Tales from the Lab #1: The Coffee Mold

I’ve been wanting to do something “fun” for my blog for a while now, something that isn’t necessarily related directly to my books and I came up with this idea a few days ago. As some of you know, I’m a microbiologist by profession, though a writer at heart. Bringing both of these things together, I present to you “Tales from the Lab” (names have been changed to protect the identities of those involved).

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Steven liked his coffee, particularly from Starbucks, but often became so busy he failed to finish drinking it. One particularly busy Friday, which also happened to be the day before he left for a two-week vacation, he was able to finish only a third of his daily cup before being interrupted by his manager to discuss the state of a report that needed to be finished. The coffee was moved aside, pushed to one corner of Steven’s desk, and promptly forgotten.

            Steven finished the report before departing that day, though his thoughts were focused solely on the upcoming vacation. He had been saving up his paid time off for this trip and was eager to be done with the workday. The coffee, left unfinished, remained on the corner of his desk where it sat alone and forgotten for another ten days.

            On that fateful tenth day, one of Steven’s co-workers, Mara, paused near his desk while searching for a document he had been working on prior to his long-awaited vacation. She noticed the paper coffee cup sitting on the corner of the desk, and was immediately struck by its strange new contents. A thin layer of white, fuzzy mold had appeared on the surface of the cold, bitter liquid. Rather than becoming disgusted by the discovery on Steven’s desk, she was intrigued and immediately did the only logical thing one does in such a situation: she contacted the resident microbiologist (me) and asked for an emergency identification on the coffee mold.

            As luck would have it, I had the necessary growth media in the lab and time enough to take a sample of the coffee’s fluffy growth to proceed with Mara’s request. Steven’s coffee mold, as the sample became known, was transferred to an agar plate and placed in an incubator for a few days.

Given the proper growth conditions, Steven’s coffee mold thrived and took on a new life of its own. It spread across the agar plate, transformed itself from fluffy-white to velvety-green, and within a week it was ready for me to perform the identification that had been requested.

Identifying molds, as long as one isn’t looking for speciation, is a rather old-school type of laboratory work. It doesn’t require much in the way of fancy equipment—only an incubator to grow the culture, a microscope, some tape, a drop of blue dye, and a glass slide. I put a drop of the blue dye onto the slide, then took a piece of clear tape and pressed it onto the mold culture. The tape picks up both spores and hyphae by doing this, but it’s the spores (conidia, if you want to get technical) that allow me to make the identification. The tape was then placed across the dye on the slide, and the slide placed under the microscope. It was time to learn what sort of mycological monster had been brewing in Steven’s forgotten coffee.

The spore structures were immediately recognizable to me as belonging to the genus Penicillium, named as such because the structures resemble tiny paint brushes. Molds from this genus produce the antibiotic penicillin, and are common environmental contaminants.

The microscope in my lab happens to have a camera attached to it, so I snapped a quick photo and sent my findings to Mara. She was delighted to know the results of my test, and was eagerly anticipating Steven’s return to the office. Mara liked to tease her friends, and this would give her some new ammunition when it came to Steven. (He found the whole scenario quite funny when it was revealed to him, and later asked jokingly if I might identify some of the things he’d found growing in his refrigerator, too.)

Not all of my workplace experiences have been relaxed enough to allow for the sort of silliness that was described above, but it is these sorts of interactions with other coworkers that are memorable and make work fun. Not to mention that looking at mold under the microscope is one of my favorite things to do in the lab; each type of mold is unique and fascinating in its own way. This study was particularly memorable because I don’t often get the opportunity, or have the time and resources, to work with samples that come from sources like Steven’s coffee.

            I hope to write more Tales from the Lab in the future, but in the meantime, remember that even the strongest coffee, if left forgotten, can take on a new life of its own in the form of a fuzzy, white mold.