December 18, 2013
From the Mail Bag: Cleaning your Workspace
- Food Safety
Here’s an email I recently received:
We’ve just established a small microbiology lab at our fish processing plant. We are transitioning from using an outside lab to running tests in-house. What’s the best way to make sure our lab stays clean and decrease the chances of the cross-contamination that I’ve heard so much about? What should we use to clean, and how often should we clean? Where should we focus our efforts? Thanks for your insight.
Dale W., Baltimore, MD
Hi Dale W.,
It may sound banal, but a major part of maintaining a microbiology lab means keeping it clean. When it comes to maintaining good laboratory practices, it’s a good idea to follow a few rules of thumb:
1. Prioritize your space
Just as in your production plant, there are some surfaces that are more important to keep clean than others. Keeping the deli slicer on the production floor spic and span is probably more important than the printer in the offices. Microbiology labs are like this, too. There are some surfaces—the lab benches, sinks, etc—that should be cleaned more often than others. I call these kitchen counter surfaces: the places where things get done. These surfaces need to be cleaned after every experiment, or daily at a minimum.
The other areas in the lab I like to call dust collectors: these are areas like the top shelf that holds all the unused glassware or the top of the fridge. These places don’t do much more than collect dust. Before you write these places off as unimportant, consider this: each single dust particle could be home to up to 22 bacterial cells. Cleaning these surfaces routinely—scheduling can depend on the accessibility of the surface and the size of the lab—can help to maintain a more efficient lab.
2. Bleach first, then alcohol
Now that we’ve discussed what to clean, let’s talk about how to clean it. While there are many commercial products out there for industrial lab cleaning, studies suggest that among the most effective solution is a basic two-step process: first bleach, then wipe down with ethanol.
To make the two solutions, first get two spray bottles. In one mix 1 part bleach (the stuff from the grocery store is fine) and 9 parts water. In another, mix 3 parts water and 7 parts ethanol. Give them a good shake to mix them thoroughly, then you’re ready to start cleaning.
Clear the benchtop of any stray equipment, start with spraying down the countertops with the bleach solution. Give it a good wipe down with some paper towel. The bleach will kill any live cells, as well as destroy any proteins or DNA that might be present on the benchtop. Let this sit on the countertop for a few minutes to give the bleach time to work. The next step is to spray and wipe with the ethanol solution. This cleans off the bleach residue, as well as helps the countertop dry faster.
A small disclaimer: please remember to wear gloves and protective gear while cleaning. I don’t have to remind you that bleach, well, bleaches. No one wants to ruin their favorite sweater (this is from experience!!).
Oh and don’t forget the floors! These should be mopped regularly (at least weekly) with a commercial antiseptic cleaning solution according the manufactures instructions.
3. Spread the responsibility
We’ve covered the what, when, and how, and now to the who. In all reality, it’s everyone’s responsibility to make sure the workspace is clean. Many labs have some sort of schedule they maintain that spreads the responsibility of keeping everything clean among the lab personnel by day, week, or month. This helps to ensure that the lab gets cleaned regularly as well as develops a sense of ownership for the personnel.
4. Tools get dirty, too
When you’re cleaning the benchtop, remember: tools get dirty, too. That pipet you were using for that last experiment needs to be cleaned just like the benchtop does. After every experiment, be sure to wipe down the instruments you used with a bleach-soaked paper towel and set them out to dry. Also don’t forget about things like drawer handles, bottle caps, etc.
While this may seem like a lot of work, it’s really pretty easy once you get in a good routine. And most importantly, keeping your lab clean will ultimately help you run a more efficient and safer laboratory as well as help ensure your results are accurate, which keeps everybody happy.
Lauren Bambusch is a microbiologist by trade as well as a writer and baker by hobby. She lives in Baltimore with her husband, two cats, a super-sized mutt, and a school of fish, all of whom root for her Alma mater, Michigan State. Go Green!