Jump to content

  • Quick Navigation
Photo

Positive Control Check for Pathogen Tests

Share this

  • You cannot start a new topic
  • Please log in to reply
4 replies to this topic

BALA Prasanna

    Grade - AIFSQN

  • IFSQN Associate
  • 32 posts
  • 2 thanks
0
Neutral

  • India
    India

Posted 08 November 2019 - 07:13 AM

Dear Team,

                     We dre doing Qualitative test for Salmonella & E.coli as per BAM Method.

 

We are not compare the result with Positive & Negative Control.

 

Is there mandatory to compare the result with Positive & Negative Control.

 

 

Experts pls clarify

 

 

 


Regards,

Bala Prasanna

 

 

Enable GingerCannot connect to Ginger Check your internet connection
or reload the browserDisable in this text fieldRephraseRephrase current sentenceEdit in Ginger×


The Food Scientist

    Grade - FIFSQN

  • IFSQN Fellow
  • 1,057 posts
  • 268 thanks
208
Excellent

  • United States
    United States
  • Gender:Female
  • Interests:Food Science, Nature, SQF, Learning, Trying out new foods, Sarcasm.

Posted 08 November 2019 - 02:06 PM

You still need to check if your results are valid. So you don't get any false negative or false positive...


Everything in food is science. The only subjective part is when you eat it. - Alton Brown.


Thanked by 1 Member:

Hank Major

    Grade - SIFSQN

  • IFSQN Senior
  • 317 posts
  • 101 thanks
33
Excellent

  • United States
    United States

Posted 08 November 2019 - 08:24 PM

A positive control means you run the test on a sample that you know has Salmonella (or E. coli or whatever). It is checking to make sure that the test can detect them.



BALA Prasanna

    Grade - AIFSQN

  • IFSQN Associate
  • 32 posts
  • 2 thanks
0
Neutral

  • India
    India

Posted 09 November 2019 - 04:10 AM

ou still need to check if your results are valid. So you don't get any false negative or false positive...

Everything in food is science. The only subjective part is when you eat it. - Alton Brown.

 

 

Dear Madam,

                     We have checked external lab more then 200 results (including PCR). but we didn't get any positive results.

 

If false negative came it was vary in the external lab results.

 

 Is the Positive control is mantatory to test with sample?

 

Because we can justify with ILC results. 


Edited by BALA Prasanna, 09 November 2019 - 04:16 AM.

Regards,

Bala Prasanna

 

 

Enable GingerCannot connect to Ginger Check your internet connection
or reload the browserDisable in this text fieldRephraseRephrase current sentenceEdit in Ginger×


Charles.C

    Grade - FIFSQN

  • IFSQN Moderator
  • 20,542 posts
  • 5662 thanks
1,544
Excellent

  • Earth
    Earth
  • Gender:Male
  • Interests:SF
    TV
    Movies

Posted 09 November 2019 - 10:11 AM

 

ou still need to check if your results are valid. So you don't get any false negative or false positive...

Everything in food is science. The only subjective part is when you eat it. - Alton Brown.

 

 

Dear Madam,

                     We have checked external lab more then 200 results (including PCR). but we didn't get any positive results.

 

If false negative came it was vary in the external lab results.

 

 Is the Positive control is mantatory to test with sample?

 

Because we can justify with ILC results. 

 

 

Hi Bala Prasanna,

 

^^^^^^

 

also see -

 

https://www.ifsqn.co...is/#entry144567

https://www.ifsqn.co...is/#entry151032

 

 

All this probably comes into the general arena of "Micro. Procedure  Validation".

 

These documents may assist -

 

Attached File  mic1 - Procedure media preparation and growth promotion test.pdf   140.25KB   11 downloads

Attached File  mic2 - Procedure for Validation of Shelf Life of Prepared Micro.Media.pdf   254.11KB   14 downloads

Attached File  mic3 - Procedure for Micro. Media preparation.pdf   115.18KB   7 downloads

Attached File  mic4 - aoac_validation_guidelines_for_food_microbiology.pdf   660.05KB   12 downloads

Attached File  mic5 - micro. method validation US EPA.pdf   1.08MB   11 downloads

Attached File  mic6 - FDA Guidelines Validation methods detection pathogens in foods-Feeds,2015.pdf   1.19MB   15 downloads

Attached File  mic7 - Media growth validation, test methods.pdf   1.84MB   12 downloads

 

Ideally, the lab should probably be doing all these various validation exercises.

In practice it likely depends on what yr iso certification etc demands and what you are actually talking about, eg the latter's safety significance/results etc.

 

For example, IMEX, an unbroken, extended,  history of negative results for something like Salmonella in a raw food is likely a cause for alarm. :smile:


Edited by Charles.C, 09 November 2019 - 10:47 AM.
added

Kind Regards,

 

Charles.C




Share this


0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users