Years ago I took a microbiology class to fulfill the requirements for a degree. It was specifically designed for students like me, arts majors who needed those crucial science credits. As such, it stayed away from “serious” biology and focused more on the societal impact of microbiology. From infectious diseases to the misuse of antibiotics and anti-bacterial soap, it was an interesting, if somewhat frightening class. We also discussed the more benign and beneficial aspects of microbes, chief among them their ability to aid in the production of various food and beverages. It made me realize how indebted we are to these little critters, and how many of my favorite edibles and imbibables would not exist without their help. A few examples:
- Cheese: Bacteria produce lactic acid, which initially thickens the milk; bacteria also determine the flavor of the cheese later in the ripening process. For examples of the types of bacteria used to make different cheeses, go here.
- Beer: Yeast (Saccharomyces cerevisiae), once added to the wort, a liquid made of barley, hops, sugar and water, converts the sugar in the wort to alcohol and carbon dioxide (creating bubbles in the beer)
- Bread (leavened): Also made using yeast, although the byproducts of the yeast’s fermentation of the dough are water and carbon dioxide (not alcohol), which fills the dough with air bubbles that make it rise
- Wine: Like beer, wine is made using yeast, but instead of hops and barley, the starter material is obviously grapes
- Pickles: Cucumbers are fermented using lactic acid producing bacteria, giving pickles their sour taste and also preventing harmful strains of bacteria from taking hold. Microbes used: Enterobacter aerogenes, Lactobacillus brevis and L. plantarum, Leuconostoc mesenteroides, Pediococcus cerevisiae, Enterococcus faecalis
- Olives: Basically inedible until they are fermented, olives are also fermented using lactic acid producing bacteria, including Lactobacillus brevis, Lactobacillus plantarum. and Leuconostoc
- Yogurt: Bacteria added to milk produce lactic acid that makes the yogurt sour and partially breaks down the lactose in the milk. Microbes used: Lactobacillus bulgaricus and/or acidophilus & Streptococcus thermophilus