Airplane food has long been the butt of jokes for being bland, unimaginative and generally unappetizing, but now there is evidence to suggest that the meals served by airlines are not just lackluster, but they might actually make passengers sick.

Inspections of airlines and outside caterers conducted by the Food and Drug Administration (FDA) have revealed facilities crawling with mice, roaches and ants, and food preparation areas swarming with flies.

According FDA health violation records obtained by ABC’s 20/20, over the past four years, there have been more than 1,500 violations in the airline food industry. The federal agency said that “significant” problems were found at a much higher rate than in other industry it inspects.

The FDA reported evidence of mice on Delta Airlines planes. In response, the carrier released a statement calling the findings an “isolated incident’. The statement goes on to say that the inspections, some of them dating back to 2009, were conducted in lavatory service trucks and aircraft potable water, and the problems uncovered by the agency have since been addressed.

Insects were also found inside the facilities of the industry giant LSG Sky Chefs which provides food for several airlines. According to the FDA records, inspectors have observed ants crawling over discarded food, flies both dead and alive, and roaches through the company’s food preparation facilities.

The company issued a statement saying that after being issued a warning letter by the FDA regarding food safety violations, LSG immediately addressed the problems to ensure complete compliance.

The catering service added that “food safety and quality are out number one priority”.

Inspections of airlines and outside caterers conducted by the FDA have revealed facilities crawling with mice, roaches and ants, and food preparation areas swarming with flies

Another company cited in the FDA records is airline food provider Gate Gourmet, whose facilities were said to be crawling with gnats “too numerous to count”, as well as roaches.

Besides critters in food facilities, FDA reports indicate that at several companies inspectors found other gross violations such as filthy cooking areas, old and moldy products and employees not washing their hands. For example, at the Gate Gourmet facilities, food was left outside refrigerators and utensils were stacked on dirty racks.

This is not the first time that airplane food safety concerns have been raised in the media.

In 2010, USA Today obtained FDA records painting a similarly unsettling picture: food being stored at improper temperatures, dirty equipment and signs of improper pest control in the shape of cockroaches, flies and mice.

Catering companies like LSG and others told ABC that they take food sanitation very seriously and make sure to address problems at once. They also said that they serve tens of millions of meals a year both at home and abroad without incident.

Passengers who spend several hundred dollars extra to fly first or business class in hopes of getting not only better plane accommodations, but also a superior meal, may find themselves disappointed.

According to Roy Costa, a food-industry consultant and former health inspector, a filet mignon presented on a china platter may suffer from the same problems as the grey mystery meat patty served on a plastic trey in coach.

“Fancy food isn’t safe food. The bacteria really don’t care,” he told 20/20.