined from 70 to 90°C. Thermal-death times were determined in vials heated using a water bath. Recovery of heat-injured spores was on reinforced clostridial medium (RCM) and tryptic soy agar (TSA) with and without added lysozyme (10 μg/ml). Decimal-reduction times (D-values) were determined by fitting a survival model to the data using a curve-fitting program. The apparent or measured heat resistance was maximum with RCM supplemented with lysozyme. The D-values at 80°C for type E spores in buffer ranged from 1.03 min for strain Whitefish to 4.51 min for strain Saratoga. The D-value for the most heat-resistant nonproteolytic type B strain KAP B5 in buffer was 4.31 min at 80°C. The z-values in buffer for all strains were very similar, ranging from 8.35 to 10.08°C.Turkey slurry offered protection to the spores with a concomitant increase in heat resistance. The D-values in turkey slurry ranged from 51.89 min at 70°C to 1.18min at 85°C for type E strain Alaska (z = 9.90°C) and from 32.53 min at 75°C to 0.80 min at 90°C for nonproteolytic type B strain KAP B5 (z = 9.43°C). Thermal-death-time values from this study will assist food processors to design thermal processes that ensure safety against nonproteolytic C. botulinum in cook/chill foods.

Heat Resistance of Clostridium botulinum Type B Spores Grown from Isolates from Commercially Canned Mushrooms1

1978 ◽  
Vol 41 (5) ◽  
pp. 351-353 ◽  
Author(s):  
THERON E. ODLAUG ◽  
IRVING J. PFLUG ◽  
DONALD A. KAUTTER
Keyword(s):  
Heat Resistance ◽  
Phosphate Buffer ◽  
Clostridium Botulinum ◽  
Type B ◽  
Botulinum Type ◽  
C Value ◽  
The Mean ◽  
D Values

The heat resistance of ten Clostridium botulinum type B spore crops was determined in mushroom puree and 0.067M Sorenson phosphate buffer (pH 7). The spore crops were grown from Clostridium botulinum isolates obtained from commercially canned mushrooms. The D-values for all of the C. botulinum spore crops were overall slightly higher in the buffer than in mushroom puree. The mean D(110.0 C)-value for the ten spore crops in buffer was 1.17 min and for the spores in mushroom puree the mean D(110.0 C)-value was 0.78 min. The mean D(115.6 C)-value in buffer for the ten spore crops was 0.24 min compared to a mean D(115.6 C)-value of 0.19 min for spores in mushroom puree. The C. botulinum type B spores tested in this study had a heat resistance that was less than the classical heat resistance for C. botulinum spores.

Influence of Sodium Chloride on Thermal Inactivation and Recovery of Nonproteolytic Clostridium botulinum Type B Strain KAP B5 Spores†

1995 ◽  
Vol 58 (7) ◽  
pp. 813-816 ◽  
Author(s):  
VIJAY K. JUNEJA ◽  
BRIAN S. EBLEN
Keyword(s):  
Sodium Chloride ◽  
Heat Resistance ◽  
Clostridium Botulinum ◽  
Thermal Inactivation ◽  
Type B ◽  
Botulinum Type ◽  
Survival And Growth ◽  
Reduced Salt ◽  
D Values ◽  
Recovery Medium

Demand for minimally processed refrigerated foods with reduced salt levels has stimulated renewed interest in the potential for survival and growth of psychrotrophic, nonproteolytic Clostridium botulinum type B spores. As part of a project to better define food-processing requirements, the heat resistance (75 to 90°C) of nonproteolytic C. botulinum type B spores was assessed in turkey containing 1 to 3% (wt/vol) salt (sodium chloride). Heated spores were recovered both on reinforced clostridial medium (RCM) with lysozyme and on RCM having the same salt levels as the heating menstruum. When the recovery medium contained no salt, D-values in turkey slurry containing 1% salt were 42.1, 17.1, 7.8, and 1.1 min at 75, 80, 85, and 90°C, respectively. Increasing levels (2 and 3%, wt/vol) of salt in the turkey slurry reduced the heat resistance as evidenced by reduced spore D-values. Also, apparent or measured heat resistance was decreased with increasing salt concentration in the heating menstruum and the recovery medium. The z-values in turkey slurry for all treatments were similar, ranging from 8.47 10 10.08°C.These data will assist food processors to design thermal processes that ensure safety against nonproteolytic C. botulinum type B spores in cook/chill foods while minimizing quality losses.

