Both Delta and American Airlines have quietly resumed using a Los Angeles airport catering company where traces of listeria were found late last year.
The airlines stopped using Gate Gourmet at LAX when inspectors confirmed traces of the bacteria on their facility.
Other airlines including Qantas also stopped accepting in-flight meals from the company.
Traces of listeria in a floor drain were discovered during a random inspection although no confirmed cases of listeria were reported.
Gate Gourmet has since being working hard to regain the trust of its airline customers.
"Food safety is our highest priority. We reaffirm that our LAX facility is operating without restriction and continues to comply with all local and federal regulations as confirmed by independent food safety experts and agencies," a Gate Gourmet statement said.
Government health officials say about 1,600 cases of listeriosis are reported each year and more than 200 prove fatal.
