Clostridium botulinum

Gram ± Clostridium botulinum

Positive

Shape Clostridium botulinum

Rod

Sporeformer? Clostridium botulinum

Yes

Intoxication/infection Clostridium botulinum

Intoxication

Optimal temperature? Clostridium botulinum

5-45?

optimal pH Clostridium botulinum

5-8

(An)aerobe? Clostridium botulinum

Anaerobe

Does it survive in dry conditions? Clostridium botulinum

Yes

Source Clostridium botulinum

Soil, vegetables

Survival Clostridium botulinum

Its spores are highly resistant structures

Two groups of Clostridium botulinum

• Group 1: Proteolytic strains

  • Growth > 10 C

  • Heat resistant spores

  • Botulinum cook (12D) for low-acid foods stored at ambient temperature (3 min at 121 C)

• Group 2: Non-proteolytic strains

  • Growth > 3C

  • Spores inactivated at 90 C

Disease Clostridium botulinum

• Clostridium botulinum creates a toxin, with is lethal

• This toxin is activated in the gut of humans

• Symptoms: nausea, vomiting, muscular pain, double vision

• Infant botulism: The digestive system ingests bacterial spores, instead of only the toxin, which grows and produces toxin within the gut. 

Incubation & duration of botulism with Clostridium botulinum

• Incubation: 12-48 h

• Duration: 1-8 days

Prevention and control Clostridium botulinum

• A "Botulinum cook" is a specific heat treatment required for low-acid canned foods (pH > 4.5) to ensure a 12-log (12D) reduction in the level of Clostridium botulinum. 

• At pH<4.5 Clostridium botulinum does not grow anymore below this pH

• To achieve this 12D reduction (with D121 = 0.2 min), 2.4 minutes of heating at 121°C is needed, often referenced as an F0 or F121 value of 3 minutes. 

• It is important to note that a "Botulinum cook" does not achieve full sterilization, meaning other spoilage organisms may still survive 

• Nitrite above 100 mg/kg inhibits Clostridium botulinum, which might survive the heating process applied to many cured meats.   

Type A, B, C, D, E and F Clostridium botulinum

• Type A, B, E and F cause human botulism where toxin blocks end of nerves

• Type C and D are found on decaying carcasses

• and type A is also used for muscle paralysis. (Botox)