Charcuterie_ The Craft of Salting, Smoking, and Curing - Michael Ruhlman [82]
CURING SALTS (SODIUM NITRITE AND SODIUM NITRATE)
Some form of curing salt must be used in any dry-cured sausages. The warm, anaerobic, protein-rich interior of a sausage is an ideal environment for the bacteria that produce the potentially fatal nerve toxin causing botulism poisoning. Sodium nitrite, refered to in our recipes as pink salt (see Sources, page 301), prevents these bacteria from growing. Sodium nitrate, which is kind of a time-release form of sodium nitrite, must be used in all dry-cured sausages cured over longer periods. Always use the curing salts in the proportions indicated in the recipes here. Remember that they are dangerous if ingested accidentally, so use exactly as stated in the recipe and keep them out of the reach of children.
Nitrites are added to cures for either dry-curing or smoking, processes in which the meat is held at between 40 and 140 degrees F./4 and 60 degrees C., temperatures at which harmful bacteria multiply rapidly. Nitrites have three functions, one related to health, one to appearance, one to flavor: (1) Nitrites kill a range of bacteria, most notably the one responsible for botulism. (2) Nitrites help preserve the pink color that we associate with tasty meats and retard rancid flavors in the fat. A sausage or terrine cured with nitrite will retain a rosy interior hue, one without will turn gray, even when they both have reached an internal temperature of 150 degrees F./65 degrees C. (3) Nitrites add a piquant flavor to meats (a chicken cured with pink salt will have a distinct ham flavor and rosy hue).
Nitrates are also an essential curing agent, but nitrates do nothing beneficial to food until they convert to nitrite. Nitrates act like a time-release capsule for items requiring especially long cures (such as salami, which may be cold-smoked and then dried for weeks). Nitrates began to be added to cured and smoked meats as early as the 1500s in the form of saltpeter, potassium nitrate. The compound was used in America until the 1970s, when it was deemed too inconsistent to be safe (though it remains common in Europe). Sodium nitrate is now manufactured and sold under the names Insta Cure #2 and DQ Curing Salt #2 (see Sources, page 301).
How Real Is the Danger of Botulism?
If you get it, very; the toxin is considered to be one of the most poisonous substances on earth.
How likely are you to get it? Not very.
According to the Centers for Disease Control and Prevention, twenty-five or so people a year contract food-borne botulism in the United States, usually as a result of improper home canning. If botulism spores, which are hard to kill, get into a can or jar or are ground into the center of a sausage, then sealed in an oxygen-free, nonacidic environment, they thrive. Botulism has been caused here by canned tuna and garlic stored in olive oil. (In Japan, preserved fish is the chief culprit.)
There are three parts to the botulism equation: Botulism spores develop into the bacteria Clostridium botulinum, which in turn produces the deadly toxin. The spores, which are typically found in soil, are difficult to kill but aren’t harmful (except, potentially, to infants), and the bacteria themselves aren’t harmful either. But allow the bacteria to grow in an anaerobic nonacidic environment between 40 degrees F./4 degrees C. and 140 degrees F./60 degrees C., and they will start producing the deadly toxin.
NITRITES AND YOUR HEALTH: Nitrites remain controversial because they can produce, under certain circumstances, organic compounds called nitrosamines, some of which can cause cancer. Nitrites are found naturally in some vegetables that grow in the ground (add chopped spinach to a white sausage and you may see the meat begin to turn pink, as the nitrites in the spinach begin to cure the meat). We probably consume far fewer nitrites than our ancestors did (at least those who relied far more on preserved food). There is also growing evidence that vitamin C (ascorbic acid) enhances the effect of nitrites while prohibiting the development