Heat Resistance of Fungi Isolated from Frozen Blueberries

2008 ◽  
Vol 71 (10) ◽  
pp. 2030-2035 ◽  
Author(s):  
YUTAKA KIKOKU ◽  
NOBUHIRO TAGASHIRA ◽  
HIROYUKI NAKANO
Keyword(s):  
Thermal Resistance ◽  
Heat Resistance ◽  
Thermal Inactivation ◽  
Heat Resistant ◽  
Death Time ◽  
Naturally Occurring ◽  
Thermal Death ◽  
D Values ◽  
Thermal Death Time

This study dealt with the isolation, characterization, and identification of the fungal microflora of frozen blueberries imported from Canada. The thermal inactivation rates of the rarely studied isolated heat-resistant molds, Devriesia spp. and Hamigera striata, in naturally and artificially contaminated blueberry slurries were also determined. The D-values of naturally contaminating Devriesia spp. at 70, 80, 85, and 90°C were 714, 114, 44.4, and 14.1 min, respectively. The D-values of H. striata at 70, 80, 85, and 90°C were 909, 286, 42.6, and 10.3 min, respectively. The z-values calculated from the thermal death time curves were 11.0 and 6.9°C for Devriesia spp. and H. striata, respectively. Results also showed that in both test mold species, the naturally occurring molds had significantly higher thermal resistance than did the artificially contaminated counterparts. The results established by this study may be used by blueberry processors to prevent losses due to spoilage caused by the heat-resistant microorganisms.

Heat Resistance of Juice Spoilage Microorganisms

2002 ◽  
Vol 65 (8) ◽  
pp. 1271-1275 ◽  
Author(s):  
ADRIENNE E. H. SHEARER ◽  
ALEJANDRO S. MAZZOTTA ◽  
ROLENDA CHUYATE ◽  
DAVID E. GOMBAS
Keyword(s):  
Heat Resistance ◽  
Process Conditions ◽  
Citrate Buffer ◽  
Ph Values ◽  
Death Time ◽  
High Fructose ◽  
Thermal Death ◽  
Challenge Tests ◽  
D Values ◽  
Thermal Death Time

The heat resistance of various yeasts (Saccharomyces cerevisiae, Rhodotorula mucilaginosa, Torulaspora delbrueckii, and Zygosaccharomyces rouxii), molds (Penicillium citrinum, Penicillium roquefortii, and Aspergillus niger), and lactic acid bacteria (Lactobacillus fermentum and Lactobacillus plantarum) obtained from spoiled acid or acidified food products was determined in 0.1 M citrate buffer at pH values of 3.0, 3.5, and 4.0. S. cerevisiae was the most heat resistant of the microorganisms in citrate buffer, and its heat resistance was further evaluated in apple, grapefruit, calcium-fortified apple, and tomato juices as well as in a juice base with high fructose corn syrup. Decimal reduction times (D-values) and changes in temperature required to change the D-value (z-values) for S. cerevisiae were higher in the juices than in citrate buffer at all pH values tested. The D57°C(135°F)-values varied from 9.4 min in the juice product with pH 2.8 to 32 min in a calcium-added apple juice with pH 3.9. The S. cerevisiae strain used in this study can be used in thermal-death-time experiments in acidic products to calculate process conditions and in challenge tests to validate the calculated temperatures and hold times during processing.

scholarly journals Inactivation of non-proteolytic Clostridium botulinum type E in low-acid foods and phosphate buffer by heat and pressure

PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0200102 ◽  
Author(s):  
Maximilian B. Maier ◽  
Tobias Schweiger ◽  
Christian A. Lenz ◽  
Rudi F. Vogel
Keyword(s):  
Phosphate Buffer ◽  
Clostridium Botulinum ◽  
Botulinum Type ◽  
Clostridium Botulinum Type E

The Heat Resistance of Spores of Clostridium botulinum 213B Heated at 121–130°C in Acidified Mushroom Extract

1992 ◽  
Vol 55 (11) ◽  
pp. 913-915 ◽  
Author(s):  
K. L. BROWN ◽  
A. MARTINEZ
Keyword(s):  
Citric Acid ◽  
Thermal Resistance ◽  
Heat Resistance ◽  
High Temperatures ◽  
Clostridium Botulinum ◽  
Mushroom Extract ◽  
D Values

Spores of Clostridium botulinum 213B were heated in mushroom extract acidified to pH 6 with citric acid or glucono-deltalactone at temperatures of 121.1, 125, and 130°C using a thermoresistometer. Decimal reduction times were similar in acidified and natural pH (6.7) mushroom extract. At 121.1, 125, and 130°C, D values were in the range 2.44 – 2.55 s, 0.91–1.45 s, and 0.51–0.75 s, respectively. There was no evidence that mild acidification reduced thermal resistance at high temperatures.

