Instructions: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Input: What keeps people from getting sick?, Context: In more recent applications, hydrogen is used pure or mixed with nitrogen (sometimes called forming gas) as a tracer gas for minute leak detection. Applications can be found in the automotive, chemical, power generation, aerospace, and telecommunications industries. Hydrogen is an authorized food additive (E 949) that allows food package leak testing among other anti-oxidizing properties.
Output:
E 949