Bill Hanage, associate professor of epidemiology

Bill Hanage, associate professor of epidemiology

Off the cuff: Bill Hanage

Fall 2011 ]

Why are we seeing so many deadly new forms of E. coli in our food?

“Bacteria are a bit like a Mr. Potato Head®. You have the core DNA—which is the potato—and then onto that are stuck all kinds of other genes that help it adapt to its niche. In bacteria, the promiscuous interchange of genes is happening all the time, so new combinations constantly emerge. And our globalized food chain helps new combinations of genes to reach and colonize new niches. People often say, ‘Bacteria are a primitive life-form.’ No, they’re not. They’ve been around longer than we have and they’ll be around after we leave. It’s estimated that the number of bacterial cells on the planet is five times 1030—that’s a 5 followed by 30 zeroes. To put that in context, that’s more than the number of stars in the known universe. So in terms of our knowledge of bacteria, we haven’t scraped the tip of the iceberg, not even the thin sheen of ice melt in the midday sun on the top of the iceberg. We’ve seen maybe the top few layers of molecules about to evaporate. Causing foodborne disease is not the primary function of E. coli. It’s just that we tend to notice that quality in them. We’re humans, we’re self-centered, and what happens to us is the most important thing in the world.”