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Scientific Information for ph of fermented vegetables

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#1 jportz

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Posted 08 May 2014 - 05:06 PM

I was wondering if anyone could help me.  Our CCP for fermented vegetables is <4.0 and the industry standard is <4.6 in order to prevent botulism.  I have scientific evidence that states Low pH (3 to 4) and organic acids in acidified  and fermented vegetable products prevents the growth of bacterial pathogens and result in pathogen death. These products have an excellent history of consumer safety, but definitive data is lacking to show that E coli O157:H7 and Salmonella will die off over the rang of conditions under which commercial fermentation occurs. Research has  show n E coli 0157 is the most acid resistant pathogen of concern in acidified vegetables containing acetic acid (pH 3.3 or below) the holding times needed to assure destruction of this pathogen are 6d at 10 degrees C and 2 d at 25 degrees. 

 

If our CCP is <4.0 is this evidence good enough to prove why we have that.  I'm new to this and would appreciate any help.

 

 



#2 Charles.C

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Posted 08 May 2014 - 06:38 PM

Dear jportz,

 

Are you referring to a canned product intended to be shelf stable at ambient temperature or ?

 

Rgds / Charles.C


Kind Regards,

 

Charles.C


#3 jportz

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Posted 08 May 2014 - 07:41 PM

I'm refering to fermented product acidified foods that are intended for further processing and some are RTE (Ready To Eat) foods. Some shelf life for Puree, and olives are shelf life of 6 months refrigerated and other like celery, carrots, peppers, relish are 6 months ambient and 9 months refrigeration.



#4 Charles.C

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Posted 09 May 2014 - 09:41 AM

Dear jportz,

 

The product safety with respect to E.coli 0157 for type of products you mention  appears to have become a matter of debate particularly following the incidents with fruit juices. Although I believe so far no actual incidents with fermented vegetables ?

 

The answer to yr query may depend on yr required scope and the actual evidence.

 

Current FS knowledge seemed to be illustrated by items like –

 

Attached File  acidified foods (2013) - FS considerations.pdf   208.45KB   34 downloads

 

http://www.ncbi.nlm....pubmed/21535844

 

http://www.fda.gov/f...f/ucm222618.htm

 

Yr shelf life/storage method(s) comment indicates that different processes/results are in use.

 

I noticed this comment in one of above refs –

 

a 5-log reduction was achieved within 1 to 16 d depending on pH, acid concentration, and temperature.

 

 

Is the T/t data you mention  valid for one particular product/mixture or ? A generic statement will require the evaluation of overall situation requirements for food safety, eg pH <=4 in combination with ? (or vice-versa).

 

Not sure if that helps to answer yr query or not ? :smile:

 

Rgds / Charles.C

 

PS - added - 

 

After some more searching, the nearest example i could find to a generic statement was this -

 

in a representative acidified vegetable product (cucumbers) with a pH at or below 3.3, a 5-log reduction in viable cell counts for acid-resistant pathogens occurred without a heat treatment within 6 days. We have shown that manufacturers of acidified foods with pH values at or below 3.3, with acetic acid as the primary acidulent, can therefore safely produce these products without heat treatment.

 

(Breidt,2007)

I guess above was the basis of yr OP. The above comment related to temperatures above 10degC. Prediction of specific T-t values will require use of D,z values.

 

If our CCP is <4.0 is this evidence good enough to prove why we have that

if you are asking whether a pH of, say, 3.9. will allow a 5log reduction at 10degC within 6 days, the answer requires further knowledge of the effect of pH, yr actual product, maybe other system data. If you are referring to cucumber, same conditions as above quoted research and time is proportional to pH, the answer is probably no.

 

Additionally, a practical situation of fermented vegetables will presumably differ to the mixture in above research ?  i noticed this comment -

 

Given the most permissive conditions tested for the survival of E. coli O157:H7 (pH 4.5 for commercial brine samples at 23degC or pH 3.9 with brine fermented by L.mesenteroides at 10degC), a 5-log reduction was achieved within 23 d. Brine pH values below 3.3 required less than 4 d to achieve a 5-log reduction regardless of temperature (10degC or higher) with commercial brines or in active competition with LAB.(cf  6days In previous discussed acid mixture).

 


Kind Regards,

 

Charles.C


#5 Charles.C

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Posted 12 May 2014 - 08:02 PM

Dear jportz,

 

Any further comments ?

 

Rgds / Charles.C


Kind Regards,

 

Charles.C


#6 jportz

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Posted 13 May 2014 - 01:43 AM

I was told that the products we produce aren't as high risk for ecoli so, our pH at <4 would be ok.  But, I have to be able to explain it to the auditor and I'm new at all of this. 



#7 Avila

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Posted 13 May 2014 - 05:05 AM

Dear jportz,

You need to provide some literature from microbiology research institute regarding limiting condition for those bacterias growth as a scientific reference. Below is an example,

http://www.fda.gov/d...n/UCM252447.pdf

Good luck

Rgds,

Avila


Edited by avila muncar, 13 May 2014 - 07:34 AM.






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