Subject: Growing bacteria

I am doing a science fair project.  I want to test the effect of household 
products on common kitchen germs.  Does 409 , Lysol,etc. really kill germs.  
I have blood agar in petri dishes. I want to swab some germs from off the 
counter and then clean the area with a product and swab the area again to see 
if there is a difference in the amount of bacterial growth. Will this work?  
Or should  I Culture the bacteria and after the growth occurs then add the 
products to the petri dish to see if the growth dies?  I've had a hard time 
finding a book to help me.  Thank you for your help! 

Re: Growing bacteria