Dear+Failure.

__Chill__
 * You should never leave meat out to thaw on the counter.
 * Never leave meat out for that long period of time
 * Don't use a dirty grill.

Sincerely, Failure

Clean
 * You should've cleaned the vegetables before cutting them.
 * You also should've not left them on the counter.
 * Also you should've waited to put the salad dressing in for last.

Seperate
 * First of all you should have used 2 different plates for the hamburger meat.
 * Also you should have washed the cutting board after cutting the meat.
 * Then before cutting the vegetables washed the cutting board again.