7 replies to this topic

[MJH]

Hi guys,

I have been looking through the multitude of different micro specs that we have for various products (mainly starches and flours) and I have found a lot of different measurements which I beleive to all essentially be the same:

Total Viable Count
Total Plate Count
Total Aerobic Count
Aerobic Plate Count

does anyone know whether there is a (UK) standard or whether they are all equally acceptable and equivalent?

Cheers,

Matthew

[poppysnoss]

Hi Matthew.

They basically all eman the same. The current ISO standard is:

Attached Files

•  BS EN ISO 4833-2003.JPG   47.69KB   69 downloads

Edited by poppysnoss, 20 September 2010 - 09:32 PM.

[Charles.C]

Dear poppysnoss,

They basically all eman the same.

Rather disagree . Depends on the specific definition used, eg media / temperatures / time. For example I doubt that all countries use 30degC as per yr example ??

(Not to mention the number of times you twist the plate before incubation??)

Must admit flour not my area but IMEX, the above UK temp is rather unusual, 35-37degC more common, Australia is another 30degC exception and there are often good bacteria / scientific reasons for the lower level, unless yr ambient temp is 30deg+

Rgds / Charles.C

[MJH]

Thanks guys,

So my understanding is that while individual methods may vary, they can just as easily vary within a description as they can between descriptions. Thus any of the descriptors are valid for any of the values, but in order to be comparable should state the specific method along-side.

Thanks again for your help!

Matthew

[Tony-C]

Dear poppysnoss,
Rather disagree . Depends on the specific definition used, eg media / temperatures / time. For example I doubt that all countries use 30degC as per yr example ??
(Not to mention the number of times you twist the plate before incubation??)
Must admit flour not my area but IMEX, the above UK temp is rather unusual, 35-37degC more common, Australia is another 30degC exception and there are often good bacteria / scientific reasons for the lower level, unless yr ambient temp is 30deg+
Rgds / Charles.C

It is based on an International Standard so not particularly UK specific.

ISO 4833:2003 specifies a horizontal method for the enumeration of microorganisms, by counting the colonies growing in a solid medium after aerobic incubation at 30 degrees Celsius. Subject to some limitations, it is applicable to products intended for human consumption or the feeding of animals.

Regards,

Tony

[Charles.C]

Dear Tony,

It is based on an International Standard so not particularly UK specific.

As a side-comment, IMO, the ISO micro.standards often significantly over-simplify micro.procedures (for brevity perhaps). Their salmonella / vibrio methodologies (unless they have been updated) are classic examples compared to the US-FDA / BAM for example. Never used their "APC" procedure so cannot comment.

Unfortunately, "plate count" methodologies are famous for their variable results under typical lab. conditions even where standard procedures are supposedly observed. I have had material rejected due simple differences of incubation temperature for a "aerobic plate count". At one time (now?), methods for APC even specified the brand name of media allowed to be used. Variability still occurs in (cheaper?) products although labs are supposed to productively validate their media (??)

My point was primarily to be very "caveat emptor" where micro. data comparisons are to be made. Many labs are prone to using methods "based" on XXX International Standard. The "based" is very user-friendly.

Rgds / Charles.C

[Tony-C]

Dear Tony,
The "based" is very user-friendly.

Rgds / Charles.C

Agreed

I may have mentioned this before but I had a problem with a major International company who rejected several loads of Skimmed Milk Powder (20 Tonnes a time) for high TVC. We found no problem with our TVC results. It turned out that they had "miscalculated" the dilution factor! No apology or anything either.

Regards,

Tony

[DAVE84]

They all are the same....
It depends on person using any specific.....

There is no difference in even methodology..... They are just one thing...... Its done on TSA agar.....

Dave