To swab or not to swab, that is the question: environmental swabs vs. sponges

A frequent question we at Neogen hear from sanitation testing customers is, “When should I use a swab vs. a sponge for collecting my environmental samples?” Today, we’ll take a look at the difference between the two sample collection tools.

Typically, routine environmental monitoring in the food industry is done with sample collection sponges — sometimes colloquially referred to as “spongesicles,” for their resemblance to popsicles. The sample sponge is systematically wiped on a surface over a wide grid pattern to take in as wide a sample range as possible. A larger sample size is collected, and this sample is then enriched.  The goal here is to get an idea of what types of bacteria, yeast or mold are present in a general area of the plant. This knowledge can be used to evaluate whether a facility’s routine sanitation procedures, performed as part of the Master Sanitation Schedule, are effective or not.

The sponge method of testing is like a commercial fishing operation casting a wide net in an area, and seeing what’s in the net once it’s recovered.

With vectoring to find a contamination source, which we covered recently here on our blog, a facility might consider using a swab or small foam tool — instead of a sponge — as more precision is desired when trying to seek out the source of an environmental contamination.

To continue with the fishing analogy: As a lone fisherman in a boat on a lake looking to hook a bass, you want to remain very close to where your line is cast, so if you get a bite, you can return to the area easily. If you use a wide net, it would be much harder to quickly pinpoint where that bite — or hit — came from, and where exactly the fish – or bacteria – are in the water.

A swab can also be useful when the space being sampled is a tight fit, such as a freshly cleaned new piece of equipment entering the processing environment, and other areas that a sponge may have difficulty reaching such as nozzles, drains and valves.

If you manage sanitation in a facility, keep this comparison in mind as you hone in on the target of a vectoring effort, or when conducting routine environmental monitoring. With routine monitoring, it’s best to cast a wide net to get a wide sample size. When investigating the source of an environmental concern, or clearing equipment (both new and existing) after a construction project, a fine and precise sample size that targets food contact surfaces and surrounding areas allows problem areas to be located faster.

Usually when tracking the source of contamination, or declaring an area free of contamination, there is a need for faster results than traditionally available. One of Neogen’s newest tests, ANSR® Listeria Right Now™, can deliver results for six strains of Listeria in under an hour without the need for sample enrichment. The test is analogous to an adenosine triphosphate (ATP) test for Listeria, allowing users to take immediate action re-cleaning equipment before running.

For information about Neogen’s food safety solutions, check out our website.

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