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NYT Syndicate
When you slice into a salami, you are enjoying the fruits of some very small organisms' labour.
Like other dried sausages, salami is a fermented food. Its production involves a period where manufacturers allow microbes to work on the ground meat filling to create a bouquet of pungent, savory molecules. Traditionally, the bugs find their way to the sausage from the surrounding environment. But these days, industrial manufacturers add a starter culture of bacteria to the meat instead, much the way a bread baker adds a packet of yeast to her dough.
It's safer this way, and leads to more consistent results. These industrial starters may not always yield the most inspired flavour, though.
A recent study from researchers at the University of Turin, published in the journal Applied Environmental Microbiology, found that salami made with wild bugs scored higher with tasters than salami made with a starter culture. The amount of acid produced by the industrial bacteria as it works over the meat might explain the difference.
At the beginning of the experiment, Luca Cocolin, a professor of microbiology at University of Turin, and his colleagues had a local salami manufacturer create two batches, using, lard, pepper, coriander, nutmeg and other ingredients according to their usual recipe. A starter was added to one batch and not to the other, and after the filling was packed into sausage casings and hung up to ferment, the researchers checked in on the microbes three, seven and 40 days later.
What they saw was an explosive growth in the starter bacteria, to the exclusion of almost any other type. Very soon, they began to produce molecules that are usually made later on in the fermentation process, suggesting that having little competition had perhaps allowed them to jump the gun. In contrast, a rainbow of species cropped up more gradually in the other salami, generating a correspondingly more complex ” and apparently more pleasant ” array of scent and flavour molecules.
Even worse, the microbes in the industrial starter were pumping out acetic acid, the key ingredient in vinegar. That's not a flavour Italian salami aficionados look for.
"If you have these notes that are strong in your product," Cocolin said,"it's not good."
This doesn't mean that the starter culture needs to be totally revamped, he said. A small change in the procedure may be enough to get better results: In these salami, the dominance of the starter bacteria and their tendency to produce acid could perhaps have been controlled by lowering the temperature, he suggests. If they were kept in a space that was a little cooler, the bacteria would grow more slowly, perhaps allowing a few other species to find a niche in the sausage and toning down the breakneck pace of acid production.
Still, the idea of a more tailored approach ” perhaps using microbes captured from the wild to get a better flavour ” is tantalising. In fact, identifying bacteria for a starter for artisanal Piedmontese salami will be part of the researchers' next project.
