硝酸カリウム

Origin

Potassium nitrate, also known as saltpeter or nitrate of potash, is a naturally occurring mineral. It can be found in various mineral deposits and is also produced synthetically. Historically, it was obtained from natural sources such as cave deposits and areas with decaying organic matter. Modern production methods involve reacting potassium chloride with sodium nitrate.

Usage

E252, potassium nitrate, is primarily used as a preservative in cured meats. It inhibits the growth of bacteria, particularly *Clostridium botulinum*, which causes botulism. It also contributes to the characteristic color and flavor of cured meats like ham, bacon, and salami. The nitrate is converted to nitrite, which then reacts with myoglobin to form nitrosomyoglobin, the pigment responsible for the pink color. Beyond food, potassium nitrate is used in fertilizers, fireworks, and gunpowder.

Side Effects

Potassium nitrate is generally considered safe at the levels used in food. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established an Acceptable Daily Intake (ADI) of 0-3.7 mg/kg body weight for nitrate ions from all sources, including potassium nitrate. Excessive intake of nitrates can lead to methemoglobinemia, particularly in infants, where hemoglobin is oxidized and unable to carry oxygen effectively. There is also concern about the formation of nitrosamines, which are carcinogenic compounds, when nitrates or nitrites react with amines in the stomach. However, the presence of vitamin C and other antioxidants can inhibit nitrosamine formation. Regulatory limits are in place to control the levels of nitrates and nitrites in food to minimize these risks.

Regulatory Status

Potassium nitrate (E252) is approved for use as a food additive in many countries, including the European Union and the United States. Regulations specify the maximum permitted levels in various food products. In the EU, it is subject to specific purity criteria and usage limits as outlined in Commission Regulation (EU) No 231/2012. In the United States, it is Generally Recognized As Safe (GRAS) when used in accordance with good manufacturing practices.