Counting Calories & “Healthy” Chocolate


If you’ve ever wondered what 200 Calories look like on a plate, wiseGEEK has just the photo gallery for you! Meanwhile, scientists create a healthier chocolate by replacing fat with fruit juice. Read more

Dena Herman

Dena Herman, RD, PhD, MPH, is an Adjunct Assistant Professor in the Department of Community Health Sciences at the UCLA Fielding School of Public Health. Her research has focused on improving dietary quality among low-income populations, as well as the development of interventions to reduce childhood obesity.


What hooked you on science? On food?
My dad was a chef for Nathan Pritikin, a nutritionist and longevity research pioneer who showed that cardiovascular disease was reversible with diet.
The coolest example of science in your food?
I am not sure it is the coolest, but I have always been fascinated by gels and emulsions. For example, vinaigrette dressing: you take 2-3 liquids and simply by the order in which you mix them they become and emulsion, something thicker than what you started with. The same principle applies to a roux: dry + liquid + heat = creamy sauce. How cool is that?
The food you find most fascinating?
Injera (Ethiopian flat bread).
What scientific concept–food related or otherwise–do you find most fascinating?
Currently I am fascinated with the “-omics.” Genomics, epigenetics, nutrigenomics, etc., and the idea that we are what our grandmothers ate (the idea of life-course health development).
Your best example of a food that is better because of science?
I can’t think of one. I believe the best foods are whole foods that have not been “adulterated” by science, i.e. Frankenfoods.
How does your scientific knowledge or training impact the way you cook? Do you conduct science experiments in the kitchen?
I have two sons (9 years old and 12 years old). The kitchen is always an experimental station, whether trying new combinations of ingredients to create exciting colorful mixtures (questionably edible), or figuring out ways to make things explode.
One kitchen tool you could not live without?
Five things most likely to be found in your fridge?
Plain yogurt, cilantro, chili peppers, kale, raspberries.
Your all-time favorite ingredient?
Citrus, especially lemons and limes.
Favorite cookbook?
My German cookbooks. They take the simple and make it fabulous.
Your standard breakfast?
A kale, blueberry, and tofu shake. Phytonutrient-rich and protein ready.

Rachel Dutton

Rachel Dutton is a Bauer fellow at Harvard University where she uses cheese to study microbial ecosystems. She has collaborated with chefs David Chang and Dan Felder of Momofuku, and her research has been featured in Lucky Peach Magazine, The Boston Globe, NPR, The New York Times, and on the PBS TV series Mind of a Chef.

Rachel Dutton photo 2013Dutton Lab at JHF

What hooked you on science?
I blame microbes for hooking me on science. I am just completely amazed at how versatile and powerful they are—and we can’t even see them!
The coolest example of science in your food?
My lab studies how microbes form communities in cheese. I think the coolest thing is that these microbes are doing everything from fighting to sending out chemical messages, and all this is happening as we eat a piece of cheese.
The food you find most fascinating?
I guess I am biased, but I think cheese is absolutely fascinating. I started out thinking that cheese was this relatively simple thing, but the more I work with it the more respect and awe I have of how complex and nuanced it can be. Both in terms of the flavor and the science. It is also incredibly interesting from the perspective of its history and cultural significance, and there are so many passionate people working with cheese.
What scientific concept–food related or otherwise–do you find most fascinating?
I think the most fascinating food related concept right now is that microbes could be used as new sources of flavor in foods. Much of the flavor we currently have in fermented foods comes from the microbes themselves. And we know that microbes have an incredible diversity of metabolic pathways, so what if we found microbes that could ferment foods to give it totally new properties?
Your best example of a food that is better because of science?
Are there any analogies you like to use to explain difficult or counter-intuitive food science concepts?
The way that we identify species of microbes by sequencing their DNA can be a tricky concept. I like to compare it to matching fingerprints in a database, like in CSI, except that the fingerprints microbes have are unique sequences in their DNA.
How does your scientific knowledge or training impact the way you cook? Do you conduct science experiments in the kitchen?
I think I use both cooking and science to explore and learn. In the lab, I use science as a way to learn more about the way microbes behave. In the kitchen, I like to cook things that allow me to explore new cultures or ingredients.
One kitchen tool you could not live without?
I use a scale a lot. Even when I don’t need to, sometimes I’m just curious how much something weighs.
Five things most likely to be found in your fridge?
Whole milk yogurt, lemons or limes, maple syrup, mayonnaise, and ginger.
Your all-time favorite ingredient?
I think steamed clams are my favorite food, and fermented black soybeans are a favorite ingredient. I’m also a sucker for anything with cardamom in it.
Favorite cookbook?
When I have time on the weekends, sometimes I’ll cook from Rick Bayless’ Mexican Kitchen. I grew up in California and studied for a while in Mexico, and I love Mexican food and culture, especially from central and southern Mexico. The other cookbook I’m really enjoying right now is Yotam Ottolenghi’s Plenty.
Your standard breakfast?
I usually rotate between yogurt with honey and granola, oatmeal with maple syrup and walnuts, and eggs on toast.

