Think of 4.13.8 asking the the question "is our pest control program up to date, and does it represent best practice?".
You already verify that all of the activities in your service contract (specification) are being performed through various internal audit practices. You are also ensuring through (minimum annual) trend analysis shows that everything remains in control.
The idea of a "pest control expert" would be someone who maintains an up to date knowledge of:
- regulatory changes (in countries of product sale)
- new pests of concern in the geography and industry
- emerging techniques, practices and technologies in pest control
- industry best practice, and emerging issues
Typically, this would be someone from your pest control contractor whose job it is to ensure those services in the contract represent current best practices. The terminology "typically quarterly" is not a concrete timeline - it should take into account the overall risk (location, geography, industry sector, past history....), the frequency of service, and site results.
Hopefully this helps a little.
John Kukoly
BRC