State and local health departments usually conduct three different kinds of restaurant food safety inspections. The most common is known as a routine inspection and is conducted as often as every six months or as infrequently as every 18 months, depending on the type of food served and the restaurant's inspection history. The two other types of inspections are follow-up inspections to resolve outstanding violations and inspections triggered by a consumer complaint.
In most state and local health departments, routine inspections are scheduled based on a risk-based system that weighs the likelihood of a restaurant being the source of a foodborne illness. Higher-risk establishments are inspected more frequently than low-risk restaurants and are based on standardized risk factors established by the FDA.
The first risk factor has to do with the type of food served at the restaurant and how it's prepared. A corner deli that assembles cold-cut sandwiches, but doesn't actually cook anything, is considered a lower risk than a burger joint that handles and cooks raw ground beef. Likewise, a sushi bar is considered an even higher risk if it actually serves customers raw or undercooked seafood.
The second risk factor is a restaurant's inspection and compliance history. If a soup-and-salad joint has a recent record of violations, it's going to be inspected more frequently than the sandwich place around the corner that routinely aces its inspections. Restaurants with the very highest risk are those that have been the source of a known foodborne illness outbreak [source: Florida DPBR].
Restaurants are assigned an initial risk level when they're licensed, but that can change over the course of routine inspections. In Denver, the highest-risk restaurants will get inspected every six months, medium-risk places every 12 months and low-risk establishments every 18 months [source: Peterson]. In Florida, if a restaurant is the cause of an outbreak, it will be inspected every three months for the next year [source: Florida DPBR]. Inspection schedules are computer-generated for maximum efficiency and fairness.
In some cases, an inspector will cite a violation that requires a follow-up visit. Follow-up inspections are usually conducted within a week of the violation, especially if it poses a serious risk of foodborne illness.
Inspections also happen because of consumer complaints. All health departments have consumer hotlines and online forms for reporting unhygienic conditions, unsafe food handling or possible food poisoning from restaurants. Even though it's not always easy to identify the source of a foodborne illness, health departments follow up on every consumer complaint and look for unsafe cooking or cooling practices, or expired ingredients, that could have made customers sick.