Stilton Cheese & The Human Microbiome


With all this talk of Human Cheese, we’re thinking—and reading!—a lot about the microorganisms in cheese and in our bodies. In this week’s round-up, researchers discover “secondary flora” that contribute to Stilton’s unique smell, and Michael Pollan investigates our symbiotic relationship with the microbes within us. Read more

Human Cheese


Have you ever been offered a fancy cheese that smelled more like a used gym sock than something edible? Odor artist Sissel Tolaas and researcher Christina Agapakis took this idea and ran with it, with their project Synthetic Aesthetics. The duo used bacteria isolated from human hands, feet, noses, and armpits to generate cheese!

Many cheeses, like beer, wine, and yogurt, are the product of fermentation. Fermentation occurs when microorganisms such as yeast and bacteria convert carbohydrates such as sugar into alcohols, gasses, and acids to generate energy in the absence of oxygen. One common cheese-making type of bacterium, Lactobacillus, breaks down lactose, the primary milk sugar, to lactic acid. This results in lowering the pH of the milk, which as pointed out in a previous post, causes coagulation and solidification into cheese. The work of microorganisms in cheese also results in the creation of many other byproducts that give cheeses their unique smell, texture, and flavor profiles. For example, the bacterium, Propionibacterium freudenreichii, generates carbon dioxide gas in the process of making swiss cheese and causes its characteristic holes [1]. Penicillium roqueforti, which is related to the fungus that helps produce the antibiotic, penicillin, gives blue cheese it’s distinct aroma and look [1].

Microorganisms that use fermentation are found everywhere. Tolaas and Agapakis realized that the human body shared many characteristics with the environments for creating cheese. On a hot day or before a hot date, your armpits may be just as warm and moist as an industrial cheese incubator. Furthermore, cheese-making bacteria like Lactobacillus are common inhabitants in the mammalian gut [1]. With this information, they isolated bacteria from hands, feet, noses, and armpits and added them to whole milk to serve as starter cultures.

Figure 1. (A) Swabs from various human body parts incubating in raw milk. (B) Cheeses after solidifying. While no cheeses were consumed, they were evaluated with an odor survey and by DNA sequencing to identify the bacteria cultures present in each cheese.
Figure 2. Samples prepped for the smell survey. Participants of the survey were asked to smell the samples and provide a description of the odors they detected.

