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 Spores of Non-Proteolytic Type B Clostridium botulinum

1982 ◽  
Vol 45 (10) ◽  
pp. 909-912 ◽  
Author(s):  
VIRGINIA N. SCOTT ◽  
DANE T. BERNARD
Keyword(s):  
Liquid Phase ◽  
Heat Resistance ◽  
Clostridium Botulinum ◽  
Beef Heart ◽  
Regression Analyses ◽  
Type B ◽  
Death Time ◽  
Thermal Death ◽  
Biphasic Medium ◽  
Thermal Death Time

The heat resistance of spores of non-proteolytic type B Clostridium botulinum was compared to that of type E and proteolytic type B spores. Spore suspensions were produced in a biphasic medium consisting of beef heart agar overlaid with a liquid phase containing trypticase, peptone, glucose, starch and cysteine. Thermal death time curves were established for seven strains heated in phosphate buffer. In general, spore suspensions of non-proteolytic type B strains had greater thermal resistance than type E strains. Decimal reduction times at 82.2°C, established by linear regression analyses of data, ranged from 1.49 to 32.3 min, but the higher heat resistances were not obtained consistently, even with different spore suspensions of the same strain. None of the spore suspensions of non-proteolytic, type B C. botulinum demonstrated heat resistance comparable to that of the proteolytic type B spores.

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.

Heat Resistance of an Outbreak Strain of Listeria monocytogenes in Hot Dog Batter

2001 ◽  
Vol 64 (3) ◽  
pp. 321-324 ◽  
Author(s):  
ALEJANDRO S. MAZZOTTA ◽  
DAVID E. GOMBAS
Keyword(s):  
Listeria Monocytogenes ◽  
Heat Resistance ◽  
Outbreak Strain ◽  
Death Time ◽  
Thermal Death ◽  
Z Value ◽  
D Values ◽  
Hot Dog ◽  
Thermal Death Time ◽  
Phosphate Buffered Saline

The heat resistance of a strain of Listeria monocytogenes responsible for a listeriosis outbreak in hot dogs was not higher than the heat resistance of other L. monocytogenes strains when tested in tryptic soy broth and in laboratory-prepared hot dog batter. For the thermal death time experiments, the cells were grown to stationary phase or were starved in phosphate-buffered saline, pH 7, for 6 h at 30°C. Starvation increased the heat resistance of L. monocytogenes in broth but not in hot dog batter. D-values in hot dog batter were higher than in broth. For the hot dog formulation used in this study, cooking the hot dog batter for 30 s at 71.1°C (160°F), or its equivalent using a z-value of 6°C (11°F), would inactivate 5 logs of L. monocytogenes.

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.

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 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.

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.

scholarly journals STUDIES ON THE THERMAL DEATH TIME OF SPORES OF CLOSTRIDIUM BOTULINUM

1922 ◽  
Vol 79 (15) ◽  
pp. 1239 ◽  
Author(s):  
Ernest C. Dickson ◽  
Georgina S. Burke ◽  
Dorthy Beck ◽  
Jean Johnston ◽  
Harriet King
Keyword(s):  
Clostridium Botulinum ◽  
Death Time ◽  
Thermal Death ◽  
Thermal Death Time
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