Salt, as long as it is produced by a regular manufacturer and sold through legitimate channels, is generally safe for consumption. Different types of salt suit different individuals. Most people are suited to consuming regular iodized salt, while those with hyperthyroidism may benefit from iodine-free salt, and individuals with hypertension are advised to use low-sodium salt.
Salt can absorb moisture from the air, leading to clumping if left for extended periods. To prevent this, manufacturers add anticaking agents to salt. Common anticaking agents include potassium ferrocyanide, silica dioxide, calcium silicate, and ferric ammonium citrate, with potassium ferrocyanide being the most commonly used.
There was a period of public concern about anticaking agents in salt, particularly potassium ferrocyanide, due to its name containing “cyanide.” However, potassium ferrocyanide and cyanide are entirely different substances.
The safety of a substance is assessed using various criteria. Acute toxicity is measured by the lethal dose. The lethal dose of potassium ferrocyanide is between 1600 to 3200 milligrams per kilogram of body weight, while for salt, it’s around 3000 milligrams per kilogram of body weight. This means that a person weighing 60 kilograms would potentially die from consuming 180 grams of salt in a short period, a dose similar to potassium ferrocyanide.
Chronic toxicity is assessed using the acceptable daily intake. The acceptable daily intake for potassium ferrocyanide is 0.025 milligrams per kilogram of body weight. For a 60-kilogram adult, this would require consuming over 1.5 milligrams of potassium ferrocyanide daily to have a long-term effect. The standard for adding potassium ferrocyanide as an anticaking agent to salt is not to exceed 10 milligrams per kilogram of salt. Therefore, to consume 1.5 milligrams of potassium ferrocyanide, one would need to ingest 150 grams of salt in a day, a quantity unlikely for most people.
Potassium ferrocyanide, as a food additive, has undergone tests for teratogenicity and carcinogenicity to be legally permitted for use. It is recognized as a food additive globally, including in the European Union, the United States, Japan, and other major regions.
Another concern is whether potassium ferrocyanide can release cyanide. Under specific conditions, potassium ferrocyanide can decompose and release cyanide, requiring temperatures above 400 degrees Celsius. However, typical cooking temperatures rarely exceed 200 degrees Celsius, even in the case of dry cooking, reaching just over 300 degrees Celsius. Therefore, there is no need to worry about potassium ferrocyanide in salt releasing cyanide.
