Applying Six Sigma tools to routine water testing

Published: 15-Jan-2015

Six Sigma tools can and have been applied by pharma and biotech manufacturers, who must produce safe, effective, consistent products with increasingly faster cycle times

Lean and Six Sigma are two methodologies used extensively by manufacturers across a variety of industries to remove defects, minimise variability in their processes and reduce waste while increasing customer satisfaction and profits. Six Sigma tools can and have been applied by pharma and biotech manufacturers, who must produce safe, effective, consistent products with increasingly faster cycle times.

Six Sigma makes use of the DMAIC method (Define, Measure, Analyse, Improve and Control) as a framework for improvement. That framework can be applied to many business processes to assess and evaluate improvements. Below is a discussion of the application of the DMAIC framework to the application of automated rapid detection technology to water sampling.


In the case of water testing, the problem could be defined as the time it usually takes to obtain test results – typically three to five days. In that time, batches may continue to be processed downstream with the inherent risk that test results may come back as out of specification. This can be defined as an inefficient process, since results of the water test are unknown for days.

This waiting time could result in losses if finished product cannot be released due to a water contamination event, as well as wasted processing time and personnel hours if product must be rejected. So we could define a more efficient process as one that shortens the incubation/waiting time and provides results faster.


There are several ways to measure the losses from this problem, including:

  • Cycle time
  • Inventory/holding costs
  • Labour and lab costs spent on plating, incubating, counting and manually logging results


Here we delve into the cause and effect relationship: why it takes so many days to obtain bioburden results to release product. The micro-organisms found in water used in pharmaceutical production are highly stressed. Time is needed for these stressed cells to exist in nutrient-rich agar to begin to form colonies that can be viewed by the human eye.


Now that we’ve zeroed in on a cause that can be addressed, we find a solution: a rapid detection technology like the Growth Direct System can detect growing colonies more rapidly than the human eye and shorten the time to results. In addition to rapid detection, high-speed imaging from technologies like the Growth Direct System can provide counts without the need for analysts to manually count plates. In addition, reporting to LIMS can be automated, eliminating the keying of results. This provides both rapid results and reduces potential errors.


Once an improved system is found, we must sustain the changes for lasting results. The Six Sigma method suggests that for the Control phase, the best improvements are irreversible product or process design changes that do not require monitoring to continue to deliver results. Implementation of automated, growth-based rapid detection is a process change that provides a more rapid time to results (allowing for quicker release or rejection) and eliminates variability in counts via imaging technology.

New processes benefit as well

The traditional DMAIC method focuses on solving existing process problems, removing defects and variation when a system is not performing adequately. When used to improve QC workflows, DMAIC can significantly reduce operating and inventory costs.

Automated, growth-based rapid detection can also be a solution when using the DMADV method (Define, Measure, Analyse, Design, Verify; also known as DFSS) to generate a new process where one does not exist. The idea behind DMADV is to begin with the end in mind, to help users create a new process with the efficiencies of Six Sigma built in.

Whether you’re looking to integrate the Six Sigma methodology into an existing process or a new one, the Growth Direct System can help you improve your operational efficiency and consistency, allowing for increased profits or better allocation of resources.

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