Category: Laboratory & QA/QC

An essential part of any robust environmental sampling program is ensuring concise, representative samples. Without ensuring the quality of a sample, one can certainly not ensure the quality of a sampling program, or the quality of one’s product.

One of the most popular methods of surface sampling used by our customers in the food industry are sponge samplers for larger areas (swabs being used most often for smaller and harder-to-reach areas). Often composed of cellulose or polyurethane, sponge samplers are everyday essentials for our food industry customers, that help proactively mitigate against environmental contamination concerns. Though a common, daily practice in a food processing facility, it is useful to occasionally revisit sampling techniques to ensure the best representative samples are being taken by employees.

So, if you haven’t revisited your sampling best practices lately, here is what the CDC recommends for proper sampling with a cellulose sponge. Though, specifically cited in a piece regarding Bacillus anthracis, the following is a great model to consult with for sampling methodology, overall.

Cellulose Sponge Sampling Procedure:

1. Wearing a clean pair of gloves over existing gloves, place the disposable template over the area to be sampled and secure it. If a template cannot be used, measure the sampling area with a disposable ruler, and delineate the area to be sampled with masking tape. The surface area sampled should be less than or equal to 100 in²
   (645 cm²).
2.  Remove the sterile sponge from its package. Grasp the sponge near the top of the     handle. Do not handle below the thumb stop.
3.  If the sterile sponge is not pre-moistened, moisten the sponge by pouring the 10 mL container of neutralizing buffer solution over the dry sponge.
4. Wipe the surface to be sampled using the moistened sterile sponge by laying the widest part of the sponge on the surface, leaving the leading edge slightly lifted. Apply gentle but firm pressure and use an overlapping ‘S’ pattern to cover the entire with horizontal strokes.
   
5. Turn the sponge over and wipe the same area using vertical ‘S’ strokes.
6. Use the edges of the sponge (narrow sides) to wipe the same area using diagonal ‘S’ strokes.
   
7. Use the tip of the sponge to wipe the perimeter of the sampling area.
8. Place the head of the sponge directly into a sterile specimen container. Break off the head of the sponge by bending the handle. The end of the sponge handle, touched by the collector, should not touch the inside of the specimen container. Securely seal and label the container (e.g., unique sample identifier, sample location, initials of collector, and date and time sample was collected).
9. Place the sample container in a re-sealable 1-quart plastic bag. Securely seal and label the bag (e.g., sample location, data and time sample was collected, and name of individual collecting the sample). Specimen containers and re-sealable bags may be pre-labeled to assist with sampling efficiency.
10. Dispose of the template, if used.
11. Remove outer gloves and discard. Clean gloves should be worn for each new sample.

Nelson-Jameson offers a wide variety of environmental sampling supplies to help you keep your program in top order. You can check out our Environmental Testing Solutions webpage here. We also have a new collection of scrub samplers from 3M™ to peruse here, that feature a metal detectable stick and a 96 hour hold time. For more information on environmental sampling, contact one of our product specialists today!

Sources:

Centers for Disease Control and Prevention. (2012, January 30). CDC – Surface sampling procedures for Bacillus anthracis spores from smooth, non-porous surfaces – NIOSH Workplace Safety and Health Topic. Centers for Disease Control and Prevention. https://www.cdc.gov/niosh/topics/emres/surface-sampling-bacillus-anthracis.html#.