There are many different types of pests that you could find in your business, and some of them are experts at hiding. While there are some signs that you can keep an eye out for, it is possible to make finding pests easier by using a thermal imaging camera.
If it is a larger pest, for example, rodents, these could be spotted from their body heat, even if they are hiding in a dark crevice somewhere in your business. It is also possible to find holes or cracks that they might have used to gain entry into your home.
If you were to have termites hiding inside the wood of your business, or other insects that act similarly, you might be able to find where there is a large concentration of them with an IR camera. You can also detect areas that are moist, which would provide something necessary for the pests to live inside your business.