A 5 On Your Side consumer investigation of some hand sanitizers found some do not kill bacteria.

Consumer specialist Angie Lau revealed that many of the sanitizers didn't work for her, and the investigation raised a lot of serious questions.

Lau said that when consumers use antibacterial sanitizers, they expect them to work.

But in her investigation, she discovered the opposite -- the bacteria count was not much different even after using some sanitizers.

"If the purpose of buying antibacterial sanitizer is to get rid of bacteria, I would say you are wasting your money," said Dr. Val Flechtner.

She asked chemistry professor Dr. Mike Setter, who took on the task of testing the products, just how much ethyl alcohol were in each product.

Lau reported he found that the products do have what they claim.

"It tells me that something else in the formula affects the efficiency, it's not just the alcohol," Setter said.

One company that is not worried is GOJO, makers of Purell.

In Lau's test, Purell passed. A petri dish showed bacteria before using Purell, but afterward, it was significantly reduced.

The makers of Purell said the formula is what makes the difference.

"We have a pretty exhaustive testing system. As I mentioned before, we repeatedly and routinely test along all parts of the manufacturing process," said Kathleen Hooker.

Lau discovered that many of the generic products that tried to simulate Purell's name brand reverse engineered the formulation.

The FDA allows manufacturers to claim the product works if it has at least 60 percent ethyl alcohol. But Lau's tests suggested it may be the formulation and not just the active ingredient that matters.