ON-Site Testing – Understanding and deciding
USING ON-SITE MICROBIAL TESTING TO GO BEYOND REGULATORY COMPLIANCE
Regulatory compliance for prevention of infection by pathogens and overall contamination control is of course an important aspect of your business, and one of the reasons to run microbiological tests. However, it shouldn't be the only or even the main reason for testing.
Regular microbial testing, and recording the results, will allow you to build up a comprehensive picture of the microorganisms present in your environment and whether they are under control. You can of course perform statistical analysis to obtain complex and comprehensive data on trends and performance. However, the advantage of regular microbial testing is that a contamination event or a loss of control results in a very large and noticeable swing in results, visible with the naked eye!
Maintaining regular monitoring or even an environmental monitoring program gives you a number of advantages :
- If an auditor (customer, headquarters, inspector, …) sees data that supports practices, he may have suggestions regarding those practices, but will be sensitive to the fact there is data available and that it was put to good use
- If you ever want to set up sophisticated analysis in the future, you will have historical data
- If you want to conduct your own investigation into an event, any historical data you have available will most likely save you time and resources
A CRASH-COURSE IN MICROBIOLOGY – DEFINING A QUESTION
You should define a question that your on-site testing and data collecting will attempt to answer, along with concrete actions to act on results.
Here are some examples :
A. Question : How « clean » is this tool after cleaning?
Potential actions: Intensify frequency / reinforce sanitation... or not
When to sample: after cleaning
B. Question : How much contamination builds-up during normal operations?
Potential actions: increase sanitation frequency, modify design or practices... or not
When to sample: prior to cleaning
C. Question : How efficient is the cleaning operation?
Potential actions: modify the cleaning protocol or change sanitant... or not
When to sample: prior and after cleaning
TEST RESULTS AND OBTAINING DATA
WHAT CAN WE DO ABOUT THIS?
Collect larger samples:
With nomad Testers, the sample volume is fixed at 1 ml. testing more than that is not possible.
With nomad surface swabbing kits, larger surface areas can be tested.
Drawing several samples and pooling them together before testing will compensate to some extend for body heterogeneity
Repeat tests (replicate testing)
Run 3-5 tests on the same body and report results as the average of the 3-5 results. This practice compensates for natural distribution in results and for product heterogeneity.
You can also calculate the standard deviation which is valuable information for differentiating a normal result from a potentially problematic one
However, doing extra tests also significantly increases the cost of obtaining a result. We do still recommend this approach during the initial phase of testing, to determine baseline standard deviation and check protocol reproducibility
Finally, be sure to interpret count results knowing that two individual results that are half/double one of the other are potentially "the same" i.e. you can consider that a count of 50 is not necessarily a different result from a count of 100. "Helpfully", microbial growth typically translates in significant changes in counts!
Find out more about how you can implement nomad in your industry!
ALERTING YOU TO PROBLEMS
Ideally you should be working based upon a year of historical data as microorganism growth is affected by temperature and humidity. These factors also affect the plant entrants (raw materials, air, staff) as well as the environmental contamination within the plant.Around 100 data points collected over at least a year allows solid statistical analysis.