The Growth of Clostridium Botulinum in Acid Bread Media

Ingram, M.; Robinson, R. H. M.

doi:10.1111/j.1365-2672.1951.tb01994.x

Cited by 13 publications

(4 citation statements)

References 14 publications

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“…The lowest pH permitting growth and toxin production of C. botulinum is 4.7 to 5.0, based on numerous strains, inoculum levels, and culture media (11,15,21). Judged by the data presented here, there is no evidence to show that type C can grow at any lower pH than the other botulinum types.…”

Section: Discussionmentioning

confidence: 66%

Minimal Growth Temperature, Sodium Chloride Tolerance, pH Sensitivity, and Toxin Production of Marine and Terrestrial Strains of Clostridium botulinum Type C

Segner¹,

Schmidt²,

Boltz³

1971

Applied Microbiology

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Minimal growth temperatures of four marine and two terrestrial strains of Clostridium botulinum type C were determined in a laboratory culture medium, fortified egg meat medium (FEM), and in ground haddock. The inoculum equaled 2 x 106 viable spores per tube with five-tube replicate sets. The spores were preheated in aqueous suspension at 71 C for 15 min prior to inoculation to reduce toxin carry-over. Similar results were obtained in both substrates. Both the marine and the terrestrial strains grew at 15.6 C, but only the terrestrial strains grew at 12.8 C. None of the strains grew at 10 C during prolonged incubation. The sodium chloride tolerance and the pH sensitivity of the marine and the terrestrial strains were determined at 30 C. The basal medium consisted of beef infusion broth. The inoculum level equaled 2 x 106 unheated spores per replicate. Growth was inhibited at salt concentrations from 2.5 to 3.0%. The terrestrial strains were more pH-sensitive than the marine strains. Whereas the terrestrial strains failed to grow below pH 5.62, three of the marine strains grew at pH 5.10, but not at pH 4.96, during extended incubation. One marine strain grew at pH 5.25, but not below. FEM and proteose peptone-Trypticase-yeast extract-glucose medium permitted the production of high levels of botulinum toxin among four media tested. Toxin produced by the marine and terrestrial strains showed no increase in toxicity after incubation with trypsin.

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Section: Discussionmentioning

confidence: 66%

Minimal Growth Temperature, Sodium Chloride Tolerance, pH Sensitivity, and Toxin Production of Marine and Terrestrial Strains of Clostridium botulinum Type C

Segner¹,

Schmidt²,

Boltz³

1971

Applied Microbiology

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“…Nevertheless, it appears unlikely that growth and toxin production will occur below pH 4.8, the lowest pH permitting growth of types A and B (5,10).…”

Section: Discussionmentioning

confidence: 99%

“…It is generally accepted that outgrowth of spores of the proteolytic types A and B C. botulinum is inhibited at pH 4.6 (5,11). However, the lowest pH permitting outgrowth of spores of type E C. botulinum has not been documented as well.…”

mentioning

confidence: 99%

Effect of Sodium Chloride and pH on the Outgrowth of Spores of Type E Clostridium botulinum at Optimal and Suboptimal Temperatures1

Segner¹,

Schmidt²,

Boltz³

1966

Applied Microbiology

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SEGNER, W. P. (Continental Can Co., Inc., Chicago, Ill.), C. F. SCHMIDT, AND J. K. BOLTZ. Effect of sodium chloride and pH on the outgrowth of spores of type E Clostridium botulinum at optimal and suboptimal temperatures. Appl. Microbiol. 14:49-54. 1966.-The sodium chloride inhibition of spore outgrowth of four strains of type E Clostridium bolulinum was determined in a Trypticase-peptoneglucose (TPG) medium. At 16, 21, and 30 C, spores of three strains required 5.0% and one strain 4.5% salt for complete inhibition during 1 year of incubation. At 8 and 10 C, spores of the four strains required 4.5% salt for definite inhibition. Salt concentrations slightly lower than those providing inhibition tended to extend spore outgrowth time at low temperatures. The minimal pH permitting outgrowth of type E spore inocula was affected by the concentration of reducing compound present in the system. When either 0.02% sodium thioglycolate or 0.05% L-cysteine hydrochloride was used, outgrowth at 30 and 8 C occurred at much lower pH levels than when 0.2 % thioglycolate was added. At 30 C, spores of one strain showed outgrowth in TPG medium as low as pH 5.21 with an inoculum of 2 million spores per replicate tube. At a 10-fold higher inoculum, the same strain showed outgrowth at pH 5.03 in one of five replicate tubes. At 8 C, spore outgrowth of the four strains occurred at pH 5.9, but not at pH 5.7, in TPG medium containing L-cysteine hydrochloride.

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“…It has generally been accepted that Clostridium botulinum will not grow and produce toxin in media at pH values below 4.6 (2,3,5,8). A few exceptions have been reported, but in every case these findings have been attributed to localized increases in pH due to growth of other microorganisms (4,9).…”

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confidence: 99%

Toxin Production by Clostridium Botulinum in Media at pH Lower Than 4.6

Tanaka

1982

Journal of Food Protection

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Clostridium botulinum types A and B were able to produce toxin in media containing high concentrations of proteins at pH well below 4.6. A medium containing 15% pork, 0.5% yeast extract, 0.5% glucose and 0.05% cysteine-HC1 at an initial pH between 4.30 and 4.36 produced a toxic sample in as early as one week of incubation at 30 C. Toxin production occurred only when large amounts of precipitated protein were present. The presence of other microorganisms was not required for botulinal toxin production. Media prepared with hydrolyzed protein did not have precipitates and did not support production of botulinal toxin at pH lower than 4.6. Since large amounts of precipitated protein seemed necessary for botulinal toxin production, the possibility of the presence of small, localized pockets of higher pH values within the matrices of precipitated protein could not be ruled out.

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The Growth of Clostridium Botulinum in Acid Bread Media

Cited by 13 publications

References 14 publications

Minimal Growth Temperature, Sodium Chloride Tolerance, pH Sensitivity, and Toxin Production of Marine and Terrestrial Strains of Clostridium botulinum Type C

Minimal Growth Temperature, Sodium Chloride Tolerance, pH Sensitivity, and Toxin Production of Marine and Terrestrial Strains of Clostridium botulinum Type C

Effect of Sodium Chloride and pH on the Outgrowth of Spores of Type E Clostridium botulinum at Optimal and Suboptimal Temperatures1

Toxin Production by Clostridium Botulinum in Media at pH Lower Than 4.6

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