Micro Test Parameters + Specs
Hi all,
I’m not a microbiologist and establishing micro test parameters + specs is a new thing for me.......hence, could someone from this area of expertise or experience kindly refer to the table below and let me know how could the test parameters + specifications be made more comprehensive enough to accurately reflect the microbiological safety of finished product (mainly cooked food) such as soups, dressings, sauces, pastries, pastas, risottos, cheeses, confit, meat..?
Also, would be great if someone could highlight the difference and the significance of “Total Coliform Count vs Faecal Coliform Count" .
Food Test
Total Aerobic Plate Count
Not more than 100 000 CFU/g
Total Coliform Count
No guideline
Faecal Coliform Count
< 3.0 MPN/g
Staph. Aureus
Not detected per g
Ice & Water Test
Total Aerobic Plate Count
Not more than 100 000 CFU/g
Total Coliform Count
<1 per 100ml
Total E.Coli Count
<1 per 100ml
Equipment Swab
Total Aerobic Plate Count
Not more than 100 CFU/ml
Total Coliform Count
<1 CFU/ml
Total E.Coli Count
Absent per swab
Hand Swab
Total Aerobic Plate Count
Not more than 100 CFU/ml
Staph. Aureus
Absent per swab
Thank you in advance.
Hi all,
I’m not a microbiologist and establishing micro test parameters + specs is a new thing for me.......hence, could someone from this area of expertise or experience kindly refer to the table below and let me know how could the test parameters + specifications be made more comprehensive enough to accurately reflect the microbiological safety of finished product (mainly cooked food) such as soups, dressings, sauces, pastries, pastas, risottos, cheeses, confit, meat..?
Also, would be great if someone could highlight the difference and the significance of “Total Coliform Count vs Faecal Coliform Count" .
Food Test
Total Aerobic Plate Count
Not more than 100 000 CFU/g Not unusual
Total Coliform Count
No guideline < 100 cfu/g
Faecal Coliform Count Unreliable, best avoided IMO. Use E.coli instead, <10cfu/g
< 3.0 MPN/g
Staph. Aureus
Not detected per g <10cfu/g
Ice & Water Test
Total Aerobic Plate Count
Not more than 100 000 CFU/g High
Total Coliform Count
<1 per 100ml Typical, usually means undetected
Total E.Coli Count
<1 per 100ml Typical, usually means undetected
Equipment Swab Need knowledge of area swabbed/dilution procedure for further interpretation of data
Total Aerobic Plate Count
Not more than 100 CFU/ml
Total Coliform Count
<1 CFU/ml
Total E.Coli Count
Absent per swab
Hand Swab Need knowledge of area swabbed/dilution procedure for further interpretation of data
Total Aerobic Plate Count
Not more than 100 CFU/ml
Staph. Aureus
Absent per swab
Thank you in advance.
Hi Clover,
Some comments above. I have added a few typical levels but note that limits for all the above can vary widely (up and down) with source, product etc Micro.data is notoriously inaccurate/variable.
None of the terms TAPC, TCC, E.coli are directly associated with safety.
S.aureus coag. positive is safety-related.
Faecal Coliform count is sort of obsolete although some people still use it. From memory, was intended to offer a fast method to estimate E.coli. IMO unreliable and not recommended to use, better to use E.coli.
Hi Charles,
I'm so sorry that the table didn't turn out nicely! I'm not sure why but I actually used the "Paste From Word" button to copy paste the table so that viewers are able to view it with ease. Apologize for that glitch and thank you so very much. I'm happy to get some insight on the typical levels.
I agree with Faecal Coliform being obsolete but I need to provide some justification as to why it's unreliable and hence should be replaced with E.coli count. Any journal/book/article more info on this would be good.
Need knowledge of area swabbed/dilution procedure for further interpretation of data
Equipment swab (e.g meat slicer, onion dicer, knifes, table tops preparation area, chopping board, spoon..anything in contact with cooked/raw food)
Hand swab (Swabbing is done on-site, inside kitchen right after workers washed w soap, wipe with tissue and sanitize their hands - no drying..swab only a hand, not a pair of hands, in between fingers, inside and on top of palms)
Sorry, I'm not sure what do you mean by dilution procedure as our samples will then be sent to external third party lab to conduct the test. We basically use a sterile swab tube to do both eq and hand swab. I presume that the lab would then pour & spread the liquid in the swab tube on an agar and incubate. Is it appropriate for me to ask how they interpret their data? Cos the numbers don't mean anything to me unless I know what it represents....
Hi Clover,
Some comments above. I have added a few typical levels but note that limits for all the above can vary widely (up and down) with source, product etc Micro.data is notoriously inaccurate/variable.
None of the terms TAPC, TCC, E.coli are directly associated with safety.
S.aureus coag. positive is safety-related.
Faecal Coliform count is sort of obsolete although some people still use it. From memory, was intended to offer a fast method to estimate E.coli. IMO unreliable and not recommended to use, better to use E.coli.
Hi Clover,
For equipment swab counts, the usual procedure is to swab a defined area Acm2, eg 10cm x 10cm (ie 100cm2)
The swab is usually immersed in X ml of a liquid that comes with the test kit and then sent to ext. lab.
The external lab usually (but not always) take 1ml of X, plate it and report the plate count. But occasionally they dilute a portion first and report the result for this diluted portion, or use a volume other than 1ml. They should internally calculate/report a result (Wcfu) which would be equivalent to the total initial received volume Xml. But labs sometimes only report the result for 1ml of X without noting it. Or other strange numbers.
Assuming you know A and W, the result is then W/A cfu/cm2.
If you don’t know A (and/or sometimes X/W) it’s not possible to compare yr result to general published limits and the result is only useful for internal comparisons.
Can see these 2 threads if you wish to see more practical details -
http://www.ifsqn.com...equipment-swab/
http://www.ifsqn.com...other-surfaces/
Regarding Faecal Coliform, try these refs –
fc1 - The Fallacious Fecal Coliform (IAFP's 12th European Symposium on Food Safety).pdf 222.45KB 46 downloads
fc2 - Comparison of thermotolerant coliforms and Escherichia coli densities in freshwater bodies.pdf 147.69KB 31 downloads
Regarding interpretation of swabbed surfaces -