Here are the results:

Source Bacteria Isolated Odors
Hand-1 Providencia vermicola
Morganella morganii
Proteus mirabilis
yeast, ocean salt, sour old cheese, feet
Foot-1 Providencia vermicola
Morganella morganii
Proteus mirabilis
sweat, big toe nail, cat feet, sweet, milky, orange juice in the fridge too long, fungus, buttery cheese, soapy, light perfume
Armpit-1 Providencia vermicola
Morganella morganii
Proteus mirabilis
Feta cheese, Turkish shop, nutty, fruity, fishy
Nose-2 Providencia vermicola
Morganella morganii
Proteus mirabilis
cheesy feet, cow, cheese factory, old subway station, toilet cleaner
Armpit-2 Enterococcus faecalis
Hafnia alvei
neutral, perfumed, industrial, synthetic, fermentation, car pollution, burning, sharp, chemical
Armpit-3 Micobacterium lactium
Enterococcus faecalis
Bacillus pumilus
Bacillus clausii
neutral, sour, floral, smooth, yogurt
Foot-5 Providencia vermicola
Proteus mirabilis
yeast, jam, feet, putrid, sour, rotten
Armpit-4 Enterococcus faecalis yogurt, sour, fresh cream, butter, whey

The cheeses displayed a diverse range of bacterial species and odors. Interestingly while some cheeses smelled like “old subway station” or “cat feet,” others exuded the familiar & appetizing flavors of “yogurt,” “feta cheese,” and “light perfume.” Furthermore, some of the bacteria isolated were common to various cheeses. For example, Enterococcus faecalis is a lactic acid bacterium found in raw milk and cheeses, like farmhouse cheddar varieties [2]. Proteus mirabilis is related to Proteus vulgaris, which is responsible for giving surface-ripened cheeses like Limburger and Munster a strong aroma [3].

While these bacterial cultures may not serve as the basis of a new type of artisan cheese, Agapakis notes:

“These cheeses are scientific as well as artistic objects, challenging us to rethink our relationship with our bacteria and with our biotechnology. . . . The cross-over between bacteria found on cheese and on human skin offers a tantalizing hint at how our bacterial symbiotes have come to be part of our culinary cultures.”

In the face of diminishing resources, we are reminded that untapped reservoirs, which may be literally under our noses, might contain hidden treasures that could change the way we generate and produce food.

Online Resources

  1. More about this project
  2. More about Christina Agapakis
  3. More about Sissel Tolaas
  4. More about bacteria found on the human body
  5. More about the basics of cheese making

References cited

  1. Agapakis, C. 2011. Human Cultures and Microbial Ecosystems.
  2. Gelsomino. R. et al. 2002. Sources of Enterococci in Farmhouse Raw-Milk Cheese. Applied and Environmental Microbiology 68(7): 3560-3565.
  3. Deetae. P. et al. 2009. Effects of Proteus vulgaris growth on the establishment of a cheese microbial community and on the production of volatile aroma compounds in a model cheese. Journal of Applied Microbiology 107(4):1404-1413.

Vince ReyesAbout the author: Vince C Reyes earned his Ph.D. in Civil Engineering at UCLA. Vince loves to explore the deliciousness of all things edible.

Read more by Vince Reyes

Jeff Potter

A science and food geek, Jeff Potter is the author of Cooking for Geeks: Real Science, Great Hacks, and Good Food, which the Washington Post called “one of the most useful books on understanding cooking.” He can be seen on TV engineering the world’s largest donut and is currently obsessed with the science of beverages. Check out more of Jeff’s food geekery at

