‘Human cheese’ from celebrity skin bacteria

Posted on June 7, 2019 by Douglas Powell

Of course Heston I-didn’t-sicken-550-people-wth-Norovirus Blumenthal would be vain enough to sign up to have cheese made from his skin – his groin area.

I’m a big fan of fermentations but am also a big fan of using knowledge and experience to improve on basic biological phenomena.

Bettina Makalintal of Vice writes that people have been fermenting for at least 9,200 years, and yet, not everyone’s convinced. The process requires bacteria, which can result in funky sights and smells, squicking some people out. Still, it’s safe to say that fermentation advocates have done a good job of turning people on to the magic of microbes: dry-aged beef is on high-end restaurant menus, and more and more people reap the illness flavor rewards of raw-milk cheese.

A new exhibit at London’s Victoria & Albert Museum called “Food: Bigger than the Plate” shows off not only a toilet made of cow manure and an edible water bottle, but also “human cheese.” The latter is made using human bacteria. And not just any human bacteria, but celebrity bacteria

Most cheese is made using starter cultures, bacteria that curdle the milk, and often, those starters come from a packet. For the V&A’s five “human cheeses,” however, that bacteria came from celebrities, who had their skin swabbed in the name of science and truly funky cheese: from baker and food writer Ruby Tandoh to chef Heston Blumenthal to Blur’s Alex James, a cheesemaker himself. (British rapper Professor Green and Suggs of the ska band Madness also contributed.) It’s “like a celebrity selfie in cheese form,” reads V&A’s blog.

The point, the museum says, is to challenge people’s “squeamishness” and to enhance “our appreciation of the microbial world.”

Fun with fermentations: Drunk raccoons

Posted on February 24, 2019 by Douglas Powell

My 10-year-old daughter asked me today, what are yeast?

I started into one of my typical speeches about the difference between prokaryotes and eukaryotes, the role of the nucleus and fun with fermentations.

We have some basic microbiological work to do, and the French professor reminded me I was talking to a 10-year-old.

I reminded the French professor she should stick to French.

But if I’m going to teach her hockey basics, I guess I can teach her some micro, and she can teach me about art (she’s really talented; and that applies to both mother and daughter).

Hockey player and veterinarian, Scott Weese of the Worms and Germs blog, writes that rabies and distemper are the two things that come to mind first when a raccoon is acting strangely. Rabies is a big concern because it can also be transmitted to people. Distemper is also a viral infection, caused by canine distemper virus, and is transmissible to dogs and some wildlife species, but is not zoonotic. Raccoons are very susceptible to distemper and infections and outbreaks are common. If raccoon rabies is present in the area, we need to err on the side of caution and treat an abnormal raccoon as potentially rabid until proven otherwise. If raccoon rabies isn’t in the area, an abnormal raccoon is generally assumed to have distemper (but rabid raccoons can hitch rides on vehicles, so we can’t rule out rabies completely without testing).

But there is one other possible cause for a raccoon to be acting somewhat drunk… alcohol.

A story from last fall (yes, I’m a bit slow) in the Washington Post describes a rabies scare in West Virginia, where the raccoons were ultimately determined to have been intoxicated by alcohol. No, they hadn’t raided a liquor store – it turns out they’d been eating fermented crab apples.

Surprisingly (and good to hear), they weren’t euthanized right away because of their abnormal behavior. Just like we do for any other drunken mammalian species, the raccoons were held until they sobered up, and were then sent on their way. A picture of one of the young offenders was released by the Milton (W. Va) Police Department. It’s much cuter than the typical mug shot.

Drunk or not, it’s still a good idea to stay away from raccoons, especially in southern Ontario.

Fun with fermentations: Black coffee in bed with help from microbes

Posted on February 2, 2019 by Douglas Powell

Australia is, for reasons I’ll never understand, a country of coffee snobs, with their baristas and their 20-minute preparation times and the $4.50 a cup.

No Tim Hortons here (sadly, the co-founder of the venerable Canadian chain passed away today).

According to research published February 1 in the journal, Applied and Environmental Microbiology, when processing coffee beans, longer fermentation times can result in better taste, contrary to conventional wisdom. Lactic acid bacteria play an important, positive role in this process. Other species of microbes may play a role in this process as well, but more research is needed to better understand their role.

“A cup of coffee is the final product of a complex chain of operations: farming, post-harvest processing, roasting, and brewing,” said principal investigator Luc De Vuyst, M.Sc., Ph.D., Professor of Industrial Microbiology and Food Biotechnology, Vrije Universiteit Brussel, Brussels, Belgium. “There are several variants of post-harvest processing, among which wet processing and dry processing are the most common.” Wet processing—commonly used for Arabica and specialty coffees—is the step that includes fermentation.

“We carried out the research at an experimental farm in Ecuador through a multiphasic approach, encompassing microbiological, metabolomics, and sensory analysis,” said Dr. De Vuyst.

Fermentation was of particular importance. During extended fermentation, leuconostocs—a genus of lactic acid bacteria used in the fermentation of cabbage to sauerkraut and in sourdough starters—declined in favor of lactobacilli, said Dr. De Vuyst. Lactic acid bacteria were already present before fermentation, and these acid tolerant lactobacilli proliferated even more during this process.

However, it is challenging to draw a causal link between the microbiota and the volatile compounds in the beans—those compounds that contribute to the coffee’s smell – since many of these compounds can be of microbial, endogenous bean metabolism, or chemical origin,” said Dr. De Vuyst.

