The owner of Gills Onions said he was surprised to receive a January warning letter from the Food and Drug Administration after several months of inspections, facility upgrades and ongoing communication with the agency in relation to listeria-related recalls in 2012.

Owner Steve Gill issued a statement Feb. 13 after the FDA posted a warning letter dated Jan. 23 that asked Gill to provide documentation of a plan to control listeria coming into his Oxnard, Calif., fresh-cut facility from raw product. The letter also recommended the company conduct weekly tests instead of monthly tests to check the facility for listeria.

“Over the past many months, we have taken extraordinary measures and executed sweeping changes, at significant cost, to ensure … the highest standards in food safety excellence,” Gill stated in the news release.

Gill also said his company simultaneously pursued the Global Food Safety Initiative-recommended Safe Quality Food single suppler standard. He listed 16 specific actions the company has taken to improve food safety, including “extensive changes” to its environmental monitoring and microbial testing program.

“Recently we were fully assessed by the licensed certification body NSF, were found to meet the demanding standards of SQF Code Ed. 7 and were recommended for SQF certification, for which we are awaiting final confirmation,” Gill’s statement said.

FDA spokeswoman Laurel Eu from the agency’s Los Angeles district said Feb. 13 that the Gills Onions case is still open and that she could not provide details on ongoing investigations.

The agency initiated the investigation after a random sample collected at retail July 5 returned positive results for listeria. Another random sample, collected at a wholesaler Aug. 27 also yielded positive listeria results.

The company issued a series of recalls — May 5, July 17, July 24, and Sept. 6 — for its fresh-cut onion and celery products. Those recalls spurred a cascade of related product recalls because the fresh-cut produce was used as ingredients in a number of other foods.

“We firmly believe that we have not only aggressively addressed regulatory recommendations, but have taken their comments significantly further,” Gill said in his statement.