Although we’ve always known that we’re supposed to wash our hands and keep our surroundings clean, it’s definitely fair to say that it was much easier to do these things half-heartedly before the emergence of the COVID-19 pandemic.
And in addition to giving us a clear and present reason to stay on top of our hygiene practices, it’s also made us a lot more conscious of the surfaces we touch every day. While we may have previously guessed that the more public of these surfaces run the risk of making us sick, it’s obviously a much greater concern now.
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And it’s likely this new context and the critical importance of grocery stores in the wake of the pandemic that have led to the popularity of one up-and-coming scientist’s TikTok experiment.
Before we get into what this person did, there’s one term that we need to define out of the gate.
![Image credit: Reddit | [deleted]](https://static.diply.com/bJ3UsA4EOrQ4e9HH8N3d.png)
Although we’re familiar with bacteria, it’s worth going over how a bacteria colony typically forms.
As the journal Molecular Cell Biology outlined , bacterial colonies form when one bacterium cell clones itself repeatedly, which takes the form of a larger structure of cells like the one we see here.
Many of them are smaller and they tend to vary in form, but this is nonetheless a bacterial colony.
And it was these colonies that a PhD candidate at McGill University named Dilhan Perera was on the hunt for when he stepped into his local grocery store.
In a video posted on TikTok, he set out to determine how much bacteria he would be able to isolate from various products and surfaces at the store.
To do this, he swabbed each surface and deposited the collected microbes into a nutrient-rich “broth” known as LB Agar that is used to culture bacteria in lab environments.
Once he returned to the lab, Perera incubated his samples for 48 hours at 37 degrees Celsius (98.6 Fahrenheit), which makes it easier to visualize what kind of colonies could blossom from them.
Now that we’ve gone over Perera’s process, let’s see what he tested and how much bacteria he found on them.
Due to its placement out in the open, he started with an apple in the produce section. As he determined in his follow-up video , this apple would end up providing the building blocks for 32 bacterial colonies.
Once he shared this fact, he reminded viewers that both the CDC and the FDA recommend washing fruits and vegetables with water before use to prevent foodborne illnesses.
Next, he went to one of the store’s refrigerated areas and swabbed a milk carton.
Interestingly, although it’s only slightly less out in the open than the apple was, the milk carton only yielded enough for two colonies.
But the biggest bacterial load was yet to come.
After the milk, Perera decided to take a trip to the meat section and swab a package of beef that had been placed that day.
Once this sample was incubated, over 300 colonies appeared in the LB Agar.
Perera also noted in his follow-up that the colonies featured a wide variety of white and yellow colors, which suggested that the sample held a diverse array of bacterial species.
Such a rich bacterial profile illustrates why we have to cook meats according to minimum internal temperatures. It also explains why Gordon Ramsay yells about cross-contamination whenever he catches a chef storing raw meat next to cooked meat.
In addition to these products, he also swabbed the door handle on one of the freezers as well as the handle on his shopping cart and the card reader at the checkout.
And it turns out that the freezer door yielded five colonies, while the cart’s handle only resulted in one. This told Perera that these surfaces were being properly sanitized according to COVID-19 safety guidelines.
Although the card reader sample only formed six colonies, he found that these were larger than usual and one of them even featured a “small 3D mound.”
Unfortunately, it seems we’ll have to wait before we get a fix on which bacterial species he uncovered as he’s planning to address that in a third video.
Perera’s initial video that featured him swabbing the surfaces has garnered 3 million views at the time of this writing, while the follow up has netted him over 838,000 views.
And while Perera wanted his videos to encourage good food safety practices and provide a little insight into his research practices, he stressed that they’re not meant to make people scared of bacteria.
As he told Buzzfeed, “According to the NIH, less than 1% of bacteria actually make us sick. The takeaway from this video is that bacteria are all around us and people should practice proper hygiene, especially with food.”
Perara’s first video can be seen here while his follow-up is available here .
