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Clostridium botulinum can grow and form toxin at below 4.6


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#1 Zeeshan

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Posted 03 July 2019 - 11:46 AM

Reference: https://www.ncbi.nlm...ov/pubmed/39257

 

It is generally accepted that in Clostridium botulinum both growth and toxin formation are completely inhibited at pH values below 4.6. This critical pH value has been confirmed by many investigators using food as substrate or culture media. Occasionally growth of C. botulinum and toxin formation at pH values lower than 4.6 have been reported. In these cases the authors ascribed the unexpected outgrowth and toxin formation to local pH differences in inhomogeneous media and growth of C. botulinum before pH equilibrium, or to the fact that fungi created microenvironments within or adjacent to the mycelial mat, where the pH was higher than 4.6 as was demonstrated by Odlaug and Pflug. General assumption that C. botulinum does not grow below pH 4.6 is incorrect. We have observed that growth and toxin formation by C. botulinum can take place in homogeneous protein rich substrates (containing 3% or more soya or milk protein) at pH values lower than 4.6.

Any comment or supporting views??


Edited by Zeeshan, 03 July 2019 - 11:48 AM.


#2 GMO

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Posted 03 July 2019 - 11:50 AM

Any references?
 

Anecdotally the pH 4.6 is supported by the history of safe use, i.e. the very low levels of C. botulinum poisonings.

 



#3 EagleEye

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Posted 03 July 2019 - 12:05 PM

Reference: https://www.ncbi.nlm...ov/pubmed/39257

 

It is generally accepted that in Clostridium botulinum both growth and toxin formation are completely inhibited at pH values below 4.6. This critical pH value has been confirmed by many investigators using food as substrate or culture media. Occasionally growth of C. botulinum and toxin formation at pH values lower than 4.6 have been reported. In these cases the authors ascribed the unexpected outgrowth and toxin formation to local pH differences in inhomogeneous media and growth of C. botulinum before pH equilibrium, or to the fact that fungi created microenvironments within or adjacent to the mycelial mat, where the pH was higher than 4.6 as was demonstrated by Odlaug and Pflug. General assumption that C. botulinum does not grow below pH 4.6 is incorrect. We have observed that growth and toxin formation by C. botulinum can take place in homogeneous protein rich substrates (containing 3% or more soya or milk protein) at pH values lower than 4.6.

Any comment or supporting views??

 

Hello,

 

The highlighted part explains one of such a chance. When consider occurrence of such many dynamics in the real micro-environmental niches, many others could have not yet described. Co-existence of many such factors at different proportions may suit the growth of microbes across the varying space and time.



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#4 Charles.C

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Posted 03 July 2019 - 12:32 PM

Hi Zeeshan,

 

Just to note that the reference is dated 1979.

 

A more recent assessment might be useful for comparison purposes. Possibly with specific context to Foods included.


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Charles.C


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#5 Zeeshan

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Posted 04 July 2019 - 06:36 AM

Hi Zeeshan,

 

Just to note that the reference is dated 1979.

 

A more recent assessment might be useful for comparison purposes. Possibly with specific context to Foods included.

This is one of the reasons why I posted it over here. But IMHO the factors supporting growth of c.bot are still the same in 2019  as they were in 1979?? only what is controllable in 2019 is the advance technology which can prevent it.



#6 Zeeshan

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Posted 04 July 2019 - 06:39 AM

Any references?
 

Anecdotally the pH 4.6 is supported by the history of safe use, i.e. the very low levels of C. botulinum poisonings.
 

I have mentioned the reference. Actually it is a research paper and i could not open it completely as probably it is a paid content.



#7 Scampi

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Posted 08 July 2019 - 07:52 PM

the world is awash with referances

 

https://www.fsis.usd...pdf?MOD=AJPERES

https://jfoodprotect...2-028X-42.3.245

https://www.leatherh...m-botulinum.pdf

 

The differeance now is that we have a MUCH better understanding of the HURDLE technology that is involved in processing food. Getting botulism spores to inactivate CANNOT be done by pH alone, but it is actually the combination of pH, salt, sugar and time/temperature/pressure that inactivates the spores

 

See also https://fbns.ncsu.ed.../Fflbiblio1.htm

 

https://www.research...s_on_Foodstuffs

https://pdfs.semanti...814c6e15d0e.pdf

 

There is so much more research done since 1979 that there is almost no value in looking at that paper


Because we always have is never an appropriate response!





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