Fouling Cell Technology
In food, beverage and pharmaceuticals manufacturing, microbiology results are key. However, by the
time you detect a colony forming unit (CFU), you know your process is contaminated and your
actions are reactive.
With the proper set of tools process cleaning can be a science rather than an art. The proper tools measure
the chemistry and biology occurring on your pipe and tank walls. You can be proactive
rather than reactive.
The first hurdle is the pipe or tank wall itself. It’s difficult to analyze a curved pipe surface,
particularly in a line that may run hundreds of feet and can’t be removed from production. Fouling cell
technology overcomes this problem. Fouling cells are removable, polished stainless steel coupons or
discs that can be installed in any location in a manufacturing process. Chemical or biological fouling
that occurs on a pipe or tank wall will also happen on the fouling cell surface.
The fouling cell surface is an ideal sample for surface-specific analytical measurements. Reflection
Fourier Transform Infrared spectroscopy (FTIR) can easily measure the conditioning layer of fouling,
down to less than 100 A in film thickness. FTIR can also pick up subtle changes in fouling film
chemistry over time.
Reflection FTIR on the fouling cell surface can directly measure the impact of your Clean-In-Place
(CIP) process. FTIR and fouling cells can tell you what fouling your CIP is or isn’t
removing.
An equally valuable tool is epifluorescence optical microscopy. With the appropriate nucleic
acid stains, fluorescence microscopy can help determine whether the fouling on a disc is
biofilm or not, and how well your CIP process is working to control biofilm.
There are many other surface analytical techniques that work with fouling cell technology:
x-ray fluorescence (elemental analysis), scanning electron microscopy (fouling film morphology),
x-ray photoelectron spectroscopy (surface chemical analysis), ellipsometry (film thickness),
atomic force microscopy (AFM), etc.
The polished stainless steel fouling cell disc opens up a window of knowledge on what is really happening
on your pipe walls, and allows you to get an early indication of process health, before you see a colony
forming unit.
Wall fouling inside a chemical process transfer line:
Fouling cell discs (mirror-polished end caps) can be installed in a process to collect
wall fouling:
Specular reflection:
Once fouling has accumulated on a disc, specular reflection Fourier Transform Infrared Spectroscopy
(FTIR) can determine the chemistry of the fouling layer and the rate of deposition. FTIR can also
directly measure cleaning effectiveness of a CIP process.
FTIR spectra from 2-day and 4-day biofilm on fouling cell disc:
FTIR and fouling cells can follow the growth of a biofilm over time.
