5 Limitations of Traditional Microbial Testing

While most pharmaceutical manufacturers have embraced new, automated methods in their production processes, many have been slow to adopt cutting-edge techniques and equipment for microbial quality control. When it comes to microbiological testing, the century-old manual method is still the norm, and most companies are spending countless hours of highly skilled labor on repetitive tasks.

Fortunately, rapid microbiological methods (RMM) are quickly becoming more popular among manufacturers and regulators alike. Regulations have changed to make the migration to RMM easier than in the past.  these changes, plus the added benefits of labor savings, reduced OOS investigations make it advantageous to move away from the traditional method.  Here are five of common and impactful limitations of the manual method.

Time Required

The traditional method requires time for microbes to grow and multiply enough to be seen by the human eye.  Once the colonies are visible, ever plate needs to be counted and recorded.  Highly valuable trained microbiologist time is wasted analyzing hundreds of plates -- many of which may have no contamination.  Using the Growth Direct^TM System reduces the total test time by about 50%. Because the system reads the plates every four hours, it can detect contamination starting in hours.  In addition, the system automatically handles the hundreds of plates reading, recording and reporting results automatically, saving valuable microbiologist time. 

Limited Accuracy

Testing accuracy is key in the high-risk, highly regulated pharmaceutical industry, and manual colony counting allows for a great degree of human error. Colonies must grow to millions of cells before they can be detected by the naked eye, and even the most well-trained and experienced technicians can miscount. When dealing with strict specifications for acceptable levels of growth, this level of inaccuracy can easily lead to both unnecessary OOS investigations and undetected contamination.

Transfer Errors

Some tests require serial incubation, where samples are transferred from one incubator to another at a different temperature at a specific time. RMM technologies such as The Growth Direct^TM System automate this process. The manual method requires additional human intervention, while every time a technician transfers a sample, there is potential for an error, which may result in an out-of-specification event.

Data Entry Errors

Even when technicians perform their manual counts perfectly, there is an opportunity for error when they record the counts on paper or in their LIMS. Whether they've exhibited growth or not, each sample must be accounted for, and technicians can make mistakes when dealing with hundreds of samples. Ultimately, these errors lead to the same problems as inaccurate counting – unnecessary investigations and unnoticed contamination.

Difficult Interim Counts

Manufacturing departments often request interim counts, especially when products are undergoing time-consuming sterility tests or when large volumes are awaiting shipment. While automated technologies allow personnel to instantly check their most recent counts, the manual method requires just as much labor for interim counts as it does for final results. Technicians must pull plates from incubators, perform manual counts and record results, and each task presents additional opportunity for in-process contamination and human error.

When you invest in an RMM system like Growth Direct™, the return on investment is easy to see. To learn more, download our free guide “Quantifying the Economic Benefits of the Growth Direct™ System.”