“However, we did see an impact of the microbial communities, in particular the lactic acid bacteria,” said Dr. De Vuyst. They yielded fruity notes, and may have “had a protective effect toward coffee quality during fermentation because of their acidification of the fermenting mass, providing a stable microbial environment and hence preventing growth of undesirable microorganisms that often lead to off-flavors,” he said.
“Furthermore, there is a build-up of the fermentation-related metabolites onto the coffee beans, which affects the quality of the green coffee beans and hence the sensory quality of the coffees brewed therefrom,” said Dr. De Vuyst.

Dr. De Vuyst emphasized that how each stage of processing influences the taste of coffee remains mostly uncharted. “We were aware of many different microorganisms during wet coffee fermentation — enterobacteria, lactic acid bacteria, yeasts, acetic acid bacteria, bacilli, and filamentous fungi,” said Dr. De Vuyst, but it is still unknown how most bacteria influence this process.

The work was a collaboration between the Vrije Universiteit Brussel, and Nestlé Research. “Nestlé was interested in the fundamental aspects of coffee processing, in particular, the post-harvest processing chain, in order to correlate it with the roasting process and of course the final cup quality,” said Dr. De Vuyst.

Fermentations: A microbiological orgasm for food and drink

Posted on December 12, 2016 by Douglas Powell

Third-year university in 1983, and things started to click.

I was bored, angst-ridden and wondering what am I doing here.

home-made preserves for the winter isolated on white background

Then I took an industrial microbiology class.

Fermentations.

(And no, Michael Pollan didn’t invent bragging about fermentations either).

The next year I took a virology class and suddenly realized: we humans are hosts on a microbiological planet.

The way these bugs move genes around, invade others, and have been crucial to the evolution of humans has intrigued me ever since.

Kim Painter of USA Today writes that Americans used to find yogurt yucky. But the creamy dairy food long ago joined beer and cheese on the list of our favorite things produced by fermentation — an ancient preservation process in which bacteria transform food and drink, creating new flavors and, many consumers believe, enhanced health benefits.

So maybe it’s not surprising that thousands of people now show up at fermentation festivals around the country to make sauerkraut and sample kombucha teas, Korean kimchi and Japanese natto. The same folks flock to pop-up “kraut mobs” and study books such as Wild Fermentation and The Art of Fermentation, both by the movement’s guru, Sandor Katz.

“I would say that virtually every event I do these days is at capacity, and I’m not accepting every invitation. I can’t physically do it,” Katz says. He spoke from China, where he was on a quest for more fermentation wisdom.

Fermentation is the hottest trend in plant-based eating, according to recent survey of registered dietitians by The Monday Campaigns, a non-profit organization that promotes healthy lifestyles.

Jeremy Ogusky, a Boston pottery maker, sees it firsthand as founder of Boston Ferments, the host group for a summer festival that drew a few hundred people four years ago and 14,000 this year. “It’s just grown every year,” he says. “It’s kind of crazy.”

And what about safety, especially for foods fermented at home? After all, the process typically requires leaving jars of foodstuffs sitting out for weeks, without the final sanitizing steps used in standard canning. (Heat processing can be added for some foods, but purists generally frown on that.)

The history of fermentation, especially with vegetables, is mostly reassuring. When properly done, fermentation produces acids that kill most worrisome microorganisms, says my barfblog.com friend, who also shares a love of fermentations, Benjamin Chapman, an associate professor and food safety extension specialist at North Carolina State University.

“We have lots of data showing that if you get the correct pH drop, the correct acidity level, you can create a really, really low risk product,” he says. But he says risks are not zero, and some cases of home fermenters making mistakes and creating unsafe foods have been reported. That’s why he urges people to use only long-tested recipes and techniques.

From the duh files: Slow lorises and aye-aye lemurs prefer alcohol over water

Posted on July 21, 2016 by Douglas Powell

Biologists at Dartmouth College in New Hampshire discovered that when faced with the choice of various sugary substances laced with different alcohol concentrations, the loris and aye-ayes repeatedly chose the most alcoholic solution.

In fact the researchers report in the Royal Society Open Science, the aye-ayes loved the concoction so much they enthusiastically searched for more, while the slow loris displayed “a relative aversion to tap water”.

Interestingly, the alcohol did not seem to affect the creatures.

Samuel Gochman, a biology student at Dartmouth, said: “No signs of inebriation were observed,” reports The Guardian.

The aye-aye’s tolerance to alcohol may be explained by a genetic mutation, which speeds up the rate alcohol is broken down.

“The results indicate that the mutation might (have) a preference for alcohol,” Gochman said.

Massachusetts fermenter known for its unpasteurized tempeh wins award

Posted on January 20, 2016 by Ben Chapman

According to the Berkshire Eagle, lacto-fermented vegetables are all the rage. But I’d be concerned about how food safety is managed.

Hosta Hill, a Berkshires-based maker of lacto-fermented vegetables and unpasteurized tempeh, has been honored with a 2016 Good Food Award for its Gochu Curry Kraut, a variation on traditional sauerkraut featuring Indian and Korean influences.

“We’re thrilled to be recognized for the second consecutive year by the Good Food Awards,” Elling, a Berkshires native and graduate of Monument Mountain High School in Great Barrington, said in the press release announcing the award. “We love that they say we ‘celebrate the kind of food we all want to eat: tasty, authentic and responsibly produced’ because it acknowledges the complete method behind the meal. To have our handmade ferments, featuring sustainably grown ingredients from right here in the Berkshires, reach a national audience and be mentioned in the same sentence as so many of these other great companies is an incredible honor.”

Does responsibly produced include vetting their starter culture suppliers and asking them to test their products for Salmonella. And telling the folks who use the unpasteurized tempeh that they need to handle it like raw meat?

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