Thursday, June 26, 2008

How much is needed to know?

IM is thinking about the various levels of microbiological knowledge, needed to control risk factors of paper and board production.

There is certainly some basic level which shall be reached. Colony counts - both "total count" and counts of more specified microbial groups - serve as the first steps and can very often tell much about current HACCP status to the operators of the machines.

Another basic activity - especially in trouble shooting situations - is microscopy (which has been discussed earlier on this blog). It also gives one view into microbiology of the processes and can also been applied to trouble shooting of product problems whenever challenges of epifluorescence microscopy are available.

Colony counts, of course, tell us about the microbes which are the members of ecosystem / bioreactor called paper machine (also discussed earlier...). Still there are (at least) two points of view which are missing:

  • what kind of environments are favoured by the microbial populations? Temperature, pH, redox potential, certain chemical compounds, any symbiotic relationships, any antagonistic effects, tendency to grow in water / on the surfaces....?
  • what are the main activities of the microbial population? Growth rates? Age of the population (LAG/LOG/KILL)? Special metabolic activities (enzymatic breakdown of starches by amylolytic bacteria etc.)?

It is questionable if any identifications of microbial flora is needed in all cases but, whenever done, ID information tells us, what the microbes are able to do (no matter, they really do not always act like "they should" when referring literature!).

It is the combination of two features - count and activity - of microbial flora which matters. Colony counts alone really do not tell everything about the activities of the flora. Some specified tests - not necessarily very complicated - can be done to understand the main metabolic activities which are going on in the process. One example may be HUGH&LEIFSON tests, teached on all primary microbiology courses of universities, which very easily give information of energy metabolism, favorite carbohydrates, motility and gas formation of isolated bacterial strains.

RAPID METHODS can also tell about the combined effects of count and activity of process flora. PMEU incubator by FINNOFLAG Oy is very much recommended to assays where certain metabolic activities shall be evaluated (see also Enzymatic attack by microbes against different additives can be checked very fast in this way.

A combination of some basic tests for the main representative isolates among total count analyses - basic microscopy, Gram test, oxidase ad catalase tests, HUGH&LEIFSON tests etc. - give valuable information about the main features of total population but this data works as a tool for QC and HACCP only when combined with the experimental results of activity tests and knowledge about sensitivities to different types of biocidic treatments.

Microbial ecology shall still be mentioned as the solid basement for the understanding of potential activities which microbial flora of paper and board machines and their raw material lines is expected to perform. Ecological way of thinking can also tell how the situations may change in near future if one or several basic growth factors are altered.

Future forecasts (like "weather report for a paper machine"- an analogy presented by Helge Keitel, one partner of BIOTOUCH group) should therefore be based on both fast and reliable investigations of process activities and on the overall knowledge of microbial ecology.

As a conclusion, the main task is therefore to answer to the question:

What can happen under certain environmental conditions when certain microbial activities have been detected?

1 comment:

Juha said...

A correction of the BIOTOUCH blog adress: the right form is