This method is an effort to assess risk in aseptic processing. We believe because we have broadened the perspective of risk relative to aseptic processing that if nothing else we have increased awareness that risk can vary substantially in what are perceived by many to be equivalent (and thus equally acceptable) practices and technologies.
Risk Analysis Methods
• Fault Tree Analysis (FTA)
• Failure Mode and Effect Analysis (FMEA)
• FMECA- which adds “criticality” to FMEA
• Hazard Analysis and Critical Control Point (HACCP)
• Hazard and Operational Studies (HAZOP)
However, are any of these methods directly applicable to aseptic processing?
Aseptic Risk- What is it?
• Risk as defined by FMECA = criticality of the occurrence X frequency of occurrence.
• This is a definition that can be readily applied to aseptic processing.
• What is difficult in aseptic processing is actually measuring an “occurrence”
• One could argue that EM provides a measure of “occurrence”, but this is theoretical at best.
• Current EM methods have an uncertain correlation to microbial contamination, and is unavailable in real time.
Risk Assessment by Dr. W. Whyte
No. of microbes deposited on product =
C x S x Pd x Pa x T
C=concentration of microbes in the source (people)
S= quantity of air or material dispersed from a source over time
Pd= proportion of organisms effectively transferred
Pa= proportion of organisms that arrive into the product area
A= area onto which the organisms are deposited
T= time during which microbes could be transferred.
Deposition Models + and –
• This model takes in account technical conditions that have been included in informal risk assessment for years:
• Size of container opening
• Exposure time to the environment
• Estimated microbial content in air
• How does that relate to the numbers of microorganisms detected on surfaces (and deposited in the product perhaps?)
• RODAC® samples
• Settle plates
• The first two of these are relatively easy to determine; the last can only be estimated.