E-251, also known as sodium nitrite, is a food additive commonly used as a preservative and color fixative in processed meats. It helps prevent the growth of harmful bacteria, particularly Clostridium botulinum, which can cause botulism. E-251 also contributes to the characteristic pink color of cured meats, such as bacon and ham. In addition to its use in food, E-251 has applications in the chemical industry, where it serves as a reagent in various chemical reactions. While it is generally recognized as safe when used in appropriate amounts, excessive consumption can lead to health concerns, including methemoglobinemia, a condition that affects the blood's ability to carry oxygen.