What must be maintained around the facility to help prevent pests?

To prevent pests effectively around a facility, maintaining a vegetation-free zone is crucial. This practice involves ensuring that there are no plants or dense vegetation close to the building's foundation, which can harbor pests by providing them with shelter, food, and nesting sites. Shrubs, grass, and other forms of vegetation can attract insects and rodents, leading to infestations that can compromise food safety and hygiene standards.

By keeping the area around the facility clear of vegetation, it reduces the potential for these pests to gain access to the building. This proactive measure plays a vital role in pest management, ensuring that food products remain safe and the environment stays clean.

The other options may not be effective in controlling pests; for example, a tree line or a concrete barrier does not directly influence pest access in the same way that removing vegetation does, and a 10-foot buffer zone, while useful, does not specifically address vegetation that attracts pests.