Friday, May 31, 2013

Students and biology professor aim to rid compost of deadly bacteria

A group of Randolph researchers hope to save lives by fighting bad cheese bacteria with good cheese bacteria.

The bad cheese microorganism is Listeria monocytogenes, which is dangerous and potentially deadly to the elderly, children, and pregnant women, and is sometimes found in soft cheeses. The good cheese bacterium is Lactococcus lactis, which is used to make cheddar cheese. They are studying whether putting Lactococcus lactis in compost will kill any Listeria and make the fertilizer safer to use.

Meron Demeki ’15 probes the temperature of compost.
“Municipalities and commercial entities are starting to get into mass composting,” said Adam Houlihan, a Randolph College biology professor. “If that compost becomes contaminated with some sort of food-born pathogens, those could possibly contaminate produce grown with the compost.” That contamination could result in more illness and death.

Houlihan asked Elizabeth Delery ’14 and Meron Demeke ’15 to work with him on this research project.

They turned four trash cans into composting bins and filled each with compost. One bin contains only the compost, while another contains the compost and Listeria (although a non-deadly form). The other two contain compost, Listeria, and different forms of Lactococcus lactis. Their theory is that the lactic acid and nicin produced by the Lactococcus lactis will help kill the Listeria.

Each day, the research team takes the temperature of each batch of compost. They also take samples to test for acidity and bacteria levels. Within a couple of weeks, the data should show hints about the validity of their theory, but Houlihan said the research will continue throughout the summer.

Elizabeth Delery ’14 prepares to streak a petri dish.
Delery has already started another research project with Houlihan to investigate a cancer treatment idea that she had. She said the compost research has helped her to develop laboratory skills that would be useful in her desired career as a medical doctor or in other careers she may choose. “I enjoy the research and the hands-on experience with lab techniques,” she said.

Demeke, who is weighing the options of attending medical school or pursuing a Ph.D., looks forward to finding out whether their method of killing Listeria works. “If we succeed in what we’re doing, we’ll be saving lives, which is the ultimate goal,” she said.