Ask the Expert: Looking to Increase Efficiency of Your Pathogen Detection Process?

By Food Safety Tech Staff
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Pathogen enrichment is a critical part of any microbiological testing workflow.

Pathogen detection – made challenging with the increase in numbers of composite samples that require even larger volumes of media per sample – are time-consuming and involve bulky media handling by laboratory personnel. Not only do these factors make life in the lab more difficult, but also, they increase the risk of introducing contamination. 

The following questions provide insight into more efficient ways to prepare media.

Q: What are some ways to manage the increased media production requirements, and what are some of the bottlenecks in the media kitchen when dealing with composite samples for pathogen testing?

A: Composite samples are larger than traditional food samples and therefore require the addition of more culture media before incubation. Larger volumes of media preparation (i.e. sorting, autoclaving) is one of the largest sources of bottleneck for composite samples for pathogen testing. It’s not unusual for several hundred composite samples to be tested daily on a regular basis – this situation is only magnified when managing composite samples that require up to 15 times more than a traditional sample.

The issue with large volumes of media is that media containers and samples are fairly heavy and cumbersome to move, with equally demanding turnaround time. For these reasons, the entire process must be industrialized to maintain lab productivity.

Choosing a media that is composed of premium raw materials ensures high recovery and growth rates of bacteria, which are essential for the subsequent use of rapid testing methods. Additionally, selecting a media that meets industry performance standards as described in ISO 11133, helps reduce required quality control measures.

Q:  How can I increase my media production without having to scale up my media kitchen to handle the workload?

A:  Merck Millipore’s Readybag® media pouches with granulated culture media enable pathogen testing of composite food without making major changes. Readybag media pouches do not require capital equipment investment and involve less labor than both high efficiency and traditional methods for sterile media production. Use of pre-weighed, gamma-irradiated Readybag pouches eliminate all preparation steps and reduce typical sample preparation and autoclaving time by more than 50 percent. Performance tests confirm that Readybag media provides equivalent results compared to non-irradiated, autoclaved culture media.

A study performed by Cherney Microbiological Services (Green Bay, WI, USA) demonstrated the time, utility and space savings using Readybag granulated enrichment media for composite food samples as compared to both high efficiency and traditional preparation methods using autoclaving. The study examined the labor required, media cost, utility and associated electricity costs for each of the three methods (traditional autoclave, high efficiency and Readybag method).  Observations and measurements were made using laboratory personnel within the normal workflow of Cherney’s laboratory.

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