August 22nd, 2017

Let’s pick up with: “If no method provides a perfect measurement of microbial contamination, which one should I use?”
Currently, the primary microbiological test that I use for testing fuels, fuel-associated water and fuel system components is ASTM D7687 Test Method for Measurement of Cellular Adenosine Triphosphate in Fuel and Fuel-associated Water With Sample Concentration by Filtration. The ASTM method is based on a test kit manufactured by LuminUltra Technologies, Ltd.; with whom I…


July 25th, 2017

In Part 13, I discussed culture testing. One of the points I made was that any given culture test (of which there are >5,000) is unlikely to detect >1 % of all of the microbes present. Before moving on to discuss methods that detect more of the microbes present – in terms of percent detection of each type of microbe and the fraction of the different microbes present that are detectable – I will invoke one of Donald Rumsfeld’s most famous quotes:
“There are known knowns. These are…


July 6th, 2017

Since November, this series has progressed through fuel system sampling, sample handling and non-microbiological tests used to detect biodeterioration. This post, and the three to follow, will cover microbiological testing.

Let’s take another look at the figure (fig 1) that accompanied Part 3 (December 2016):

Fig 1. Ability of different microbiological test method to detect all microbes present in a microbiome.

The largest circle represents the total microbiome – all the microbes…


May 12th, 2017

I recently received a question regarding the use of one tank-stick to measure multiple tanks. The question was: “if you stick a tank that is contaminated into the next tank, will it contaminate the second tank?”  That is: can the microbial load carried over from UST to another, on a gauging stick, infect the second UST?

Given how much press there has been lately about how easy it is to spread disease through brief, hand contact with contaminated surfaces, this is an excellent…


April 24th, 2017

We are progressing from test methods that do not require any equipment (other the tools you need for sample collection) to those that require increasingly expensive tools. You can complete basic gross observations by relying on your eyes and nose. The physical tests I suggested in Part 10 require simple tools; including a magnetic stirring bar retriever, disposable syringes, filter pads and in-line filter holders. In this blog, I’ll discuss a couple of simple chemical tests. However, with one…



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