The listeria was discovered several weeks ago at a facility operated by Gate Gourmet near Los Angeles International Airport.
"During Food safety audits we were informed traces of listeria were found on surfaces that do not come into contact with food including drains and floor surfaces," an American Airlines spokesman told Business Insider.
Even though Gate Gourmet has come up with a corrective plan, American decided to suspend use of the facility on Wednesday.
"We were not satisfied with the cleanup efforts and decided to suspend food service out of the facility out of an abundance of caution," the American Airlines spokesman added.
According to the Centers for Disease Control and Prevention, symptoms of listeria include fever and diarrhea. Every year, about 1,600 people are affected by listeria in the US with pregnant women particularly vulnerable.
Thus far, there are no reports of any ill passengers as a result of the listeria and the facility remains in use by half a dozen other airlines.
In a statement to Business Insider, Gate Gourmet said:
"One of our customers notified us yesterday of their decision to temporarily suspend the catering services we provide at LAX. Food and passenger safety are our highest priorities. As part of routine inspections, we identified traces of listeria in non-food contact areas, primarily floor drains, at our LAX unit. Immediately and in accordance with our protocols, all floor drains and surrounding areas were immediately and aggressively treated. Independent food safety agencies have confirmed that our unit adheres to food safety regulations and we are not aware of any instance where passengers are put at risk. We reaffirm our commitment to food safety and the safety of the traveling public. Our unit is open for business and we continue to cater our other customers."
According to American, the airlines use a total of three catering companies and is working on securing alternative food service for its flights out of the LA. Some flights were able to secure snacks while others were made to do without food service at all.
A person at the airline told Business Insider that some of the company's flagship Los Angeles-New York flights were reduced to only drink service on Wednesday.
The airline expects the disruption to its LA catering operation to be corrected within a week to 10 days. Until then, passengers who are affected by the catering issues (i.e. business class passengers who don't get business class food) will receive vouchers from American Airlines.