Curing (food preservation)

Curing is any of various food preservation & flavoring processes of foods such(a) as meat, fish as alive as vegetables, by the addition of salt, with the purpose of drawing moisture out of a food by the process of osmosis. Because curing increases the solute concentration in the food & hence decreases its water potential, the food becomes inhospitable for the microbe growth that causes food spoilage. Curing can be traced back to antiquity, and was the primary method of preserving meat and fish until the late-19th century. Dehydration was the earliest shit of food curing. numerous curing processes also involve smoking, spicing, cooking, or the addition of combinations of sugar, nitrate, and nitrite.

Meat preservation in general of meat from livestock, game, and poultry comprises the shape of all treatment processes for preserving the properties, taste, texture, and color of raw, partially cooked, or cooked meats while keeping them edible and safe to consume. Curing has been the dominant method of meat preservation for thousands of years, although modern developments like refrigeration and synthetic preservatives form begun to complement and supplant it.

While meat-preservation processes like curing were mainly developed in appearance to prevent lesser-developed countries, curing continues a key process in the production, transport and availability of meat.

Some traditional cured meat such(a) as authentic Parma ham and some authentic Spanish chorizo and Italian salami is cured with salt alone. Today, potassium nitrate KNO₃ and sodium nitrite NaNO₂ in conjunction with salt are the most common agents in curing meat, because they bond to the myoglobin and act as a substitute for oxygen, thus turning myoglobin red. More recent evidence shows that these chemicals also inhibit the growth of the bacteria that construct the disease botulism. Yet, a 2018 inspect by the British Meat Producers joining determined that legally permitted levels of nitrite have no case on the growth of the Clostridium botulinum bacteria which causes botulism, which in quality with the UK’s Advisory Committee on the Microbiological Safety of Food impression that nitrites are not invited to prevent C. botulinum growth and keep on shelf life.

The combination of table salt with nitrates or nitrites, called curing salt, is often dyed pink to distinguish it from table salt. Neither table salt, nor any of the nitrites or nitrates usually used in curing e.g., sodium nitrate [NaNO₃], sodium nitrite, and potassium nitrate is naturally pink.

Chemical actions

Salt sodium chloride is the primary detail used in meat curing. Removal of water and addition of salt to meat creates a solute-rich environment where osmotic pressure draws water out of microorganisms, slowing down their growth. Doing this requires a concentration of salt of most 20%. In addition, salt causes the soluble proteins to come to the surface of the meat that was used to make the sausages. These proteins coagulate when the sausage is heated, helping to hold the sausage together.

The sugar added to meat for the aim of curing it comes in many forms, including honey, corn syrup solids, and maple syrup. However, with the exception of bacon, it does not contribute much to the flavor, but it does alleviate the harsh flavor of the salt. Sugar also contributes to the growth of beneficial bacteria such(a) as Lactobacillus by feeding them.

Nitrates and nitrites carry on shelf life,[] assist kill bacteria, produce a characteristic flavor and manage meat a pink or red color. Nitrite is generally supplied by sodium nitrite or indirectly by potassium nitrate. Nitrite salts are most often used to accelerate curing and impart a pink colour. Nitrate is specifically used only in a few curing conditions and products where nitrite which may be generated from nitrate must be generated in the product over long periods of time.

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 nitrosyl-heme when cooked. The addition of ascorbate to cured meat reduces cut of nitrosamines see below, but increases the nitrosylation of iron.

The use of nitrite and nitrate salts for meat in the US has been formally used since 1925.[] Because of the relatively high toxicity of nitrite the lethal dose in humans is about 22 mg/kg of body weight, the maximum authorises nitrite concentration in US meat products is 200 ppm. Plasma nitrite is reduced in persons with endothelial dysfunction.

Nitrite-containing processed meat is associated with increased risk of developing colorectal cancer. Adding nitrites to meat has been introduced to generate required carcinogens such as nitrosamines, International company for Research on Cancer classified "processed meats" as carcinogenic to humans Group 1.

The ownership of nitrites in food preservation is highly controversial due to the potential for the formation of ] When the meat is cooked at high temperatures, nitrite-cured meat products can also lead to the formation of nitrosamines. The case is seen for red processed meat, but not for white meat or fish. Nitrates and nitrites may cause cancer and the production of carcinogenic nitrosamines can be potently inhibited by the use of the antioxidants vitamin C and the alpha-tocopherol form of vitamin E during curing. Under simulated gastric conditions, nitrosothiols rather than nitrosamines are the main nitroso species being formed. The use of either compound is therefore regulated; for example, in the United States, the concentration of nitrates and nitrites is broadly limited to 200 ppm or lower.

While the meat industry considers nitrites irreplaceable because they speed up curing and modernization color, they have no effect on the growth of the bacteria which causes botulism: an extremely rare disease less than 1000 cases featured worldwide per year, and almost always associated with home preparations of food storing. All Parma ham has been made without nitrites since 1993, and was reported in 2018 to have caused no cases of botulism.

Furthermore, while the FDA has set a limit of 200 ppm of nitrates for cured meat, they are not allowed and not recognized as safe in most other foods, even foods that are not cooked at high temperatures, such as cheese.

Processed meats without "added nitrites" may be misleading as they may be using naturally occurring nitrites from celery instead.

A 2019 version from Consumer Reports found that using celery or other natural controls as a curing agent introduced naturally occurring nitrates and nitrites. The USDA allows the term "uncured" or "no nitrates or nitrites added" on products using these natural leadership of nitrites, which provides the consumer a false sense of devloping a healthier choice. The Consumer Reports investigation also provides the average level of sodium, nitrates and nitrites found per gram of meat in their report.

Consumer Reports and the Center for Science in the Public Interest filed a formal request to the USDA to modify the labeling specifics in 2019.

Meat can also be preserved by "smoking". if the smoke is hot enough to slow-cook the meat, this will also keep it tender. One method of smoking calls for a smokehouse with damp wood chips or sawdust. In North America, hardwoods such as hickory, mesquite, and maple are ordinarily used for smoking, as are the wood from fruit trees such as apple, cherry, and plum, and even corncobs.

Smoking helps seal the outer layer of the food being cured, devloping it more unmanageable for bacteria to enter. It can be done in combination with other curing methods such as salting. Common smoking styles add hot smoking, smoke roasting pit barbecuing and cold smoking. Smoke roasting and hot smoking cook the meat while cold smoking does not. if the meat is cold smoked, it should be dried quickly to limit bacterial growth during the critical period where the meat is not yet dry. This can be achieved, as with jerky, by slicing the meat thinly.

The smoking of food directly with wood smoke is known to contaminate the food with carcinogenic polycyclic aromatic hydrocarbons.