photo by John Zich, courtesy of

photo by John Zich, courtesy of |

What hooked you on cooking? On science?
I find it intensely gratifying to understand how things are made, and science really is about understanding how systems work and behave. Everyone eats, and almost everyone cooks, and the science behind both fascinates me. Plus, every time one steps foot into a kitchen, it’s inherently a science experiment, even if you don’t think about it that way. The amount of science that goes into the morning cup of coffee alone would shock most people. Plus knowing some science behind what you’re doing in the kitchen is one of the best instructors.
Five things most likely to be found in your fridge?
Eggs, yogurt, kale, hot sauce, beans.
One kitchen tool you could not live without?
A good sauté pan. Even a non-stick one. Really, you can get by without much at all, but one decent pan changes everything.
Favorite cookbook?
I was given a dessert cookbook years ago that was an anthology of sorts: one recipe from each of the top pastry chefs in the country. No pictures, not glossy, just a few lines on the chef and then the recipe. Every single recipe I made from that book came out amazing, and every single recipe managed to teach a new concept or idea. I don’t know if it’d stand up very well against all the food porn books that have now come out, but that book (given to me by a chef friend) was amazing for me.
The scientific concept—food related or otherwise—you find most fascinating?
That only a few basic building blocks—hydrogen, carbon, oxygen, nitrogen, and ok, fine, sulfur—are responsible for everything from bars of chocolate to a toucan flying around a rainforest in South America. The difference in complexity just one level up (molecules) from what seems so simple (atoms) is staggering; and then to consider that there are multiple layers up above that until we get to your brain understanding these words… mind-blowing.
The coolest example of science in your food?
You can tell where a tomato was grown—well, at least the latitude—by the ratio of various isotopes in it. It sounds crazy, but rainwater is not “pure” H2O; or more precisely, there are different isotopes of the “O” in “H2O” and the lighter one, 16O, is more likely to evaporate then the heavier one (takes less energy for it to take off). As you go toward the equator, evaporation rates in rainfall go up (it’s warmer, after all), so tomatoes grown toward the equator have higher concentrations of the heavier isotope 18O. The neat thing is that that ratio sticks with the food all the way down to the jar of fancy imported Italian pasta sauce, so you can semi-reliably tell where in Italy the tomatoes were grown if you look at enough of the various isotopes and minerals in it.
Your all-time favorite food ingredient?
I don’t really have a favorite food ingredient, but nothing beats fresh fruit at the peak of its season.
The food you find most fascinating?
Can I go with “beverages” as a general category? Everything from green tea to beer is amazingly complicated. Most food ingredients—apples to flour—are relatively unchanged from their “as-grown” state, but drinks are an entirely different category, as they’re entirely constructed.
Are there any analogies you like to use to explain difficult or counter-intuitive food science concepts?
Breaking of secondary and tertiary bonds in protein denaturation can be a bit confusing, as the “simple” model people have for molecules is that they’re made up of such-and-such atoms, without regard to the shape that the molecule takes impacts how it functions. I’ll sometimes describe the molecule as like an old-fashioned telephone cord (did I just date myself?), where the cord can twist up, kink, and tangle on itself.
Your best example of a food that is better because of science?
The egg. The amount of agricultural science and gains in productivity that have gone into chicken eggs in the past 100 years is just amazing. If the same “gains” had been made in humans, Olympic sprinters would be running at 65 miles per hour…
Your standard breakfast?
Depends on the time of year and where I am. Right now, in New England’s winter, yogurt with muesli, and then sautéed red onion, kale, garlic, two eggs, and a squeeze of lemon juice on top. If I feel like spending more than the two minutes it takes to make it, maybe some grated cheese on top.
How does your scientific knowledge or training impact the way you cook? Do you conduct science experiments in the kitchen?
I only cook on an amateur level, for myself and my friends; so for me cooking is a very ad-hoc thing, without too much fuss or worry about taking good, exact notes—but this is only because, generally speaking, I don’t need reproducibility of an entire dish! But I do perform little mini-experiments each time I cook. Take tonight (it’s after dinner as I write this)—I’ve been wondering why the tofu I’ve been cooking keeps sticking to the pan. It’s a stainless steel pan, and I put some oil in it—but it always seems to stick after it gets up above a certain temperature. I’m guessing it’s steam from the tofu pushing the oil away from the surface of the pan; and then the proteins in the tofu stick to the pan (and do not seem to release even when browned). I’ll probably kick myself later for writing this, as I’m guessing the “why” is simple here, but I was wondering if low heat versus high heat makes a difference… so I tried changing just that. Nope; still sticks. That’s the type of “mini” experimentation I love to encourage in the kitchen, because it doesn’t take any extra work to do it, beyond thinking about it.

Emulsions & Food Engineering


Rutgers Professors Rick Ludescher and Mukund Karwe explain the basic chemical principles of emulsions and introduce food engineering techniques like extrusion and high-pressure processing. If you’ll be on the East Coast this fall, be sure to check out Rutgers’ crash courses in food science and food safety. Read more