Question: How do people often cure sausages?
About the article "Sausage", section "China".

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Fresh sausages are simply seasoned ground meats that are cooked before serving.
Fresh sausages normally do not use cure (Prague powder #1) although cure can be used if desired.
In addition fresh sausages typically do not use smoke flavors, although liquid smoke can be used.
Fresh sausages are never smoked in a cold smoker because of the danger of botulism.
The primary seasoning agents in fresh sausages are salt and sugar along with various savory herbs and spices, and often vegetables, including onion and garlic.
A British Fresh sausage typically contains around 10% butcher's rusk, 10% water, 2.5% seasoning, and 77.5% meat.
At point of sale British sausages will often be labelled as "actual meat content X%".
As meat can be fatty or lean, the X% is calculated using reference tables with the intention to give a fairer representation of the "visual lean" meat content. 
A European-like-style smoked savory "hóng cháng" (红肠 "red sausage") is produced in Harbin, China's northernmost major city.
It is another notable product similar to Lithuanian and Polish sausages including kiełbasa and "podhalańska", in that they tend to be of a much more European flavours than other Chinese sausages.
This kind of sausage was first produced in a Russian-capitalized factory named Churin sausage factory in 1909, Since then Harbin style sausage become popular in China, especially in northern regions.
Lap cheong (also lap chong, lap chung, lop chong) are dried pork sausages that look and feel like pepperoni, but are much sweeter.
In southwestern China, sausages are flavored with salt, red pepper and wild pepper.
People often cure sausages by smoking and air drying.
Nordic sausages (, , , ) are usually made of 60–80% very finely ground pork, very sparsely spiced with pepper, nutmeg, allspice or similar sweet spices (ground mustard seed, onion and sugar may also be added).
Water, lard, rind, potato starch flour and soy or milk protein are often added for binding and filling.
In southern Norway, grill and wiener sausages are often wrapped in a potato lompe, a kind of lefse.
Virtually all sausages will be industrially precooked and either fried or warmed in hot water by the consumer or at the hot dog stand.
Since hot dog stands are ubiquitous in Denmark (known as "Pølsevogn") some people regard "pølser" as one of the national dishes, perhaps along with medisterpølse, a fried, finely ground pork and bacon sausage.
The most noticeable aspect of Danish boiled sausages (never the fried ones) is that the cover often contains a traditional bright-red dye.
They are also called "wienerpølser" and legend has it they originate from Vienna where it was once ordered that day-old sausages be dyed as a means of warning.
The Swedish "falukorv" is a similarly red-dyed sausage, but about 5 cm thick, usually baked in the oven coated in mustard or cut in slices and fried.
Unlike ordinary sausages it is a typical home dish, not sold at hot dog stands.
Other Swedish sausages include "prinskorv", "fläskkorv", "" and "isterband"; all of these, in addition to "falukorv", are often accompanied by potato mash or "rotmos" (a root vegetable mash) rather than bread.
In Iceland, lamb may be added to sausages, giving them a distinct taste.
Horse sausage and mutton sausage are also traditional foods in Iceland, although their popularity is waning.
Liver sausage, which has been compared to haggis, and blood sausage are also a common foodstuff in Iceland. 
Making dry sausages involves curing salts, which incorporate sodium nitrite and sodium nitrate.
Nitrites are used for all types of sausages and are the most common.
Nitrates are used only in the preparation of the cured dry style of sausages.
Over a period of time the nitrates are converted into nitrites by endogenous or added bacteria.
The human digestive system manufactures nitrites, which is thought to be what prevents botulism, which would thrive in the anaerobic conditions and temperature range of the digestive system (gut).
Cured meat products typically contain less than 40 ppm "w"/"w" nitrites.
Potassium nitrite and potassium nitrate additions allow the production of sausages with lower levels of sodium.
When using the potassium form, it is necessary to include other ingredients to mask the bitter flavours it imparts.
Old recipes use saltpetre which is not recommended.
The primary reason is that often these old recipes contain many times more curing ingredients than are appropriate.
Modern techniques are readily available and do a much better job.
In the sausage industry the nitrites and nitrates are pre-formulated into products called Prague powder#1 and Prague powder#2.
Prague powder #1 contains 6.25% sodium nitrite and 93.75% sodium chloride and is used for the preparation of all cured meats and sausages other than the dry type.
Prague powder #2 contains 1 ounce of sodium nitrite (6.25%) and 0.64 ounces sodium nitrate (4.0%) per pound of finished product (the remaining 14.36 ounces is sodium chloride) and is used for the preparation of cured dry sausages.
Prague powder #2 should never be used on any product that will be fried at high temperature (e.g.
bacon) because of the resulting formation of nitrosamines.
When using cure, it is very important to never exceed the recommended amount of 4 ounces of Prague powder #1 in 100 pounds of meat (2.5 g/kg).
Equivalently this is 2 teaspoons for 10 pounds.
Note that the maximum allowable amount of sodium nitrite and potassium nitrite is governed by regulations and is limited to 0.25 ounces per 100 pounds of chopped meat.
Since Prague powder #1 is a 1:15 dilution (in a pound of Prague powder #1 one ounce is sodium nitrite and 15 ounces are common table salt), we get the proper amount at a rate of 4 ounces added to of meat.
Sodium nitrate and potassium nitrate are limited to 2.75 ounces per 100 pounds.
Sodium and potassium nitrite are quite toxic to humans with the lethal dose being about 4 grams.
As little as 22 mg/kg of body weight can cause death.
This is about 2.2 grams for a body mass of 100 kg.
Thus, there is enough sodium nitrite in 2 ounces of Prague powder #1 to kill a person.
Morton's Tenderquick is the brand name of another formulation of sodium nitrite, with salt and sugars added.
It is not the same concentration as either "Prague powder #1 or #2".
Since the amount of nitrite present in a recipe is essential for safety, one cannot take a recipe designed for Prague powder and simply substitute like amounts of such products as Morton's Tenderquick.
To do so would invite the risk of botulism poisoning.
Similarly, one cannot just substitute Prague powder #1 in place of Morton's Tenderquick.
For any such substitutions, one must calculate the exact amount of nitrite required and make the proper adjustments. 
One of the most common reasons for fires is how people often leave stoves, ovens, toasters, clothing irons, barbecues, and candles unattended.