Q&A: Author John Ingraham knows his microbes

March of the Microbes
Sighting the Unseen by John L. Ingraham
scanned cover

John Ingraham is on a first-name basis with microbes of all designs and “intentions” – the good kind and the bad kind.

You’d do yourself a favor getting to know microbes, too. They’re invisible but ubiquitous, directly affecting us and our world: human illness and well-being, the planet’s atmosphere, its geology and oceans, the food chain and, of course, that bottle of Champagne you popped on Valentine’s Day.

As the author of “March of the Microbes: Sighting the Unseen” (Belknap Press of Harvard University Press, $28.95, 336 pages), Ingraham offers a rare thing – novice-friendly science.

Ingraham retired in 1990 from the University of California, Davis, where he spent his career as a researcher and teacher in the departments of viticulture and enology, and microbiology.

In the book, he discusses the microbial world’s impact past and present – for instance, he speculates on the likely origin of cheese- making and explains how clouds over the oceans are formed. On a larger scale, he takes us to the limestone caves of Carlsbad Caverns National Park in New Mexico, traces the life cycle of lichens and speculates on the cause of the dinosaurs’ extinction.

Ingraham is an avid hiker who keeps chickens in the yard of his Fair Oaks home. He is writing a biography of Davis wine pioneer Maynard Amerine and is a frequent contributor to Wines & Vines magazine.

We can’t see microbes with the naked eye, but we can see their effects. Examples?

The leaves that drop … in the fall aren’t around by the next year because microbes have consumed them and converted them into better soil. And grass is green because it’s fertilized with nitrogen, much of it supplied by the activities of microbes.

What familiar foods do microbes make possible?

Bread is overwhelmingly microbial, and all fermented things – wine, yogurt, soy sauce, pickles, sauerkraut. Given microbes’ contribution to the growing of plants and animals, you’d have to say they make all foods possible.

When it comes to our personal health, can we encourage the presence or growth of so-called good microbes in our bodies?

The actions of microbes on the foods we eat certainly add some nutrition to our diets. An age-old issue that remains somewhat controversial is foods such as yogurt. … Does yogurt help (the human digestive system)? You can get arguments on both sides.

How can we avoid contact with bad microbes?

Most microbes that are going to hurt us are from other humans. So it’s contact from humans to the food and then to us. Certainly if we’re going to can foods (at home), we must make sure we’ve killed the microbes that can make toxins. Tomatoes aren’t (difficult), but green beans can be a real problem.

Is there anything in which microbes don’t play a role?

It gets tough when we start thinking about where we get the beginning materials (to make things). For instance, the chemical industry is based on sulfuric acid; it’s the thing that most things started from way, way back in the synthesis. And we got the sulfur from the activity of microbes.

What’s the last word on microbes?

We have to remind ourselves that if it weren’t for microbes, we would not be here at all.