This past Saturday, my wife picked ‘Frozen’ for movie night (no, we don’t have kids). In the movie, one of the main characters was born with the power to freeze her surroundings, which she struggles to control. By the time, ‘Let It Go’ was playing, I couldn’t help but wonder how the repeated freezing of the castle was impacting the indoor microbiology, which led to Google Scholar (I am a terrible movie watcher) to investigate what we know about the microbial ecology of refrigerators and freezers.
The amount of cold storage we use is staggering (at least to me) — the USDA reports that the US has ~4 billion cubic feet of refrigerated storage. Searching for information on the microbial ecology of refrigerators is difficult – imagine how many studies use some formation of the word ‘refrigerated’ or ‘frozen’ when referring to sample storage and processing. However, The microbiology of psychrophiles (cold-loving microorganisms) dates back to at least 1902, when Schmidt-Nelson coined the term ‘psychrophile’. Psychrophiles include members of the genera Pseudomonas, Psychrobacter, Staphylococcus, Photobacterium, and Halomonas, among others. The biology behind these microbes is fascinating (anti-freeze proteins!) and they are widely distributed in the environment. Almost all psychrophile ecology research that I was able to identify investigated the impact on food storage and spoilage — however I can’t help but wonder about the microbial ecology of the refrigerated spaces themselves. I’m starting the search in the back of the grad student lunchroom fridge.