Gram Staining
Hello Every One,
We are preparing and blast chilling products like curries and gravies. Before releasing those products we are running TPC, Y&M and Coliform test. However, the test lead time consuming around 3- 5 days. We are trying to explore an option of Gram Staining to get qualitative information of product safety like Gram staining ( Positive and Negative) present/ absent to release the batches to market Based on the final results, We will further advise our logistic team send those products to final consumer or B2B supplier. Is it reasonable to take a call based on the Gram staining method which is specified in BAM Method. Secondly, Would like to understand is it reliable to take calculative call based on the gram staining results. Please help me in getting your technical insight.
Regards,
Baskaran.G.
Personally I would not think the gram stain would offer very useful information for your product. Assuming your product is not commercially sterile, you'd certainly expect to see a variety of bacteria in the samples. While the gram reaction (+/-) of a bacteria can give you some decent insight into some of its characteristics (heat resistance, etc), it's not going to tell you whether the bacteria is pathogenic or not. Seems to me like you would not be able to vet any batches based on gram stain results, because the risk posed by a bacteria can't be identified by gram stain alone. I would expect that you'd end up doing lengthy follow-up testing on nearly every sample to confirm if what you're gram staining is a pathogenic risk or not.
For non-sterile products I would think the best way to understand microbial risk is through identifying the microbial load, and testing for key pathogens of concern. Neither of these aspects are very well understood from a simple gram stain.
If you're looking for higher turn-around times, I would look into rapid testing methods. These can be more expensive, but even 3M petrifilms off the top of my head can give you APC, Coliform/E.Coli, YM, and Salmonella in just 2 days.
Hello Every One,
We are preparing and blast chilling products like curries and gravies. Before releasing those products we are running TPC, Y&M and Coliform test. However, the test lead time consuming around 3- 5 days. We are trying to explore an option of Gram Staining to get qualitative information of product safety like Gram staining ( Positive and Negative) present/ absent to release the batches to market Based on the final results, We will further advise our logistic team send those products to final consumer or B2B supplier. Is it reasonable to take a call based on the Gram staining method which is specified in BAM Method. Secondly, Would like to understand is it reliable to take calculative call based on the gram staining results. Please help me in getting your technical insight.
Regards,
Baskaran.G.
As per Post2, this option is probably unworkable/unacceptable.
I think you can now get tests for TPC/Coliform within 24 hours (see earlier threads here) but maybe not Y&M (unsure).
As per Post2, this option is probably unworkable/unacceptable.
I think you can now get tests for TPC/Coliform within 24 hours (see earlier threads here) but maybe not Y&M (unsure).
Thanks Charles. I did not find any relevant threads on TPC - 24 hours turn around. Would be grateful if you can share thread here.
As per Post2, this option is probably unworkable/unacceptable.
I think you can now get tests for TPC/Coliform within 24 hours (see earlier threads here) but maybe not Y&M (unsure).
Personally I would not think the gram stain would offer very useful information for your product. Assuming your product is not commercially sterile, you'd certainly expect to see a variety of bacteria in the samples. While the gram reaction (+/-) of a bacteria can give you some decent insight into some of its characteristics (heat resistance, etc), it's not going to tell you whether the bacteria is pathogenic or not. Seems to me like you would not be able to vet any batches based on gram stain results, because the risk posed by a bacteria can't be identified by gram stain alone. I would expect that you'd end up doing lengthy follow-up testing on nearly every sample to confirm if what you're gram staining is a pathogenic risk or not.
For non-sterile products I would think the best way to understand microbial risk is through identifying the microbial load, and testing for key pathogens of concern. Neither of these aspects are very well understood from a simple gram stain.
If you're looking for higher turn-around times, I would look into rapid testing methods. These can be more expensive, but even 3M petrifilms off the top of my head can give you APC, Coliform/E.Coli, YM, and Salmonella in just 2 days.
ATP will help us to identify indicative micro load if gram staining does not make any relevance for qualitative information. Please advise your technical inputs
As others already said, gram staining wont help you.
if you need a quicker methods
Petrifilm (depending on matrix)
apc in 24 hours
coliform / ecoli in 18-24
yeast and mold 48-72
Good morning Baskaran as previously stated in other posts 3M does have Rapid tests RAC, RCC, RE, and RYM but your inhouse lab must be capable of performing the testing according to the relevant AOAC Official Method of Analysis or AOAC Performance Tested Method for each. There is also the requirement for performance testing of the lab personnel to ensure that they have the knowledge and skills to perform to the documented standard. Just a note that of the tests listed above only the Rapid Yeast and Mold lacks an official AOAC Official Method of Analysis but does have an AOAC Performance Tested Method. (I just went through our first GAP Analysis for our inhouse lab and discovered these GAPs before our audit).
Thanks Charles. I did not find any relevant threads on TPC - 24 hours turn around. Would be grateful if you can share thread here.
as post 7 -
https://www.3m.com/3.../p/d/b00013949/
No doubt other brands exist.
ATP will help us to identify indicative micro load if gram staining does not make any relevance for qualitative information. Please advise your technical inputs
Unfortunately I would not recommend relying on ATP as an indicator of microbial load in a food sample either...in a food sample you will be measuring the ATP from the food as well! ATP is typically used to judge surface sanitation, where residual food particles are also a concern.
For judging microbial load, plate counts are your best option. As others have mentioned rapid tests exist that can get you results in 24-48 hours.
Much appreciated everyone for technical inputs.