The easiest way to test the effectiveness of a particular preservative would be to add this item to its intended food product and wait. The preservative would be considered effective if it kept the food from spoiling. Of course, most companies would now also conduct bacterial contamination tests. Government agencies, like the FDA, help regulate the definition of what constitutes spoiled and safe food products. In order for the test to be valid, it must be tightly controlled. Items containing the preservative would have to be closely monitored and regulated. Each sample would need to be subjected to the exact same conditions in order to be compared with a sample that does not contain the preservative. While testing consumer grade preservatives can be a lengthy process, the concept is as a simple as following the scientific method.