You decide to sample the bacteria growing on several items in a laboratory space. You follow aseptic techniques and use applicator swabs dipped in a sterile broth solution to sample from the floor, the sink, and your shoe. You spread each sample on separate labeled agar plates for incubation. a. You want to be sure that the sterile solution you used for sampling was not contaminated. How would you set up a negative control to test this?

b. What result for your negative control would indicate that something is contaminated?