Garbage pickup was running 7 days a week.Next, every surface needs to be cleaned with soap and water and then bleach. 

Will try the bleach and acid solutions.

bleach will kill. 

Make sure tenants understand that  you don't do 7 loads of laundry back to back or pour chemicals (including bleach) down the drains, etc.

Use TSP and Bleach in a bucket of hot water.  

Enzymes work very well and leave no unpleasant odor but they're very expensive so I would probably opt for the bleach technique first on your concrete floor.

The unit was vacant, and obviously you didn't do any preventative maintenance, bleach down the drain line, which needs to be done occasionally.

I taped some instructions to the air handler about changing the filter and putting bleach down the condensate tube to prevent backups.

We bleached the floor and paint the walls and floor with one coat of original kilz, then added regular paint and new carpet and it was perfect.  

@Nickey Ramsey   Mold and foreclosures go together.. all most all vacant type homes will have some sort of mold.. its totally over blown.. you simply grab your sprayer and bleach and go at it.I have never hired a MOLD specialist  waste of money in my mind... just kill the stuff and move on.