Read this passage from When Birds Get Flu and Cows Go Mad! by John DiConsiglio. E. coli 0157:H7 is generally spread from undercooked meat. But you can also get it from drinking raw milk, unpasteurized apple juice, or unchlorinated water. And—very rarely—it can appear in fresh, leafy vegetables that have been exposed to water contaminated by manure. Here’s how you can protect yourself from it.

Which best explains the purpose of the last line of the passage?

to conclude the section above
to signal the reader that steps will follow
to summarize the information that follows
to categorize the data in the paragraph above