Curing (food preservation)

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Sea salt being added to raw ham to make Prosciutto.

Bag of Prague powder #1, also known as "curing salt" or "pink salt." It's typically a combination of salt and sodium nitrite, with the pink color added to distinguish it from ordinary salt.

Curing refers to various food preservation and flavoring processes, especially of meat or fish, by the addition of a combination of salt, nitrates, nitrite[1] or sugar. Many curing processes also involve smoking, the process of flavoring, or cooking. The use of food dehydration was the earliest form of food curing.[1]
Contents
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1 History 2 Chemical actions

o o o o

2.1 Salt 2.2 Sugar 2.3 Nitrates and nitrites 2.4 Smoke

3 See also 4 Notes 5 References 6 External links

[edit]History
Food curing dates back to ancient times, both in the form of smoked meat and as salt-cured meat.[2] The Plains Indians used to hang their meat at the top of their teepees to increase the amount of smoke coming into contact with the food.[2] It was discovered in the 1800s that salt mixed with nitrates (saltpeter) would color meats red, rather than grey, and consumers at that time then strongly preferred the red-colored meat.[1]

[edit]Chemical [edit]Salt

actions

Table salt (sodium chloride) is the primary ingredient used in meat curing.[2] Removal of water and addition of salt to meat creates a solute-rich environment where osmotic pressuredraws water out of microorganisms, retarding their growth.[2][3] Doing this requires a concentration of salt of nearly 20%.[3] In addition, salt causes the soluble meat proteins to come to the surface of the meat particles within sausages. These proteins coagulate when the sausage is heated, helping to hold the sausage together. [4] Finally, salt slows the oxidation process, effectively preventing the meat from going rancid.[3]

[edit]Sugar
The sugar added to meat for the purpose of curing it comes in many forms, including honey, corn syrup solids, and maple syrup.[5]However, with the exception of bacon, it does not contribute much to the flavor,[6] but it does alleviate the harsh flavor of the salt.[2]Sugar also contributes to the growth of beneficial bacteria like Lactobacillus by feeding them.[7]

[edit]Nitrates

and nitrites

Nitrosyl-heme

Nitrates and nitrites not only help kill bacteria, but also produce a characteristic flavor and give meat a pink or red color.[8] Nitrate (NO3), generally supplied by sodium nitrite or potassium nitrate, is used as a source for nitrite (NO2). The nitrite further breaks down in the meat into nitric oxide (NO), which then binds to the iron atom in the center of myoglobin's heme group, reducing oxidation and causing a reddish-brown color (nitrosomyoglobin) when raw, and the characteristic cooked-ham pink color (nitrosohemochrome or nitrosylheme) when cooked. The addition of ascorbate to cured meat reduces formation of nitrosamines, but increases the nitrosylation of iron. The use of nitrates in food preservation is controversial. This is due to the potential for the formation of nitrosamines when the preserved food is cooked at high temperature.[8] The usage of either compound is therefore carefully regulated; for example, in the United States, the concentration of nitrates and nitrites is generally limited to 200 ppm or lower.[8] However, they are considered irreplaceable in the prevention of botulinum poisoning from consumption of cured dry sausages by preventing spore germination.[9] A 2007 study by Columbia University suggests a link between eating cured meats and chronic obstructive pulmonary disease. Nitriteswere posited as a possible cause.[10]

[edit]Smoke
Main article: Smoking (cooking) Meat can also be preserved by "smoking", which is to dry the meat in the presence of wood fire that produces large amounts of smoke. Drying meat while smoking it will also keep it tender.[11] One method of smoking calls for a smokehouse with damp wood chips orsawdust.[12] In North America, hardwoods such

as hickory, mesquite and maple are commonly used for smoking, as are fruit woods such as apple, cherry and plum, and even corncobs. Smoking originally kept flies from coming into contact with the meat, preventing the possibility of the laying of fly eggs and maggots until the meat was properly dried. The smoking can be done in combination with other curing methods such as salting, and helps seal the outer layer of the food being cured, making it more difficult for bacteria to enter. Slower and warmer smoking methods can be used to dehydrate the meat, further decreasing its susceptibility to bacteria, similar to jerky. There are several types of smoking styles, but hot smoking, smoke roasting (pit barbecuing) and cold smoking are the most common. Smoke roasting and hot smoking actually cooks the food while cold smoking does not and is the oldest form of smoking meat for preservation, as the food is only exposed to the cooler smoke of the wood before it exits the smoking device.

http://en.wikipedia.org/wiki/Curing_(food_preservation)

Nearly all proteins and vegetables (and even fruits!) can be preserved or cured with salt for different reasons and with different outcomes. Pork, bacon, and duck are often preserved with dry saltmeaning a salt rub is thoroughly applied and the proteins are left to cure (and essentially dry out) anywhere from a day or two to several weeksdepending on your intent. Or the food could be preserved and cured in brine, which is essentially a salty, watery mixture that will have a pickling effectespecially with your vegetables.

http://www.beyondtheshaker.com/pages/Salt-Guide-Page-Four.html

Nitrates and nitrites have gotten a pretty bad rap in the past few years. Present in such modern picnic food as cold cuts and hot dogs, but used as a traditional meat-curing ingredient since the 16th century, studies have more recently labeled nitrites as possible carcinogens.

With Grill Month in full swing, we thought we'd take a moment to give you the scoop on what exactly nitrates are and what they've been doing in our food all these years. Read on! Nitrates are a naturally occurring form of potassium first discovered during the Middle Ages and given the name 'saltpeter.' When used for curing, nitrates react with the meat tissues to form nitrites. These days, saltpeter is often replaced with a small amount of pure nitrite. Nitrites play a key chemical and cosmetic roles in curing and processing meats:

They slow or stop the growth of bacteria as the meat is curing, specifically botulism. They keep the fat within the meat fresh and prevent it from going rancid. They contribute a sharp, "cured" flavor that we've come to like and associate with cured meats. They give cured meats their characteristic rosy-red color.

Whether or not nitrites cause cancer is still widely debated, with some studiesconfirming carcinogenic effects and other studies proclaiming the health-benefits of nitrites! Good or bad, the amount of nitrites in our food has steadily decreased over the past several decades. Today, residual nitrates and nitrites in cured meat must be less than 200 parts per million (0.0002%) in the United States. Like most things we eat, we have a feeling it's all about moderation and being sensible. What do you think?
http://www.thekitchn.com/the-good-bad-and-ugly-nitrites-55456