The Food Standards Agency Scotland has produced some good advice with regards to pest control. This is one of their production that you will find very informative. FSA
You do not need to employ the services of a pest controller , however it is advisable.
The fines involved due to pest related offences are horrendous and could damage you reputation. Pest control is not all that expensive,in relation to the running costs of a business, why don’t you call for a quote today, after all prevention is better than cure.