I remember my home ec teacher, as well as my mom, driving home the point of well-cooked meat. So much so, that today, I have trouble looking at a rare hamburger or steak. Then, I started reading about traditional foods and how some cultures actually eat raw meat. If this topic has your head spinning, too, keep reading. Ashley will answer the question, “Is raw fermented meat safe to eat?”
“The start of fermentation is nothing else but a war declaration by all bacteria residing inside the meat, and the stuffed sausage becomes the battlefront. (1)” Our ancestors have helped beneficial bacteria gain the upper hand to produce safe raw fermented meat for generations. What’s the secret? Water and acid.
Water
Though it seems hard to believe, salting meat as part of the fermentation process works to preserve foods in much the same way that freezing does. Harmful spoilage bacteria such as E.coli, Botulism, Listeria, and Salmonella have certain requirements for life, and all require the availability of water for survival. The availability of water, however, is not the same thing as the presence of water.
When you freeze meat or salt cabbage for kimchi, you are not removing water. True, salt does cause cabbage cells to break and release water, but the water remains in the fermentation vesicle, still present in vast quantity for spoilage. Rather than removing water, salt and freezing work to change the “water activity” in a food, or the available water to be used by bacteria for spoilage.
Water activity is the scientific way of denoting how tightly water is bound inside a food product, and how much water is available to be used by micro-organisms for either spoilage or fermentation. Adding salt, or freezing foods binds the water and reduces the amount of available water.
Though you don’t often think of it, freezing food causes the water in a food to turn into ice crystals, effectively binding them and preventing that water from being used by bacteria to spoil the food.
Water activity is measured on a scale of 0 to 1, with 0 being completely dry and 1 being pure water. Freshly ground meat to be used in fermented sausages has a water activity of 0.99, which is a perfect breeding ground for just about any sort of unpleasant bacteria to reproduce. Adding salt immediately reduces the water activity of ground meat, and for fermented sausage, the salt can reduce the water activity to around 0.96 instantly. This may not seem like a lot, but in the world of bacteria, a little change in water activity goes a long way.
Almost all pathogenic bacteria cannot survive at a water activity level less than 0.91, so that initial addition of salt is only the start to creating unfavorable conditions. The next step is acid.
Acid
The initial addition of salt retards but does not stop the growth of pathogenic bacteria. Beneficial lactic fermentation bacteria can thrive at a much lower water activity than harmful pathogenic bacteria, and once the salt has been added it’s time for them to go to work to win the war.
Lactic acid producing bacteria such as Lactobacillus and Pediococcus can live and reproduce in conditions that are between seven and 13 percent salt, depending on the strain. Fermented foods are generally started with three percent salt, both for palatability and to ensure the optimum growth of the lactobacillus while retarding the growth of other bacteria.
Since these lactic acid bacteria actually produce acid, their tolerance for acidified foods is much higher than less desirable bacteria. After being given a leg up with the initial salting, these lactic acid bacteria metabolize sugars and produce acid, creating a sour tangy flavor that gives lactic acid fermented foods some of there characteristic zing. Once a pH of five is reached, pathogenic bacteria can no longer reproduce and the lactic acid bacteria have won the war.
To be extra careful, some fermented sausage makers add both powdered lactic acid and starter cultures of lactic acid producing bacteria to ensure that the meat is properly acidified and safe for consumption. Historically, however, fermented sausage producers relied on technique and an ambient atmosphere of beneficial bacteria present in centuries-old curing rooms.
Water and acid are also the key to non-meat ferments in exactly the same way. Salt is added to lower the water activity of sauerkraut so that the naturally present Lactobacillus can do their work to acidify the cabbage to turn it into a tasty fermented food. Starter cultures, or a bit of the liquid from the last batch, can be added as an insurance policy and should be added if you intend to use less than the recommended amount of salt.
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One key to a successful ferment is the salt. The Himalayan powder salt that Fermentools sells is made to dissolve quickly in cool water. It also has more than 80 trace minerals. Save time and up the nutrition of your ferments with Himalayan powder salt. You can find it in the Fermentools store.
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(1) Marianski, Stanley, and Adam Mariański. The Art of Making Fermented Sausages. Seminole, FL: Bookmagic, 2009. Print.