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How Scientists Are Building a Better Sausage with Baby Poop

A group of Spanish researchers recently won an award for their brave foray into dirty diapers, where they sourced colonies of potentially health-boosting bacteria. And what's one to do with a clutch of gut bugs but stuff them into sausage?
Photo via Flickr user Tim Ertl

There's a lot of truth in that old adage—often but errantly attributed to Otto von Bismarck—about people not wanting to see how the sausage gets made.

And that sausage isn't even made with baby shit.

But perhaps sausage can be made even better with baby shit, or at least the beneficial bacteria that happily lives inside it. For their research on just this topic, a group of Spanish scientists recently won an Ig Nobel prize, an honor bestowed upon some of the most outré advancements in the scientific community, from the effects of opera on mice who've received heart transplants to the treatment of asthma with roller-coaster rides.


This group of researchers, however, was interested in developing a new kind of functional food—a living sausage teeming with immune-boosting probiotic bacteria. Baby shit was merely the method to get there.

Let's back up a sec: Probiotics are already commonplace in supermarkets and pharmacies, but they tend to live within some kind of dairy-based carrier, such as yogurt or kefir. The researchers wanted to expand to other fermented foods. Heck, why not sausage?

In addition to its putative health benefits, bacteria is also important in giving the sausage its signature tang and texture. "Lactobacillus are the main [bacteria] responsible for the fermentation of the meat mixture," study author Margarita Garriga told MUNCHIES. "They metabolize the carbohydrates added to the meat mixture to [produce] lactic acid." That acid adds a slightly sour note, allows the meat to cohere, and makes the sausage shelf-stable, without refrigeration.

In order to make its way to your gut, the probiotic bacteria—in this case, several strains of Lactobacillus—must be able to survive a necessary dip in stomach acid, bile, and digestive enzymes. While previous studies have confirmed that strains of Lactobacillus sourced from Italian sausages could live through our rollicking gastrointestinal gauntlet, the researchers realized that they could also use bacteria that had previously made the trip—veteran bugs, if you will.


So they used poop.

Well, the bacteria living within poop, that is. The BMs in question came from 43 healthy babies "directly from the nappies," according to the study. The samples were then diluted in saline, plated on petri dishes, and grown into individual strains of lactic acid bacteria. The researchers then made a standard pork sausage with 20 percent fat—roughly the same content as a commercially prepared sausage—and added glucose, black pepper, and sodium ascorbate, which is used as a pH regulator. Finally, they inoculated the meat mixture with six different poop-sourced bacterial cultures in six different batches.

It's important to know that this isn't even the first time scientists have employed bacteria sourced from feces to make sausages: A 2008 study used both human and pig poop to make Iberian dry fermented sausages. The authors of that study concluded that the probiotics survived the sausage-making process "without any flavour deviation compared to sausage fermented by a commercial meat starter culture." You'd never know that parts of it came from the ass-end of pig. (And, considering that natural sausage casings are made from animal intestines, the microscopic progeny of pig shit bacteria should be the least of your worries.)

The results in the Spanish study were mostly positive, too, with two of the six strains successfully kicking off fermentation and dominating the other naturally present bacteria in the sausage. That's important because another potential use of certain Lactobacillus strains is controlling spoilage and food-borne pathogens—that is, they could be used as preservatives. Another strain was effective against Listeria and salmonella.

Don't expect baby-tainted sausage on store shelves anytime soon—the poop was just one road to the probiotic party town, and science has to start somewhere. Still, we had to ask Garriga how the sausage tasted. "Fine!" she said, adding that the researchers' "expert panel" couldn't tell the difference between the baby-made sausage and a conventional one.

Sounds like it's the shit.