Rising price for organic agent? (6)

I believe the answer is:

rennet

I'm a little stuck... Click here to teach me more about this clue!

'agent?' is the definition.
(I have seen 'Curdling agent ' mean 'rennet' so perhaps 'agent' could also mean 'rennet')

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for rennet that I've seen before include "Cheese curdling agent" , "Agent for cheesemaker" , "Causing vomiting" , "cheese maker?" , ""This has turned the milk!"" .)

I've seen this clue in The Telegraph.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.