I would test the urine before applying it to the char.
I would recommend creating a lot system for the urine collection for the purpose of traceability. The volume of the lot is based on risk management and not on science. It is a business decision.
Each lot should be tested and the lot test data provided to the grower.
The pathogens we test for include generic Ecoli, Salmonella, fecal coliform, and shigella toxin. Here in the US these test take around 5 days to get done and cost around $100 total.
You may want to consider a "kill" step using either dropping the pH or adding an essential oil. The kill step provides assurance that no matter what happens upstream, the material applied to the crop is pathogen free at the time of delivery.
In addition, are you familiar with HACCP....? Hazard Analysis Crtical Control Points is a food safety approach that maps all of the steps in a process where a contaminant, physical, biological, chemical, can enter the process.
Food Safety is all about risk management. Lot control is all about limiting the size of your risk.
my 3 cents
Mike, a Food Safety/ HACCP auditor in a prior life.......