The premises about an official establishment shall be free from conditions which may result in the contamination of food including, but not limited to, the following:
If the grounds of an official establishment are bordered by grounds not under the official establishment operator's control of the kind described in paragraphs (b) through (d) of this section, care must be exercised in the official establishment by inspection, extermination, or other means to effect exclusion of pests, dirt, and other filth that may be a source of food contamination.
50 C.F.R. § 260.98