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The Tastiest Sausages Bring Their Own Microbes to the Party

Scientists in Italy have crafted a recipe for tastier sausage — and the secret ingredient is the microbes found in meat, according to a new study.

Many types of sausages are made with the aid of bacterial fermentation, a process in which microbes convert the sugars in food into other compounds such as acids, gases and alcohols, giving the meat its unique flavor.

In the new study, researchers found that using bacteria naturally found in sausage — a process known as spontaneous fermentation — rather than adding commercially available bacteria to the meat can greatly improve the taste and smell of sausage and other processed meats. [Poop Sausage & Pee Drinks: 7 Gross 'Human' Foods]

Fermented sausages are made from mixtures of ground meat, salt, sugar, spices and curing agents. Generally, this type of sausage is fermented using either bacteria naturally found in the raw meat or by adding commercial "starter cultures" to the meat during manufacturing. The lactic acid produced by the fermenting bacteria, along with properly drying the meat, prevents it from spoiling.

Usually, "good" microbes that are naturally found in sausage meat start the spontaneous fermentation process, senior author Luca Cocolin, a professor of food microbiology, agricultural microbiology and food technology at the University of Turin in Italy, said in a statement. However, "it is hard to control spontaneous fermentation, because even if the conditions for their development are correct, the bacteria don't always initiate the process."

During either fermentation process, manufacturers also have to ensure the product's safety, Cocolin added. This is why starter cultures are commonly used, because they make the process easier, he said.

In the study, the researchers used gene-sequencing techniques to examine the microorganisms and map the metabolic pathways in both spontaneous fermentation and starter culture fermentation.  

This sequencing "makes it possible to determine which microbes are present in complex ecosystems, and what they are doing," Cocolin said in the statement.

The main specimen in the study was a type of Felino cured sausage manufactured in a local meat factory in Italy. They analyzed two batches of the same meat product — one made with a commercial starter culture of Lactobacillus sakei and Staphylococcus xylosus bacteria, and one made with spontaneous fermentation — to see the microbial makeup of the final products.

Additionally, the researchers also studied the biochemical reactions that took place during each fermentation process. Using a technique called gas chromatography with mass spectrometry, which assesses the different masses in a given sample, the researchers where able to determine what metabolites were produced during fermentation. (Metabolites are molecules produced by metabolism.)

Perhaps most important, the researchers found that the sausages made with a commercial starter culture had a higher acidity level and "inferior taste," compared with those made using spontaneous fermentation, the researchers said in the statement.

"The over-activity of the starter culture-inoculated sausages resulted in increased acetic acid and short-chain fatty acids," Cocolin said, describing the final sausage product as "pungent, vinegar, cheesy and weedy," according to the statement.

Fast-acting starter cultures are generally used at higher temperatures, which create a flavor that is that typically more sour and tangy.

The spontaneously fermented sausages, however, contained a different combination of compounds, including higher amounts "of medium- and long-chain fatty esters [that] enhanced the sensory profile of these sausages," said lead study author Ilario Ferrocino, a postdoctoral researcher in Cocolin's lab. Ferrocino described the sausages made using spontaneous fermentation as having a "fruity wine, waxy sweet apricot, and banana brandy" flavor, according to the statement.

Cocolin is no stranger to sausage production. His "laboratory has been involved in meat fermentation since the '90s, and considering the importance of the fermented sausage in Italy, at gastronomic, traditional and economic levels, we wanted to investigate better the role of spontaneous [microbes] and inoculated starters in the fermentation process," Cocolin said. "A deeper knowledge of the fermentation process allows the food producers to control better the microbiota, generating final products with high quality and safety."

Their findings were published today (Dec. 1) in the journal Applied and Environmental Microbiology.

Originally published on Live Science.