Combined High Pressure and Thermal Processing on Inactivation of Type A and Proteolytic Type B Spores of Clostridium botulinum

2013 ◽  
Vol 76 (8) ◽  
pp. 1384-1392 ◽  
Author(s):  
N. RUKMA REDDY ◽  
KRISTIN M. MARSHALL ◽  
TRAVIS R. MORRISSEY ◽  
VIVIANA LOEZA ◽  
EDUARDO PATAZCA ◽  
...  
Keyword(s):  
High Pressure ◽  
Thermal Processing ◽  
Clostridium Botulinum ◽  
High Pressures ◽  
Type A ◽  
Test System ◽  
High Pressure Processing ◽  
Type B ◽  
Botulinum Type ◽  
D Values

The aim of this study was to determine the resistance of multiple strains of Clostridium botulinum type A and proteolytic type B spores exposed to combined high pressure and thermal processing and compare their resistance with Clostridium sporogenes PA3679 and Bacillus amyloliquefaciens TMW-2.479-Fad-82 spores. The resistance of spores suspended in N-(2-acetamido)-2-aminoethanesulfonic acid (ACES) buffer (0.05 M, pH 7.0) was determined at a process temperature of 105°C, with high pressures of 600, 700, and 750 MPa by using a laboratory-scale pressure test system. No surviving spores of the proteolytic B strains were detected after processing at 105°C and 700 MPa for 6 min. A >7-log reduction of B. amyloliquefaciens spores was observed when processed for 4 min at 105°C and 700 MPa. D-values at 105°C and 700 MPa for type A strains ranged from 0.57 to 2.28 min. C. sporogenes PA3679 had a D-value of 1.48 min at 105°C and 700 MPa. Spores of the six type A strains with high D-values along with C. sporogenes PA3679 and B. amyloliquefaciens were further evaluated for their pressure resistance at pressures 600 and 750 MPa at 105°C. As the process pressure increased from 600 to 750 MPa at 105°C, D-values of some C. botulinum strains and C. sporogenes PA3679 spores decreased (i.e., 69-A, 1.91 to 1.33 min and PA3679, 2.35 to 1.29 min). Some C. botulinum type A strains were more resistant than C. sporogenes PA3679 and B. amyloliquefaciens to combined high pressure and heat, based on D-values determined at 105°C. Pulsed-field gel electrophoresis (PFGE) was also performed to establish whether strains with a similar restriction banding pattern also exhibited similar D-values. However, no correlation between the genomic background of a strain and its resistance to high pressure processing was observed, based on PFGE analysis. Spores of proteolytic type B strains of C. botulinum were less resistant to combined high pressure and heat (700 MPa and 105°C) treatment when compared with spores of type A strains.

FACTORS IN SURVIVAL OF CLOSTRIDIUM BOTULINUM TYPE E SPORES THROUGH THE FISH SMOKING PROCESS

1972 ◽  
Vol 35 (3) ◽  
pp. 163-166 ◽  
Author(s):  
G. G. Alderman ◽  
Gretchen J. King ◽  
H. Sugiyama
Keyword(s):  
Clostridium Botulinum ◽  
Heat Processing ◽  
High Moisture ◽  
Death Time ◽  
Thermal Death ◽  
Botulinum Type ◽  
Clostridium Botulinum Type E ◽  
Raw Fish ◽  
Fish Mince ◽  
Thermal Death Time

Fish, experimentally inoculated with 1 ×106 Clostridium botulinum type E spores, were given heat treatments equivalent to those used in commercial smoking (180 F for 30 min following come-up time of 2.5 – 3 hr). The percentages of such fish containing viable type E spores were significantly lower among fish heated in an environment of high moisture than among those heated in atmospheres of low moisture. Type E spores heated in raw fish mince were more heat resistant than those heated in mince that was previously autoclaved. A similar difference was observed for spores in raw and cooked egg white, another substrate which coagulates rapidly at the temperature of thermal death time studies (82.5 C). Spores in the drippings of fish hung for heating survived heat processing and could be a source of cross contamination.

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