A lack of bread leads to a lactic acid bacteria in our homes

24 I Biology A lack of bread leads to a lactic-acid bacteria in our homes

BY GABRIELLE HERNANDEZ, BIOCHEMISTRY, 2023 DESIGN BY KATIE GREEN, BIOENGINEERING, 2022

Bread has always been a staple

to humanity when it comes to

times of crisis. The infamous pictures of bread lines during the Great Depression demonstrated the weight of the economic downturn in the United States. With an unemployment rate of about 25 percent, many people turned to local food banks and churches for bread and soup. This is not dissimilar to the winding lines of cars at food banks as a result of the current global pandemic.

Now, as the general public finds ways to entertain themselves in their own homes, many have turned to learning the art of baking bread at home. So much so that, along with toilet paper and basic cleaning supplies, flour has of yeast and bacteria that naturally seemed to fly off the shelves. Forbes leavens sourdough bread. Sourdough reported that King Arthur, America’s is aptly named for the sour taste of oldest flour company, experienced a the bread produced by the lactic acid 287 percent increase in March sales bacteria, but varying species of bacteria of its high-protein bread flour, a key and yeast impart a unique flavor and ingredient in producing the gluten smell to every loaf. The varying species that gives bread its distinct chewiness. Along with flour, dry-active and instant yeast have also seemed to disappear from shelves, motivating more people to take part in growing “ The varying species in starters can originate their own yeast at home, which has led to bread-making becoming a popular from dust in the air, trend. Northeastern students are well the container it’s kept involved in the craze. Liz Gmoser, a fourth year mechanical engineering in, and even the hands major, commented, “I started my starter because apparently I am one of the that first form the people who ‘if my friends were jumping starter.” off a bridge, I would too’ because all my friends were doing it and I wanted to try as well. Pierre, named because when all his little bubbles pop it’s like in starters can originate from dust in the he’s peeing air, is unique because he’s air, the container it’s kept in, and even a sturdy starter willing to put up with the hands that first form the starter. my sporadic feeding schedule. It’s been In fact, this diversity is so integral to a fun quarantine journey, and he’ll be sourdough that a lab out of North coming back to Boston with me.” Carolina State University has made it their mission to track starters through “Starter” refers to a base mixture of flour a citizen science project. Participants and water (other ingredients can be send in their starters, and Professor added as well), that supports a culture Rob Dunn’s lab uses DNA sequencing to identify species across the Silva Database, a database of ribosomal RNA sequences. Now, they have built an interactive map of their participants showing the most common strains of yeast and bacteria in the starters of those regions. They have also performed an experiment correlating the bacteria on a select number of baker’s hands and their starters, showing the symbiotic relationship between our microbiome and the microbiome of the world around us (or the world of bacteria in a jar of starter).

Ultimately, many in quarantine have gained new skills and new behaviors in this momentary interruption of daily life. One of those skills has become baking, a historic tradition for human beings around the world. Culturing a sourdough starter is an excellent example of creative survival when the shelves are emptied of bread and yeast, and it has created a community of bacteria, yeast, and humans alike.

Trends in Food Science and Technology (2005). DOI: 10.1016/j.tifs.2004.02.012 American Society for Microbiology (2020). DOI: 10.1128/mSphere.00950-19

PHOTOS BY GABRIELLE HERNANDEZ